Lower Limb Anatomy Class Notes

LOWER LIMB ANATOMY

CLASS NOTES SPRING 2009

KATHY J. SIESEL, D.P.M. COURSE COORDINATOR

This book of notes is to be used in conjunction with the drawings presented in class. An anatomy atlas will be very useful in this course as will attendance in the lecture and laboratory sessions, and completion of dissections in the laboratory.

TOPIC #1

INTRODUCTION AND REVIEW

I. LOWER EXTREMITY REGIONS AND SURFACES A. Regions 1. Gluteal Region - the buttock, extends from the posterior iliac crest to the gluteal fold 2. Hip Region / Coxal Region - anterolateral from inguinal ligament to the inferior extent of the hip joint 3. Thigh Region / Femoral Region - from the inferior aspect of the pelvis to the knee - has anterior, posterior and medial regions 4. Knee Region / Genus Region - between thigh and leg regions - has anterior and posterior regions 5. Leg Region / Crus Region - from the knee to the ankle - has anterior, posterior and lateral regions a. Calf Region / Sural Region - the rounded (shapely) part at the proximal posterior leg region 6. Ankle Region / Talus Region - between the leg and the foot - includes the medial and lateral malleoli 7. Foot Region / Pes Region a. Dorsal Region - the superior part or dorsum of the foot b. Plantar Region - the inferior part or planta of the foot - is divided into medial, lateral and central regions c. Calcaneal Region - the heel; medially, laterally and plantarly

B. Surfaces of the Lower Limb - described relative to anatomic position 1. Anterior Surface / Ventral Surface - the front side of a part, except the foot 2. Posterior Surface / Dorsal Surface - the back side of a part, except the foot 3. Medial Surface - the inner side of a part, toward body’s midline 4. Lateral Surface - the outer side of a part, opposite body’s midline 5. Flexor Surface - the surface over the flexor muscles - ex. the flexor surface of the leg is the posterior surface of the leg (opposite for the upper limb, due to limb rotations) 6. Extensor Surface - the surface over the extensor muscles - ex. the extensor surface of the thigh is the anterior surface of the thigh (opposite for the upper limb, due to limb rotations) 7. Adductor Surface - the surface over the adductor muscles - ex. the adductor surface of the thigh is the medial surface of the thigh 8. Abductor Surface - the surface generally over the abductor muscles - ex. the abductor surface of the thigh is the lateral surface of the thigh 9. Patellar Surface - the anterior surface of the knee region, over the patella 10. Popliteal Surface - the posterior surface of the knee region 11. Medial Malleolar Surface - the surface over the medial malleolus of the tibia at the ankle region 12. Lateral Malleolar Surface - the surface over the lateral malleolus of the fibula at the ankle region 13. Dorsal Surface of the Foot - the superior surface or dorsum of the foot 14. Plantar Surface of the Foot - the inferior surface, sole or planta of the foot

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II. ANATOMIC POSITION - The anatomic position is one in which the body is standing erect with the toes and palms facing anterior. - the position of reference for much terminology - In relaxed standing, the torso is slightly slouched; the toes are often directed slightly lateral and the palms are facing medially. III. TERMINOLOGY A. Descriptive - used to describe position 1. Superior, Cephalic, Cranial - toward the head - The knee is superior to the ankle. 2. Inferior, Caudal - away from the head - The foot is inferior to the ankle. 3. Anterior, Ventral - toward the front side - ventral is usually reserved for embryology - The patellar surface is anterior to the popliteal surface. 4. Posterior, Dorsal - toward the back side - dorsal is usually reserved for embryology, except when referring to the foot’s dorsum - The popliteal region is posterior to the patellar region. 5. Medial - closer to the midline (central line) of the body - The hallux (great toe) is medial to the 5th pedal digit. 6. Lateral - farther from the midline - The 4th pedal digit is lateral to the hallux. 7. Intermediate - between 2 structures - The ankle is intermediate to the leg and foot. 8. Ipsilateral - on the same side of the body - The right forearm is ipsilateral to the right lower limb. - most often used for neurology

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terminology, descriptive, con’t 9. Contralateral - on the opposite side of the body - The left arm is contralateral to the right thigh. - most often used for neurology 10. Proximal - closer to the origin/main structure - The thigh is proximal to the leg. 11. Distal - farther from the origin/main structure - The foot is distal to the knee. 12. Superficial - closer to the surface - Skin is superficial to bone. 13. Deep - farther from the surface, closer to the center - Muscles are deep to skin. B. Terminology of Movement 1. Flexion - decreasing the angle between body parts, generally - usually an anterior direction except at the knee and more distal joints where it is a posterior direction 2. Extension - increasing the angle between body parts, generally - usually a posterior direction except at the knee and more distal joints where it is an anterior direction a. Hyperextension - extension beyond the anatomic position - occurs normally at the neck, wrist, hip, ankle and MTP joints; The term is not usually used for hip, ankle or MTP joints 3. Abduction - moving a part away from the body’s midline 4. Adduction - moving a part toward the midline of the body 5. Rotation - moving around the long axis of a part - occurs primarily at the hip and shoulder joints

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terminology of movement, rotation, con’t a. Medial Rotation / Internal Rotation - anterior surface of the part moves toward the body's midline b. Lateral Rotation / External Rotation - anterior surface of the part moves away from the body's midline 6. Circumduction - movement of a part in a circular pattern - combines flexion and extension with abduction and adduction; movements must occur in alternating sequence 7. Eversion - moving the sole of the foot away from the body’s midline 8. Inversion - moving the sole of the foot toward the body’s midline 9. Dorsiflexion - extension of the ankle joint or joints distal to the ankle joint - bringing the dorsum of the foot closer to the anterior surface of the leg 10. Plantar Flexion - flexion of the ankle joint or joints distal to the ankle joint - moving the dorsum of the foot farther from the anterior surface of the leg 11. Supination - We will discuss supination as it relates to lower extremity anatomy, not the upper limb. - combination of plantar flexion, adduction and inversion of the foot - motion occurs at the functional subtalar joint and the midtarsal joint 12. Pronation - We will discuss pronation as it relates to lower extremity anatomy, not the upper limb. - combination of dorsiflexion, abduction and eversion of the foot - motion occurs at the functional subtalar joint and the midtarsal joint IV. BODY PLANES A. Frontal Planes / Coronal Planes - divide the body or body parts into anterior and posterior sections B. Transverse Planes - divide the body or body parts into superior and inferior sections C. Sagittal Planes - divide the body or body parts into right and left sections

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body planes, sagittal planes, con’t 1. Midsagittal Plane / Median Sagittal Plane - divides into equal right and left halves 2. Parasagittal Plane - any sagittal plane except the midsagittal plane D. Cardinal Body Planes - that plane which divides the body into equal parts 1. Cardinal Sagittal Plane - the midsagittal plane 2. Cardinal Frontal Plane / Cardinal Coronal Plane - divides the body into equal anterior and posterior halves 3. Cardinal Transverse Plane - divides the body into equal superior and inferior halves V. JOINTS / ARTICULATIONS - where two bones meet A. Arthrology - the study of joints B. Classification 1. Functional - based on the amount of movement available at a joint a. Synarthrosis - an immovable joint ex. sutures of the skull b. Amphiarthrosis - a slightly movable joint ex. symphysis pubis c. Diarthrosis - a freely movable joint - primarily these in lower limb ex. hip joint 2. Structural - based on the material that unites the bone ends a. Fibrous - united by fibrous tissue i. Sutures - of the skull - functional synarthroses ii. Gomphosis - between a tooth and the alveolus/socket - functional synarthroses 6

joints, structural classification, fibrous, con’t iii. Syndesmosis – 2 bones held together by a sheet of fibrous tissue ex. tibiofibular syndesmosis - functional amphiarthroses b. Cartilaginous - united by cartilage i. Primary Cartilaginous Joints – united by hyaline cartilage - temporary joints ex. Epiphyseal/growth plates - functional synarthroses ii. Secondary Cartilaginous Joints - united by fibrocartilage - permanent joints ex. intervertebral discs or symphysis pubis - functional amphiarthroses c. Synovial – primary type in lower limb - 5 components of synovial joints
articular capsule/fibrous joint capsule unites the bone ends
articular cartilage (usually hyaline cartilage) on the bone ends
synovial membrane lines the joint cavity except the articular cartilage and produces synovial fluid
synovial fluid produced by the synovial membrane and fills the joint cavity - lubricates and protects the articular cartilage
joint cavity, space between the bone ends and within the capsule - all synovial joints are functional diarthroses i. Plane/Planar/Gliding - bone ends are both flat surfaces - allow gliding movements only, no rotation ex. intertarsal joints ii. Hinge/Ginglymus - complex surface shapes that may involve more than 2 bones - allow movement in one plane; flexion and extension ex. ankle joint iii. Condyloid/Ellipsoid - 1 rounded, ball-like projection and 1 shallow saucer-like surface - allow movement in two planes; flexion and extension, abduction and adduction, and circumduction ex. metatarsophalangeal joints iv. Saddle/Sellar - 2 saddle shaped surfaces - allow movement in two planes; flexion and extension or abduction and adduction (not both at the same time) - have a small amount of rotation due to joint surface shapes ex. calcaneocuboid joint 7

joints, synovial, con’t v. Bicondylar - 2 large rounded projections contacting 2 saucer-like areas - allow movement primarily in one plane with a small amount of rotation ex. knee joint vi. Ball and Socket/Spheroid - 1 large rounded, ball-like projection and 1 cup-like depression - allow movements in three planes - have all movements - flexion, extension, abduction, adduction, circumduction, internal rotation and external rotation ex. hip joint VI. BONE A. Osteology - the study of bone 1. Ligament - dense connective tissue that connects bone to bone - often blend with articular capsules B. Types 1. Compact, cortical or dense - very solid - appears white on radiographs due to closely packed cells - provides strength to the bone 2. Cancellous, trabecular or spongy - appears as thin interlaced plates on radiographs due to loosely packed cells - has good blood supply for rapid healing a. Trabeculae - the "plates" or lattice pieces C. Classification 1. Placement a. Axial Bones - part of the axial skeleton - includes the skull, vertebrae, ribs, sternum and manubrium b. Appendicular Bones - part of the appendicular skeleton/limbs

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bone, appendicular, con’t i. Upper Limb - pectoral girdle (scapula and clavicle), humerus, radius, ulna, carpus, metacarpus, and manual phalanges ii. Lower Limb - pelvic girdle (os coxa), femur, patella, tibia, fibula, tarsus (greater and lesser), metatarsus, and pedal phalanges (in the toes) 2. Shape a. Long Bones - usually have greater length than width - found in the limbs - slight posterior/plantar concavity (curvature) in the lower limb for strength ex. femur i. Diaphysis/Shaft/Body - the central tubular part - primarily compact bone aa. Medullary Cavity - the hollow core in the diaphysis - contains bone marrow ii. Epiphyses - the ends of the bone - core of cancellous bone with a thin covering of compact bone, areas of articulation are covered with cartilage - epiphysis is singular iii. Metaphyses - flared part between the diaphysis and the epiphyses - core of cancellous bone with a thin covering of compact bone - metaphysis is singular b. Short Bones - roughly cube-shaped - found only in the carpus and tarsus - core of cancellous bone with a thin covering of compact bone ex. cuboid and cuneiforms c. Irregular Bones - complex shapes with varying amounts of cancellous and compact bone ex. vertebrae and facial bones d. Flat Bones - two parallel plates of compact bone with a minute amount of cancellous bone between the two plates ex. ribs and skull

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bone, shapes, con’t e. Sesamoid Bones - round or oval bones located within tendons and often joint capsules - functions: 1. protect the tendon from wear 2. create a mechanical advantage for the muscle by changing the angle of the pull and altering the muscle action ex. patella - largest sesamoid in the body and the sesamoids of the first metatarsal bone f. Accessory Bones / Accessory Ossicles - small bones with smooth regular edges - may be a non-fused portion of an existing bone or an extra bone - may be located within joint capsules ex. os intermetatarseum (between the metatarsal bases) and os supratalare - many in the foot D. Bone Markings The parentheses contain plural forms of these terms, which are not typical English plurals. 1. Foramen (foramina) - an opening (hole) for the passage of vessels and nerves ex. nutrient foramen, sacral foramina 2. Sulcus, Groove (sulci) - a ditch-like furrow for the passage of soft tissue structures ex. obturator groove, lateral malleolar sulcus 3. Fossa (fossae) - a depression in or on a bone ex. iliac fossa, lateral malleolar fossa 4. Notch - an indentation along the edge of a bone ex. greater sciatic notch 5. Condyle - a large rounded or depressed articular prominence ex. medial femoral condyle 6. Epicondyle - a small prominence superior to a condyle ex. medial epicondyle of the femur 7. Facet - a smooth flat surface for articulation ex. middle facet of the calcaneus

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bone, bone markings, con’t 8. Tubercle - a small rounded prominence for the attachment of soft tissue structures ex. adductor tubercle of the femur 9. Tuberosity - a large rounded prominence, often roughened for the attachment of soft tissue structures ex. tibial tuberosity 10. Trochanter - a large blunt process only on the femur ex. greater trochanter 11. Crest - a prominent border or ridge ex. median sacral crest 12. Line, Ridge - a ridge, much less prominent than a crest ex. soleal line of the tibia E. Ossification - all lower extremity bones begin as cartilage except the tufts of the distal phalanges - the tufts of the distal phalanges ossify through a process called intramembranous ossification - the ossification process from cartilage to bone is called endochondral bone formation or intracartilaginous ossification 1. Long Bones a. Primary Ossification Center - at midshaft of the bone - Primary ossification centers of all of the lower limb long bones are present at birth. - forms the major part of the diaphysis b. Secondary Ossification Centers - in the extremities (ends) - may be present at birth - one or more for each extremity - form the epiphyses c. Epiphyseal Plate/Physis - area of cartilage between the diaphysis and the epiphyses - allows for length-wise growth of bone - form the metaphyses and part of the diaphysis

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bone, ossification, con’t 2. Short Bones a. Center of Ossification - in the bone’s center - The center of ossification of some short bones is present at birth. - most only have one center of ossification - the calcaneus is an exception - secondary center of ossification is located posteriorly and is called the calcaneal apophysis b. Determination of Age - The appearance of the centers of ossification of the short bones of the foot can be used to determine a child's age radiographically. Using the bones of the hand is more accurate as there is less variability in the age of appearance of the centers of ossification of the manual short bones. VII. MUSCLES A. Myology - the study of muscles 1. Associated Structures a. Tendon - connective tissue continuation of the muscle - attaches muscle to bone i. Tendon Sheath - a double layer of connective tissue around a tendon with a small amount of fluid between the layers - allows tendon to glide freely when the muscle contracts or relaxes and prevents friction or damage to the tendon aa. Mesotendon - where the layers of tendon sheath meet each other - may remain as a single structure or partially or completely degenerate - Vincula - name given to areas of mesotendon that are present on the flexor tendons of the hand or foot - function: are areas for passage of vessels that nourish the tendon ii. Watershed Area - on tendons that do not have tendon sheaths - the area of a tendon where there is the greatest potential of injury due to a lack of blood supply - tendons without sheaths receive blood from the bone to which it attaches and from the muscle, majority from muscle - this creates an area where the two sources meet at the watershed b. Aponeurosis - flat connective tissue sheet - attaches muscle to muscle, muscle to bone or muscle to skin ex. plantar aponeurosis/plantar fascia

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muscles, associated structures, con’t c. Bursa - a fluid-filled sac that decreases friction between 2 structures; ligament and bone, ligament and ligament, muscle and bone, tendon and tendon, bone and skin i. Adventitious Bursa - located just beneath the skin and develops as a result of abnormal friction ex. over a bunion B. Types 1. Cardiac Muscle - heart muscle tissue 2. Non-striated Muscle / Smooth Muscle - muscle of viscera 3. Skeletal - voluntary muscle - also called striated muscle - poor terminology because cardiac muscle is also striated - preferable not to use this term a. Belly - contractile part of a skeletal muscle - actual muscle tissue b. Origin - the functional stable attachment that does not move - the proximal attachment from an anatomic view (and in this course) c. Insertion - the functional mobile attachment - the distal attachment from an anatomic view (and in this course) C. Naming 1. Direction of fibers - with respect to the body midline/part midline a. Rectus - parallel to midline ex. rectus femoris muscle and rectus abdominis muscles b. Transversus - perpendicular to midline ex. transversus abdominis muscle and transverse head of adductor hallucis muscle c. Oblique - angle less than perpendicular to the midline ex. oblique head of adductor hallucis muscle and internal oblique muscle (of abdomen)

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muscles, naming, con’t 2. Location - within the body ex. tibialis anterior muscle and plantar interossei muscles 3. Size a. Maximus - largest ex. gluteus maximus muscle b. Minimus - smallest ex. gluteus minimus muscle c. Magnus - large ex. adductor magnus muscle d. Longus - longest ex. adductor longus muscle e. Brevis - shortest ex. adductor brevis muscle 4. Number of Origins a. quadriceps femoris muscle has 4 origins b. biceps brachii muscle has 2 origins 5. Shape a. quadratus plantae muscle – quadrangular b. trapezius muscle - trapezoid 6. Origin and/or Insertion a. sternocleidomastoid muscle - mastoid process, sternum and clavicle b. iliacus muscle - iliac fossa 7. Action/Function a. flexor digitorum longus muscle - flexes the digits b. abductor hallucis muscle - abducts the hallux D. General Rule: Any muscle that crosses a joint has an action at that joint. (If you know the origin, course and insertion of a muscle, you can figure out the action or function.)

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VIII. VESSELS A. Types 1. Arteries - carry blood away from the heart a. Conducting / Elastic - large arteries - lumen diameter greater than wall thickness -ex. aorta, branches from aortic arch and the common iliac arteries - conduct blood (from the heart) to medium-sized arteries i. Vasa Vasorum - tiny vessels within the walls of conducting arteries to nourish these large vessels b. Distributing / Muscular - medium-sized arteries - lumen diameter about equal to wall thickness -ex. external and internal iliac, femoral, popliteal, anterior and posterior tibial, and peroneal arteries - distribute blood to different body parts; to arterioles in these parts c. Arterioles - small to very small arteries - large amount of smooth muscle in the walls that can change blood pressure by contracting or relaxing - supply individual structures within parts - direct blood to capillary beds; for exchange of nutrients and wastes d. End - an artery that is the only blood supply for an area - occlusion results in death of area -ex. ophthalmic artery, proper digital arteries 2. Veins - carry blood toward the heart - distal to proximal direction in limbs - valves - present within the veins - prevent the back flow of blood - aid the muscular pump in lower limbs to return blood to the heart; muscles contract and compress veins, blood flows proximal a. Veins / Venae Comitans - large veins - a vena comitans travels with its respective artery ex. femoral artery and femoral vein i. Vasa Vasorum - tiny vessels within the large vessel walls to provide nourishment ii. Superficial Veins - travel without arteries in the superficial fascia (layer beneath the skin) 15

vessels, veins, con’t b. Venae Comitantes / Venules - 2 or 3 small veins that accompany an artery - inferior to the knee in lower limb - referred to as venae comitantes of the _______ artery (ex. anterior tibial) - small veins that carry blood to large veins 3. Capillaries - microscopic vessels that allow exchange of nutrients and wastes for cells - direct blood to venules 4. Lymph Vessels - vessels that carry lymph fluid (like plasma), which extravasates (escapes) from capillaries - valves - present within lymph vessels - greater number than in veins; due to lower pressure in the lymphatic system to prevent back flow of the lymph fluid a. Lymph Capillaries - microscopic vessels that begin between cells; open-ended - transport lymph to afferent lymph vessels b. Afferent Lymph Vessels - small vessels that carry lymph fluid to lymph nodes c. Lymph Nodes - oval or kidney-shaped structures that filter lymph fluid before returning it to the general circulation d. Efferent Lymph Vessels - small vessels that carry lymph fluid away from from lymph nodes e. Lymph Trunks - large lymph vessels that collect lymph fluid from a region -ex. lumbar trunk collects from lower limb B. Anastomoses - communications between arteries and/or veins 1. Arterial - artery to artery communication - provides alternate source of blood supply to an area; more than one route to the same end - often called "collateral circulation", however it is actually not because collateral circulation has new vessels ex. genicular anastomosis

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vessels, anastomoses, con’t 2. Venous - vein to vein communication - provides alternate return route for blood - very common; possibly because of the lower pressure in the venous system as compared to the arterial system which makes it easier to occlude venous vessels C. Arteriovenous Shunts - communication between an arteriole and a venule - help regulate body temperature by directing blood away from the surface to deeper tissues or to the surface from deeper tissues - can be traumatically induced as in gunshot wounds and may need to be surgically repaired D. General Rule: Arteries tend to cross the flexor surface of muscles to prevent collapse, so they do not get stretched to closing or crushed. IX. NERVES A. Central Nervous System (CNS) - contained within the skull and spinal column 1. Brain - within the skull a. Afferent Fibers - carry impulses to nerve cell bodies in the brain b. Efferent Fibers - carry impulses to other (lower) nerve cell bodies in the CNS c. Nerve Cell Bodies 2. Spinal Cord - within the spinal column a. Afferent Fibers - carry impulses to other (higher) neurons in the CNS b. Efferent Fibers - carry impulses to other (lower) neurons in the CNS c. Nerve Cell Bodies - in the central grey matter - dorsal, ventral and lateral horns 3. Spinal Roots - within the spinal column - inferior to the spinal cord near the second lumbar vertebra, the spinal roots are long and are called Cauda Equina which means horse's tail

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nerves, spinal roots, con’t a. Dorsal Root/Dorsal Spinal Root i. Afferent Fibers - carry sensory impulses from peripheral areas to nerve cell bodies in the dorsal root ganglion ii. Dorsal Root Ganglion - collection of nerve cell bodies in the dorsal root b. Ventral Root/Ventral Spinal Root i. Efferent Fibers - carry motor impulses from nerve cell bodies in the central nervous system to peripheral areas (muscles) B. Peripheral Nervous System (PNS) - outside the skull and spinal column 1. Spinal Nerves - junction of dorsal and ventral roots, located at the intervertebral foramina a. Dorsal Primary Rami / Dorsal Primary Ramus - contain afferent and efferent fibers - caudal ones are small branches; lumbar, sacral and coccygeal dorsal rami supply motor and sensory innervation to the muscles of the spinal column b. Ventral Primary Rami / Ventral Primary Ramus - contain afferent and efferent fibers - large branches; lumbar, sacral and coccygeal ventral rami form plexuses and supply motor and sensory innervation to the lower limb C. Autonomic Nervous System (ANS) - innervates the viscera and smooth (non-striated) muscle of blood vessels and glands - an efferent or motor system 1. Sympathetic Nervous System - responses of stress or emergency situations - "fight, fright and flight" responses - increased heart rate and blood pressure - arise from thoracic and lumbar spinal cord and are distributed via the sympathetic chain; lower limb supply from T-10 through L-2 segments - follow blood vessels (external iliac and femoral aa.) or nerves (femoral n.) in the lower limb

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nerves, ANS, con’t 2. Parasympathetic Nervous System - conservation responses - decreased heart rate and respiration - arise from cranial and sacral segments of the central nervous system - follow other nerves or form nerves (pelvic splanchnic nerves) to supply the area - no supply to lower limb

Topic # 2

SUBCUTANEOUS LAYER, DEEP FASCIAE AND RETINACULA, NAIL ANATOMY, DERMATOMES

I. SUPERFICIAL FASCIA A. Def'n: the subcutaneous layer, immediately deep to the skin/cutaneous layer - composed of loose connective tissue and adipose (fat) tissue B. Contents - superficial veins, superficial lymph nodes and lymph vessels, and cutaneous nerves 1. Superficial Veins - carry blood from inferior to superior - can generally be seen through the skin - in athletes, many bulge beneath the skin - in general, pass superficial to the cutaneous nerves a. Common Dorsal Digital Veins (8) - label as 1 to 8 from medial to lateral or as medial and lateral of the digit - collect blood from the toe and drain into dorsal metatarsal veins ex. the 1st and 2nd common dorsal digital veins drain into the 1st dorsal metatarsal vein; and so on b. Proper Dorsal Digital Veins (2) i. Proper Dorsal Digital Vein of the Hallux - drains from the dorsomedial aspect of the hallux and 1st metatarsophalangeal joint - becomes the medial marginal vein ii. Proper Dorsal Digital Vein of the 5th Toe - drains from the dorsolateral aspect of the 5th toe and 5th metatarsophalangeal joint - becomes the lateral marginal vein

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superficial veins, con’t c. Marginal Veins - much variation with veins, can be difficult to distinguish these, may be absent i. Medial Marginal Vein - drains from the medial border of the forefoot and the proper dorsal digital vein of the hallux - drains into the great saphenous vein ii. Lateral Marginal Vein - drains from the lateral border of the forefoot and the proper dorsal digital vein of the 5th toe - drains into the small saphenous vein d. Dorsal Metatarsal Veins (4) - one for each intermetatarsal space - label as 1 through 4 from medial to lateral - each receives blood from 2 adjacent common dorsal digital veins and two perforating branches from deep layers of the foot - drain into the dorsal venous arch e. Dorsal Venous Arch - passes across the dorsum of the foot often at the level of the metatarsal bases - receives blood from dorsal metatarsal veins and sometimes the proper dorsal digital veins - drains into the great saphenous vein, medially and the small saphenous vein, laterally f. Small Saphenous Vein - begins as the union of the lateral end of the dorsal venous arch and the lateral marginal vein (or the proper dorsal digital vein of the fifth digit), then passes posterior to the lateral malleolus at the ankle region - travels superiorly near the midline of the leg, at the posterior aspect, to the popliteal area where it passes through the deep fascia to join the popliteal vein, which is part of the deep venous system g. Great Saphenous Vein - begins as the union of the medial part of the dorsal venous arch and the medial marginal vein (or the proper dorsal digital vein of the hallux), then passes anterior to the medial malleolus at the ankle region - travels superiorly at the medial aspect of the leg, passes posteromedially along the popliteal surface (usually about 1 hand breadth posterior to the medial edge of the patella) and continues in a superolateral direction to the groin where it passes through the saphenous opening/fossa ovalis in the deep fascia to join the femoral vein which is part of the deep venous system h. Superficial Plantar Venous Network - very thin intradermal and subdermal veins without valves - drain into medial and lateral marginal veins or into dorsal digital veins through perforating branches

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superficial fascia, contents, con’t 2. Lymph Nodes a. Inguinal Lymph Nodes - located in the inguinal region, groin (where the thigh meets the hip) - organized as 3 groups i. Superficial Inguinal Lymph Nodes - lie in the superficial fascia and are arranged as 2 groups - are usually palpable, but are firm and tender (painful to the patient) when inflamed - most efferent vessels pass to the external iliac lymph nodes in the pelvis; a few pass to the deep inguinal lymph nodes aa. Horizontal Group - lie along the inguinal ligament - drains the superficial areas of the inferior abdominal wall and a small area of the proximal anterior thigh bb. Vertical Group - lie along the termination of the great saphenous vein and the fossa ovalis - drains from the superficial areas of the thigh, leg and foot except the posterolateral aspect of the leg and the lateral aspect of the foot ii. Deep Inguinal Lymph Nodes (not pictured) - palpable only when inflamed - lie deep to the fascia lata, along the femoral vein near its termination - not in the subcutaneous layer - drain the deep tissues of the lower limb (tissues deep to the deep fascia) - efferent vessels pass to the external iliac lymph nodes in the pelvis b. Popliteal Lymph Nodes - are deep lymph nodes and palpable only when inflamed - lie along the small saphenous vein near its termination and deep to the popliteal fascia - drain the posterolateral aspect of the leg and the lateral aspect of the foot - efferent vessels pass to the deep inguinal lymph nodes c. Anterior Tibial Lymph Node (not pictured) - usually one or two deep lymph node(s) - lie near the proximal end of the anterior tibial artery near the interosseous membrane, deep to the muscles here - efferent vessels pass to the deep inguinal lymph nodes d. Subcutaneous Pedal Infections - an infection of the 5th toe will generally cause inflammation of the popliteal lymph nodes first, then inflammation of the deep inguinal lymph nodes - an infection of the hallux will generally cause inflammation of the vertical superficial inguinal lymph nodes first and this may pass to the deep inguinal lymph nodes, but definitely will pass to the external iliac lymph nodes

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superficial fascia, contents, con’t e. Deep Pedal Infections / Deep Infections of the Foot - from any area, will create inflammation of the deep inguinal lymph nodes - from dorsum of foot, will generally create inflammation of the anterior tibial lymph node, first - from planta of foot and calcaneal region, will generally create inflammation of the popliteal lymph nodes, first 3. Cutaneous Nerves - are nerves that exit the deep fascia and travel in the superficial fascia to supply the skin, sensory and autonomic sympathetic fibers - all are from ventral rami except where noted - know these a. anterior view i. Subcostal Nerve, T-12 - exits the deep fascia anterior to the iliac tubercle (lateral aspect of the hip) - supplies a small area at the anterolateral aspect of the thigh just inferior to the groin - cutaneous supply only in lower extremity ii. Femoral Branch of the Genitofemoral Nerve, L-1 & L-2 - passes deep to the inguinal ligament and exits the deep fascia near the fossa ovalis - supplies a small area at the anterior thigh just inferior to the groin and medial to subcostal nerve distribution iii. Ilioinguinal Nerve, L-1 - exits the deep fascia through the superficial inguinal ring (with the spermatic cord or round ligament of uterus) - supplies a small area at the medial aspect of the thigh just inferior to the groin iv. Lateral Femoral Cutaneous Nerve, L-2 & L-3 - also called the lateral cutaneous nerve of the thigh - exits the deep fascia near the anterior aspect of the iliac crest - supplies the anterolateral aspect of the thigh (from the subcostal nerve distribution to the knee) v. Intermediate Femoral Cutaneous Nerve, L-2 & L-3 - also called the intermediate cutaneous nerve of the thigh - sometimes replaced by the femoral branch of the genitofemoral nerve or branches of the lateral femoral cutaneous nerve - exits the deep fascia through the sartorius muscle lateral to the fossa ovalis - supplies the anterior aspect of the thigh (from the ilioinguinal and genitofemoral nerve distributions to the knee) vi. Medial Femoral Cutaneous Nerve, L-2 & L-3 - also called medial cutaneous nerve of the thigh - exits the deep fascia inferolateral to the fossa ovalis - supplies the anteromedial aspect of the thigh (from the ilioinguinal nerve distribution to the knee) 22

cutaneous nerves, anterior view, con’t vii. Obturator Nerve, L-2, L-3 & L-4 - exits the deep fascia at the medial aspect of the thigh near the junction of the proximal and middle thirds - supplies the central part of the medial aspect of the thigh (from the ilioinguinal nerve distribution to the inferior 1/3) viii. Lateral Cutaneous Nerve of the Calf, L-5, S-1 & S-2 - also called the lateral sural nerve - exits the deep fascia at the posterolateral edge of the knee region - supplies the lateral 1/2 of the leg from the knee to the inferior 1/3 leg ix. Saphenous Nerve, L-3 & L-4 - the only nerve of the leg region that can be traced to the lumbar plexus - exits the deep fascia at the inferomedial aspect of the thigh near the knee - supplies the entire medial ½ of the leg from the knee to the foot including the medial longitudinal arch; does not include the heel x. Superficial Fibular Nerve / Superficial Peroneal Nerve, L-4, L-5 & S-1 - exits the deep fascia at the anterolateral aspect of the leg near midlevel - supplies the anterolateral aspect of the inferior 1/3 of the leg, the anterolateral aspect of the ankle and the dorsum of the foot except the lateral ½ of the 5th digit and the 1st web space xi. Deep Fibular Nerve / Deep Peroneal Nerve, L-5, S-1 & S-2 - exits the deep fascia at the 1st webspace - supplies the 1st web space and the adjacent sides of the 1st and 2nd toes xii. Medial Calcaneal Nerve, S-1 & S-2 - exits the deep fascia at the posteromedial aspect of the ankle near the calcaneus; pierces the flexor retinaculum - supplies the medial ½ of the heel; medially, plantarly and posteriorly xiii. Sural Nerve, S-1 & S-2 - exits the deep fascia at the posterior aspect of the leg in the proximal 1/3 - supplies a small area of the posterior aspect of the leg from mid-calf, to the posterolateral aspect of the ankle, the lateral aspect of the foot, the lateral longitudinal arch and the lateral ½ of 5th toe b. posterior view i. Iliohypogastric Nerve, L-1 - exits the deep fascia near the lateral aspect of the iliac crest - supplies the superoposterolateral area of the gluteal skin, small area ii. Superior Cluneal Nerves, dorsal rami of L-1, L-2 & L-3 - also called the superior cutaneous nerves of the gluteal region - exit the deep fascia at the posterior aspect of the iliac crest - supply skin of superolateral aspect gluteal region

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cutaneous nerves, posterior view, con’t iii. Middle Cluneal Nerves, dorsal rami of S-1, S-2 & S-3 - also called the middle cutaneous nerves of the gluteal region - exit the deep fascia over the sacrum - supply skin of the medial aspect gluteal region iv. Posterior Femoral Cutaneous Nerve, S-1, S-2 & S-3 - main branch passes inferiorly along the anterior aspect of the fascia lata - small branches from the main branch exit the deep fascia all along the posterior aspect of the thigh, popliteal and calf regions - supplies the inferior gluteal region, the posterior aspect of the thigh, the popliteal fossa and the superior central aspect of the calf aa. inferior cluneal nerves, S-1, S-2 & S-3 - branches of the posterior femoral cutaneous nerve that supply the inferior area of the gluteal region - exit the deep fascia at the gluteal fold v. Perforating Cutaneous Nerve, S-2 & S-3 - branch from the sacral plexus - exits deep fascia at the inferomedial aspect of the gluteal region - supplies the inferomedial gluteal area skin vi. Obturator Nerve, L-2, L-3 & L-4 - described above vii. Medial Femoral Cutaneous Nerve, L-2 & L-3 - described above viii. Lateral Femoral Cutaneous Nerve, L-2 & L-3 - described above ix. Saphenous Nerve, L-3 & L-4 - described above x. Lateral Cutaneous Nerve of the Calf, L-5, S-1 & S-2 - described above xi. Sural Nerve, S-1 & S-2 - described above aa. lateral cacaneal nerves, S-1 & S-2 - branches of the sural nerve - arises in the superficial fascia between the calf and the ankle - supplies the lateral ½ of heel; laterally, plantarly and posteriorly xii. Superficial Fibular Nerve/Superficial Peroneal Nerve, L-4, L-5, S-1 - described above

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cutaneous nerves, posterior view, con’t xiii. Medial Plantar Nerve, L-4 & L-5 - small branches exit the deep fascia along the medial 2/3 of the plantar midfoot and forefoot - supplies the plantar medial aspect of the foot from just distal to the heel to the medial 3½ toes xiv. Lateral Plantar Nerve, S-1 & S-2 - small branches exit the deep fascia along the lateral 1/3 of the plantar midfoot and forefoot - supplies the plantar lateral aspect of the foot from just distal to the heel to the lateral 1½ toes xv. Medial Calcaneal Nerve, S-1 & S-2 - described above c. cutaneous nerves of the dorsum of the foot i. Superficial Fibular Nerve / Superficial Peroneal Nerve, L-4, L-5 &S-1 - courses inferomedially and divides just proximal to the ankle aa. Medial Dorsal Cutaneous Nerve - the medial division - passes anterior to the ankle near the center and is palpable here - supplies the medial part of the dorsal midfoot, then divides - aids in supply to 1st webspace - Proper Dorsal Digital Nerve 1 - the medial branch - supplies the dorsomedial aspect of the hallux - 1st Common Dorsal Digital Nerve - the lateral branch, passes in the 2nd intermetatarsal space dorsally and divides to supply the adjacent sides of the 2nd and 3rd toes as Proper Dorsal Digital Nerves 4 and 5, respectively bb. Intermediate Dorsal Cutaneous Nerve - the lateral division of the superficial fibular nerve - passes anterior to the ankle near the lateral malleolus - is easily palpated here - supplies the dorsolateral part of the midfoot and divides - 2nd Common Dorsal Digital Nerve - the medial branch, passes in the 3rd intermetatarsal space dorsally and divides to supply the adjacent sides of the 3rd and 4th toes as Proper Dorsal Digital Nerves 6 and 7, respectively - 3rd Common Dorsal Digital Nerve - the lateral branch, passes in the 4th intermetatarsal space dorsally and divides to supply the adjacent sides of the 4th and 5th toes as Proper Dorsal Digital Nerves 8 and 9, respectively 25

cutaneous nerves, dorsum of foot, con’t ii. Lateral Dorsal Cutaneous Nerve, S-1 & S-2 - is already in the superficial fascia at this level - the continuation of the sural nerve once it passes posterior to the lateral malleolus; the sural nerve is renamed at this point - supplies the lateral border of the foot aa. Proper Dorsal Digital Nerve 10 - the continuation of the lateral dorsal cutaneous nerve when it enters the fifth toe; the lateral dorsal cutaneous nerve is renamed at this point - supplies the dorsolateral aspect of the 5th toe iii. Deep Fibular Nerve / Deep Peroneal Nerve, L-5, S-1 & S-2 - exits the deep fascia in the 1st interspace, supplies it and divides aa. Proper Dorsal Digital Nerve 2 - supplies the dorsolateral aspect of the hallux and medial 1st interspace bb. Proper Dorsal Digital Nerve 3 - supplies the dorsomedial aspect of the 2nd toe and lateral 1st interspace iv. Saphenous Nerve, L-3 & L-4 - passes anterior to the ankle near the medial malleolus - supplies the medial border of the midfoot and part of the medial longitudinal arch d. cutaneous nerves of the plantar foot i. Medial Plantar Nerve, L-4 & L-5 - passes along the foot deep to the plantar fascia, sends cutaneous branches to the skin and divides near the forefoot aa. Proper Digital Plantar Nerve 1 - passes along the medial side of the forefoot, plantarly, exiting the deep fascia near the distal 1st metatarsal shaft - supplies the plantar medial aspect of the hallux and 1st metatarsophalangeal joint bb. 1st Common Digital Plantar Nerve - passes in the area of the 1st intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks - supplies this area and adjacent sides of the hallux and 2nd toe as the Proper Digital Plantar Nerves 2 and 3, respectively cc. 2nd Common Digital Plantar Nerve - passes in the area of the 2nd intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks - supplies this area and adjacent sides of the 2nd and 3rd toes as the Proper Digital Plantar Nerves 4 and 5, respectively

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cutaneous nerves, planta of foot, con’t dd. 3rd Common Digital Plantar Nerve - passes in the area of the 3rd intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks - supplies this area and adjacent sides of the 3rd and 4th toes as the Proper Digital Plantar Nerves 6 and 7, respectively ii. Lateral Plantar Nerve, S-1 & S-2 - passes along the plantar midfoot deep to the deep fascia, sends cutaneous branches to the skin and divides aa. Communicating Branch - a medial branch which joins the 3rd common digital plantar nerve bb. 4th Common Digital Plantar Nerve - passes in the area of the 4th intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks - supplies this area and adjacent sides of the 4th and 5th toes as the Proper Digital Plantar Nerves 8 and 9, respectively cc. Proper Digital Plantar Nerve 10 - passes along the lateral forefoot, plantarly, exiting the deep fascia near the distal 5th metatarsal shaft - supplies this area of the forefoot and the plantar lateral aspect of the 5th toe iii. Saphenous Nerve, L-3 & L-4 - supplies a small area of the medial longitudinal arch of the foot, plantarly iv. Sural Nerve, S-1 & S-2 - supplies a small area of the lateral longitudinal arch of the foot, plantarly v. Medial Calcaneal Nerve, S-1 & S-2 - small branches which supply the medial ½ of the calcaneal region vi. Lateral Calcaneal Nerves, S-1 & S-2 - small branches of the sural nerve which supply the lateral 1/3 to 1/2 of the calcaneal region

II. DEEP FASCIAE AND RETINACULA A. Def'n: deep fascia - dense connective tissue layer that surrounds muscles and attaches to many bony prominences and structures - deep fascia is continuous from one region to the next retinaculum - thickening of the deep fascia that holds soft tissue structures in place (ex. tendons)

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B. Deep Fasciae 1. Fascia Lata - deep fascia of the thigh a. Iliotibial (IT) Band / Iliotibial Tract - thickening of the fascia lata at lateral aspect of the thigh - provides partial origin or insertion site for several muscles - often visible at lateral edge of extended knee; especially in athletes b. Cribriform Fascia - very thin area of the fascia lata over the fossa ovalis / saphenous opening near the groin 2. Fascia Cruris - deep fascia of the leg region - aids in forming several retinacula near ankle 3. Popliteal Fascia - deep fascia of the popliteal region 4. Fascia Dorsalis Pedis - deep fascia of the superior aspect of the foot - aids in forming several retinacula near ankle 5. Plantar Fascia / Plantar Aponeurosis - deep fascia of the inferior aspect (sole) of the foot, a complex structure - several layers, some fibers attach to skin at all points along the plantar foot - aids in forming the retinacula near the ankle C. Retinacula 1. Flexor Retinaculum / Laciniate Ligament - thickening of fascia cruris, fascia dorsalis pedis and plantar fascia - attaches to the distal posterior aspect of the medial malleolus and to the medial aspect of the calcaneus - holds flexor tendons of the foot and creates a pulley to improve the muscle function - all tendons pass through the retinaculum and have separate tendon sheaths here 2. Superior Extensor Retinaculum / Transverse Crural Ligament - thickening of fascia cruris - attaches to the distal tibial shaft and to the distal fibular shaft, anteriorly - fibers are continuous with the flexor and superior fibular retinacula - holds extensor tendons of the foot and maintains their positions near the tibia - only one tendon sheath at this level; for the tibialis anterior muscle - all tendons pass deep to the retinaculum

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retinacula, con’t 3. Inferior Extensor Retinaculum / Cruciate Crural Ligament - Y-shaped band with the stem laterally - thickening of fasciae cruris and dorsalis pedis - attaches to the distal anterior medial malleolus and the medial plantar medial cuneiform, then to the lateral talus (neck) and the superior aspect of the calcaneus (in the sinus tarsi); described with 3 roots and 7 sinus tarsi attachments - continuous with the inferior fibular retinaculum - all tendons have tendon sheaths at this level and pass through this retinaculum - frondiform ligament - the stem of the inferior extensor retinaculum, attaches in the sinus tarsi 4. Fibular Retinaculum / Peroneal Retinaculum / External Annular Ligament - really 2 separate retinacula - thickening of fasciae cruris and dorsalis pedis a. Superior Fibular Retinaculum / Superior Peroneal Retinaculum - attaches to the posteroinferior lateral malleolus and to the lateral calcaneus (retrotrochlear eminence) - formed by fascia cruris - holds peroneal tendons and creates a pulley at the lateral malleolus - both are in single tendon sheath here and pass deep to retinaculum - fibers are continuous with superior extensor retinaculum b. Inferior Fibular Retinaculum / Inferior Peroneal Retinaculum - attaches to the sinus tarsi (anterolaterosuperior calcaneus) and to the fibular trochlea (posterolaterocentral calcaneus) then to posterolateroinferior calcaneus (near the lateral tubercle) - formed by fascia dorsalis pedis - holds peroneal tendons and creates a pulley for fibularis longus tendon at the distoplantar calcaneus - tendon sheath divides at this point and each tendon passes deep, separately - fibers continuous with lateral root of frondiform ligament

D. Intermuscular Septae (not pictured) - extensions of deep fascia that attach to bone and separate muscles or groups of muscles - muscles often take partial origin from or partially insert onto septae - in the leg, these septae aid in venous return (venous pump); there is little elasticity of the septae and muscular action creates compression on the deep veins which forces fluids superiorly (the valves normally prevent inferior flow), the empty deep veins refill from the superficial veins and so on

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III. NAIL ANATOMY A. Parts and Functions 1. Nail Plate - body of the nail (main part), normally .5 - .75 mm thick in an adult - is a hardening of the epidermis - cells have no nuclei, therefore are transparent, so can see the capillary bed - function: protect the distal end of the digit / toe 2. Matrix - "root" of the nail - specialized cells within the roof and floor of the proximal nail fold - attached to the base of the distal phalanx - extends approximately 5 mm proximal to visible nail edge - function: produce nail plate 3. Eponychium / Proximal Nail Fold - the skin fold at the proximal edge of the nail plate - overlies the matrix 4. Cuticle - small ridge of transparent skin dorsal to the proximal edge of the nail plate which is continuous with the eponychium - creates a seal around the nail - function: prevent infection by sealing the area adjacent to the nail plate 5. Nail Bed - skin directly beneath and attached to the nail plate, contains some nailforming cells; the cells that are attached to the nail plate migrate distally and are shed at the free edge of the nail - from matrix and lunula to the hyponychium - function: anchor the nail plate and allow its distal growth - sensory innervation to the nail bed is variable and may be entirely from the proper digital plantar nerves or from the plantar and dorsal proper digital nerves; therefore, you must take care when anesthetizing (blocking) digits for for nail procedures - it is safest to anesthetize both sets of nerves 6. Lunula - the small pale half-moon-shaped area near the eponychium; whitish because the cells retain nuclei and the capillaries beneath this portion of the nail plate are not visible - function: produce nail 7. Free Edge of the Nail Plate - distal edge of nail plate that overhangs the toe - function: protect the distal tuft of the toe from blunt trauma (being smashed) 8. Hyponychium - the thickened skin adjacent to the free edge of the nail plate - function: prevent infection by sealing this area adjacent to the nail plate 30

nail anatomy, con’t 9. Distal Nail Groove - the shallow transverse groove between the hyponychium and the skin of the distal tuft of the toe 10. Lateral Nail Folds /Ungualabia - the convex skin fold at the sides of the nail plate - after a successful permanent nail procedure the lateral nail folds will abut the remaining nail plate 11. Lateral Nail Grooves - the concave junction of the lateral nail fold with the nail bed - under the side edges of the nail plate B. Growth of Nails - nails grow primarily from the matrix and the proximal nail bed (level of the lunula) and are pushed distally - the cells of the nail bed migrate with the nail plate - nails grow faster in younger people and faster in the summer - finger nails grow faster than toe nails - finger nail takes approximately 6 months for replacement - toe nail takes approximately 9 months for replacement - sickness causes a disturbance in growth of the nail plate - nail growth requires much protein synthesis and illness retards this - have a resultant transverse ridge / Beau’s Line - little white spots - due to incomplete keratinization of the nail plate, cells still have nuclei or an air bubble formed in the nail plate due to a minor disturbance in growth - longitudinal ridges - often due to mechanical damage to the matrix cells

IV. DERMATOMES A. Def'n: the sensory innervation of an area of skin which is supplied by a single spinal nerve’s dorsal root B. Distribution in the lower limb - there is overlap among adjacent segments, so often it is necessary to destroy more than 1 spinal nerve dorsal root to have a noticeable area of deficit - all begin at the spinal level indicated and travel in a general spiral manner as they pass distal 1. L-1 / first lumbar - posterior at the level of the 1st lumbar vertebra - supplies an area superior to the hip, posteriorly and superior thigh at the groin near its termination

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dermatomes, con’t 2. L-2 / second lumbar - posterior at the level of the 2nd lumbar vertebra - courses just inferior to L-1 - supplies an area over the posterolateral iliac crest (hip bone prominence) and the anterosuperior aspect of the thigh to the mid-level at the medial aspect of the thigh 3. L-3 / third lumbar - posterior at the level of the 3rd lumbar vertebra, the mid-low back area - supplies an area over the posterior iliac crest, the superior part of the lateral aspect of the thigh, the central part of the anterior aspect of the thigh, the inferior part of the medial aspect of the thigh, the medial aspect of the knee region -not the patellar surface- and the superior ½ of the medial aspect of the leg 4. L-4 / fourth lumbar - posterior at the level of the 4th lumbar vertebra - supplies an area over the posterosuperior gluteal region, the anteroinferior thigh, the patellar surface, the central part of the anterior aspect of the leg, the medial malleolus and the medial aspect of the midfoot and forefoot, including the hallux 5. L-5 / fifth lumbar - posterior at the level of the 5th lumbar vertebra, the low back - supplies an area over the posterior iliac crest near the spine, the superolateral gluteal region, the inferior part of the lateral aspect of the thigh, the lateral aspect of the knee region, the anterolateral aspect of the leg, the anterior aspect of the ankle, the central part of the dorsum of the foot, toes 2 through 4, the central part of the plantar aspect of the forefoot and a small part of the calcaneal region (plantar and posterior, lateral to midline) 6. S-1 / first sacral - posterior at the level of the 1st sacral vertebra, the low back - supplies an area of the posterior mid-gluteal region, the posterolateral aspects of the thigh and leg, the lateral malleolus, and the lateral aspects of the calcaneal region, midfoot and forefoot, including the fifth toe 7. S-2 / second sacral - posterior at the level of the 2nd sacral vertebra - supplies an area of the posterior central gluteal region, the posteromedial aspects of the thigh (including the perigenital area), knee and leg regions, and the medial ½ of the calcaneal region 8. S-3, S-4, S-5 & Co-1 / third, fourth and fifth sacral and first coccygeal - all begin posteriorly at the respective spinal vertebral level - all form concentric arcs; with the third sacral being the largest over the posteromedial gluteal area, and the first coccygeal being the smallest around the perianal area

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V. MYOTOMES A. Def'n: the group of muscles that are supplied by a single spinal nerve’s ventral root B. Distribution - described in terms of movements at joints - have overlap of the segments - are sometimes reported with slightly different levels because it is difficult to trace nerves 1. Hip Joint a. Flexion, Adduction, Medial Rotation - L-1 through L-4 b. Extension, Abduction, Lateral Rotation - L-4 through S-1 2. Knee Joint a. Extension - L-2 through L-4 b. Flexion - L-5 & S-1 3. Ankle Joint a. Dorsiflexion - L-4 & L-5 b. Plantar flexion - S-1 & S-2 4. Subtalar Joint a. Inversion/Supination - L-4 & L-5 b. Eversion/Pronation - L-5 & S-1 5. Metatarsophalangeal Joints a. Dorsiflexion - L-5 & S-1 b. Plantar flexion - S-1 & S-2

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myotomes, con’t C. Deep Tendon Reflexes/Spinal Reflexes 1. Def'n: a. deep tendon reflex (DTR) - a muscle stretch reflex (These are commonly tested in a physician's office.) - mediated in the spinal cord b. spinal reflex - a withdrawal response - a protective reflex - mediated in the spinal cord 2. Deep Tendon Reflexes We will discuss the most commonly tested reflexes for the lower limb. There are others, but these test the majority of the spinal segments for the lower limb. a. Patellar Reflex - at the anterior knee/patellar tendon; with the knee flexed and relaxed, tap the tendon and normally will get a small extension response - tests spinal segments L-2, L-3 & L-4, the knee extensor myotome b. Achilles Reflex - at the posterior ankle/Achilles tendon; with the ankle slightly dorsiflexed, tap the tendon and normally will feel the contraction of the calf muscles - tests spinal segments S-1 & S-2; the ankle plantar flexor myotome 3. Spinal Reflexes a. Babinski Test - stroke the sole of the foot from central plantar heel in an arc to the base of the fifth metatarsal with a firm blunt object (ex. pen cap, finger nail tip) - normally will see plantar flexion of the toes; expected reaction - dorsiflexion of the hallux with abduction of the lesser digits (flaring of toes) is abnormal after 2 years of age

TOPIC #3 OSTEOLOGY - GLUTEAL AND PELVIC REGIONS I. Pelvis - composed of 4 bones: 2 pelvic (hip) bones, the os coxae 1 sacrum 1 coccyx - function: contain and protect pelvic organs aid in locomotion via force transfer

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osteology of pelvis, con’t - Pelvic Girdle = 2 pelvic bones - function: attach lower limb to the trunk A. Sacrum - forms a primary curvature of spinal column, same direction as fetal curvature - 5 vertebrae fused into one wedge-shaped bone - recognized by its distinctive shape 1. Base - superior end - articulates with L-5 vertebra 2. Apex - inferior end - articulates with the coccyx B. Coccyx (tail bone) - 4 vertebrae fused into 2 or 3 segments 1. Base - superior end - articulates with the apex of the sacrum 2. Apex - inferior end C. Features of Sacrum and Coccyx anterior surface of the sacrum - concave side to side and superior to inferior 1. Transverse Ridges (4) - formed by fusion of the vertebral bodies - last area in the body to complete ossification 2. Anterior Sacral Foramina (4 pair) - allow passage of the ventral rami S-1 through S-4 - holes at anterolateral sacral canal 3. Sacral Promontory - anterior superior edge of S-1 vertebra - projects in anteroinferior direction in body 4. Sacral Alae (ala means wing) - expansions from the base, laterally - the fused transverse processes of S-1 vertebrae 5. Superior Articular Processes - unfused superior articular processes of S-1 - visible from anterior side, are part of the posterior aspect - articular surface is posterior anterior surface of coccyx - no true features from anterior 35

pelvic osteology, sacrum, con’t posterior surface of sacrum 1. Superior Articular Processes - described above 2. Sacral Alae - described above 3. Sacral Canal - spinal canal of the sacrum for passage of cauda equina 4. Median Sacral Crest - midline projection from sacrum - the fused spinous processes of S-1 through S-4 5. Sacral Hiatus - the inferior opening of the sacral canal - formed by the lamina from S-5 that do not fuse - for passage of meninges and spinal nerves 6. Sacral Cornu - small projections at the lateral margins of the sacral hiatus - formed by ligamentous attachment 7. Posterior Sacral Foramina (4 pair) - for passage of dorsal rami S-1 through S-4 8. Intermediate Sacral Crest - projection at the medial edge of the dorsal sacral foramina, and lateral to the median sacral crest - formed by fusion of the superior and inferior articular processes 9. Sacral Groove - depressed area between median and intermediate sacral crests - formed by fusion of the vertebral laminae S-1 through S-4 10. Lateral Sacral Crest - projection lateral to the dorsal sacral foramina - formed by fusion of the transverse processes posterior surface of coccyx 1. Coccygeal Cornu - superior articular processes of Co-1 vertebra - articulate with sacral cornu via ligamentous attachment

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pelvic osteology, sacrum, con’t lateral view of sacrum and coccyx 1. Lateral Surfaces a. Auricular Surface - anterior part of the lateral surface, articulates with the pelvic bone - part of the sacroiliac joint, a synovial joint b. Sacral Tuberosity - posterior part of the lateral surface, for attachment of ligaments 2. Sacral Ala - described above 3. Sacral Promontory - described above 4. Superior Articular Process - described above 5. Posterior Sacral Foramina 1,4 - described above 6. Median Sacral Crest - described above 7. Sacral Groove - described above 8. Intermediate Sacral Crest - described above 9. Sacral Cornu - described above 10. Lateral Sacral Crest - described above 11. Coccygeal Cornu - described above D. Ossification of Sacrum 1. Primary Centers of Ossification - all present at birth - one in each vertebral body, one in each segment of the lateral masses, one in each of the lamina (around the sacral canal) 2. Secondary Centers of Ossification - appear between puberty and age 20 years - (in the upper and lower surfaces of the bodies, the spinous processes, the transverse processes, and the lateral surfaces) - all fused by age 25 years except transverse ridges which take until middle age

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pelvic osteology, con’t E. Pelvic Bone (2) - also called os coxa or innominate bone - articulates posteriorly with the lateral surface of the sacrum, anteriorly with the symphyseal surface of the other pelvic bone and laterally with the femoral head - composed of three bones fused into one - recognized by its distinctive shape 1. Ilium (not ileum) - the large superior portion of the pelvic bone a. iliac body - the central part (more inferior) b. iliac ala - the wing (large flattened part) 2. Ischium - the posteroinferior portion of the pelvic bone a. ischial body - the posterosuperior part; triangular in a cross-sectional view i. femoral surface - the external surface; faces laterally (not seen on picture) ii. pelvic surface - the internal surface; faces medially iii. dorsal surface - the posterior surface (not seen on picture) b. ischial ramus - the anteroinferior projection i. anterior surface - the external surface; faces laterally - rough from soft tissue attachment ii. posterior surface - the internal surface; faces medially - smooth area 3. Pubis - the anteroinferior portion of the pelvic bone a. pubic body - the large anteromedial part i. symphyseal surface - the flattened medial surface of the body - articulates with the other symphyseal surface at the pubic symphysis ii. femoral surface - the anterior/external surface (not seen on picture) iii. pelvic surface - the posterior/internal surface (not seen on picture) b. superior pubic ramus - the superior posterolateral projection i. obturator surface - the anterior surface at the medial end which spirals to an inferior position at the lateral end and is the continuation of the femoral surface of the body ii. pectineal surface - the superior surface - narrow medially, expands laterally 38

pelvic osteology, pelvic bone, superior pubic ramus, con’t iii. pelvic surface - the internal surface - wide medially, narrows laterally c. inferior pubic ramus - the inferoposterolateral projection - joins the ischial ramus - together the inferior pubic ramus and the ischial ramus may be referred to as the conjoined ramus or ischiopubic ramus - can not distinguish one bone from the other after fusion F. Features of the Pelvic Bone medial view 1. Iliac Crest - the superior border of the ilium or of the iliac ala - can be palpated along its entire length - most patients call this the hip bone 2. Anterior Superior Iliac Spine (ASIS) - the anterior rounded end of the iliac crest - can be palpated - often used as a reference point to measure limb length - for attachment of ligaments and muscle 3. Posterior Superior Iliac Spine (PSIS) - the posterior rounded end of the iliac crest - can be palpated, but may be difficult - lies beneath the skin dimple at the low back - for attachment of ligaments and muscle 4. Anterior Inferior Iliac Spine (AIIS) - the small projection on the anterior border of the ilium just inferior to the anterior superior iliac spine - can often be palpated just medial and inferior to the anterior superior iliac spine depending upon weight - for attachment of muscle and ligament 5. Posterior Inferior Iliac Spine (PIIS) - the small projection on the posterior border of the ilium just inferior to the posterior superior iliac spine 6. Iliac Fossa - the flattened internal or pelvic surface of the ala (wing) of the ilium - for attachment of a muscle

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pelvic osteology, pelvic bone features, con’t 7. Iliac Tuberosity - roughened area on the posteromedial surface of the ilium, posterior to the iliac fossa and anterior to the posterior superior iliac spine - for the attachment of ligaments 8. Auricular Surface - the synovial joint surface on the posteromedial surface of the ilium, posterior to the iliac fossa and inferior to the level of the posterior superior iliac spine - for articulation with the auricular surface of the sacrum at the sacroiliac joint 9. Ischial Spine - the small sharp projection on the posterior border of the ischium - inferior to the posterior inferior iliac spine - for attachment of ligament 10. Greater Sciatic Notch - the large concavity posteriorly - intermediate to the posterior inferior iliac spine and the ischial spine - closed by the sacrospinous ligament to form the greater sciatic foramen, then allows passage of neurovascular structures and the piriformis m. 11. Ischial Tuberosity - the large blunt projection on the posterior inferior aspect of the ischium - weight-bearing when seated; the area of problem when "saddle sore" - can be palpated through the soft tissue at the inferomedial gluteal region - for attachment of ligament and muscles 12. Lesser Sciatic Notch - the small concavity intermediate to the ischial spine and the ischial tuberosity - closed by the sacrotuberous ligament to form the lesser sciatic foramen, then allows passage of neurovascular structures and obturator internus m. 13. Obturator Foramen - the large hole in the pelvic bone formed by the ischial ramus, the ischial body, the pubic body and the pubic rami 14. Pubic Crest - the small roughened ridge at the anterior surface of the pubis - extends from the symphyseal surface to the pubic tubercle - can be palpated at the anteroinferior aspect of the abdomen - for attachment of ligament and muscle 15. Pubic Tubercle - the small prominence at the lateral edge of the pubic crest - can be palpated about 1" from the median plane - for attachment of ligaments 16. Arcuate Line - separates the iliac body and ala 40

pelvic osteology, pelvic bone features, con’t 17. Pecten Pubis / Pectineal Line - the border between the pectineal and pelvic surfaces of the pubis - continuous with the arcuate line of the ilium via the iliopectineal line 18. Iliopectineal Eminence / Iliopubic Eminence - a rise located at the junction of the iliac body and the superior pubic ramus - the iliopectineal line traverses its medial edge and connects the pectineal line with the arcuate line 19. Obturator Groove / Obturator Sulcus - central at the inferior part of the superior ramus of the pubis - at the superior edge of the obturator foramen - closed to the obturator canal by the obturator membrane, then allows passage of neurovascular structures 20. Symphyseal Surface - the flat surface on the medial surface of the pubic body - for articulation with the symphyseal surface of the opposite pelvic bone at the pubic symphysis, a secondary cartilaginous joint lateral view 1. Iliac Crest - described above 2. Anterior Superior Iliac Spine - described above 3. Posterior Superior Iliac Spine - described above 4. Anterior Inferior Iliac Spine - described above 5. Posterior Inferior Iliac Spine - described above 6. Greater Sciatic Notch - described above 7. Lesser Sciatic Notch - described above 8. Ischial Spine - described above 9. Ischial Tuberosity - described above 10. Iliac Tubercle - a prominence at the lateral lip of the iliac crest 1" to 2" posterior to the anterior superior iliac spine - can often be palpated at the superior lateral margin of the iliac crest - for attachment of ligaments and muscles

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pelvic osteology, pelvic bone features, con’t 11. Posterior Gluteal Line - shortest marking line on the external iliac ala - directed anteroinferiorly from near the posterior superior iliac spine to the level of the posterior inferior iliac spine - separates muscle attachments 12. Anterior Gluteal Line - longest and most distinct marking line on external iliac ala - directed posteroinferiorly from the iliac tubercle to the superior margin of the greater sciatic notch - sometimes continues anteriorly to the anterior superior iliac spine - separates muscle attachments 13. Inferior Gluteal Line - least defined marking line on external iliac ala - directed posteriorly from intermediate to the anterior superior iliac spine and the anterior inferior iliac spine to the greater sciatic notch - separates muscle attachments 14. Acetabulum - the large cup-like depression where the three bones meet - articulates with the femur at the hip joint, a synovial spheroid joint
superior 2/5 or 40% - formed by the body of the ilium
posterior inferior 2/5 or 40% - formed by the body of the ischium
anterior inferior 1/5 or 20% - formed by the superior pubic ramus a. Lunate Surface - the smooth, crescent-shaped, synovial articular surface of the acetabulum - for articulation with the femoral head b. Acetabular Fossa - the roughened central depression within the acetabulum - formed mostly by the ischial body - for passage of ligament and neurovascular structures c. Acetabular Notch - the depressed area between the ends of the lunate surface - formed mostly by the ischial body - closed to the acetabular foramen by the transverse acetabular ligament - for the passage of neurovascular structures d. Acetabular Rim - the outer, raised edge of the acetabulum - for attachment of ligaments and muscle 15. Obturator Foramen - described above 42

pelvic osteology, pelvic bone features, con’t 16. Obturator Crest - the sharp border between the pectineal and obturator surfaces of the pubis - at the anterior edge of the obturator groove G. Ossification of the Pelvic Bone - from 3 primary centers and 4 secondary centers 1. Primary Centers - one in each component bone a. ilium - appears near 9th fetal week - in the iliac ala b. ischium - appears early 4th fetal month - in the ischial body c. pubis - appears late 4th fetal month - in the superior pubic ramus 2. Secondary Centers - appear near puberty and fuse from ages 15 to 25 years a. iliac crest b. acetabulum c. pubic body d. ischial tuberosity H. Anatomic Position - in a living being, the pelvis is situated so that the anterior superior iliac spines and the pubic tubercles lie in the same coronal / frontal plane - pelvis appears to be tilted forward J. Pelvis 1. Brim of the Pelvis / Pelvic Inlet - the entrance to the true pelvis - structures that divide the pelvis into superior and inferior portions a. Linea Terminalis - continuous line of the lateral and anterior walls of the pelvis, internally - formed by four separate structures that align end to end i. Arcuate Line ii. Iliopectineal Line iii. Pectineal Line / Pecten Pubis iv. Pubic Crest

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pelvic osteology, pelvis, con’t b. imaginary line - across the sacral promontory and sacral alae (from one arcuate line to the other arcuate line) c. imaginary line - across the symphysis pubis - from one pubic crest to the other pubic crest 2. Greater Pelvis / False Pelvis - the pelvic area superior to the pelvic brim - located superior and anterior to the lesser pelvis - formed primarily by the iliac alae 3. Lesser Pelvis / True Pelvis - the pelvic area inferior to the pelvic brim - located posterior and inferior to the greater pelvis - formed by the pubic bones, ischial bones, iliac bodies, sacrum and coccyx 4. Pelvic Outlet - the inferior opening (exit) of the true pelvis - border between pelvis and perineum - generally larger in females for childbirth

II. FEMUR - the bone of the thigh - recognized by the angled head and the trochanters - largest bone in the body A. Features anterior view 1. Proximal Extremity - the superior end a. Head / Proximal Epiphysis - the smooth ball-like knob - articulates with the os coxa at the lunate surface of the acetabulum i. Fovea Capitis Femoris - the depression at the medial edge - for attachment of ligament and passage of a vessel b. Neck - the cylindrical part connecting the head with the body (shaft)

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osteology, femoral features, anterior view, proximal extremity, con’t c. Greater Trochanter / Trochanter Major - the large lateral bony projection at the junction of the neck and shaft - can be palpated at the lateral aspect of the hip - for attachment of ligament and muscle d. Lesser Trochanter / Trochanter Minor - small posteromedial projection at the junction of the neck and shaft - for attachment of muscle e. Intertrochanteric Line - ridge from the greater trochanter to just inferior to the lesser trochanter - for attachment of ligament and muscle 2. Shaft / Diaphysis - smooth, cylindrical area 3. Distal Extremity / Distal Epiphysis - inferior end of the femur - primarily smooth for articulation with the tibia at the knee joint a. Medial Condyle - the medial part of the epiphysis - can be easily palpated at the medial aspect of the knee joint - a synovial bicondylar joint i. Medial Epicondyle - the prominence on the medial aspect of the medial condyle - can be palpated at the proximomedial aspect of the knee - for attachment of ligament ii. Adductor Tubercle - the small sharp prominence at the superior edge of the medial epicondyle - can determine the area but is too surrounded by muscle to palpate it - for attachment of muscle b. Lateral Condyle - the lateral part of the epiphysis - easily palpated at the lateral aspect of the knee joint i. Lateral Epicondyle - the prominence at the lateral aspect of the lateral condyle - easily palpated at the proximolateral aspect of the knee - for attachment of ligament c. Patellar Surface - smooth anterior surface of the condyles for articulation with the patella - can palpate the margins with the knee flexed

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osteology, femoral features, con’t posterior view of femur 1. Proximal Extremity a. Head - described above i. Fovea Capitis Femoris - described above b. Neck - described above c. Greater Trochanter - described above i. Trochanteric Fossa - on the medial surface of the greater trochanter where it meets the neck of the femur - the more posterior and more distinct depression - for attachment of muscle ii. Unnamed Fossa - on the medial surface of the greater trochanter just anterior to the trochanteric fossa; sometimes very ill-defined - for attachment of muscle d. Lesser Trochanter - described above e. Intertrochanteric Crest - ridge from the greater trochanter to the lesser trochanter (posteriorly) i. Quadrate Tubercle - small square-shaped projection about midway along the intertrochanteric crest - for attachment of muscle 2. Shaft a. Linea Aspera - ridge consisting of three lines that passes lengthwise along the entire shaft on its posterior surface - for attachment of muscle i. Medial Lip - medial edge of the linea aspera - for muscular attachment aa. Spiral Line - superior continuation of the medial lip of the linea aspera - continuous with the intertrochanteric line anteriorly

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femoral features, posterior view, linea aspera, con’t bb. Medial Supracondylar Line - inferior continuation of the medial lip of the linea aspera - ends at the adductor tubercle ii. Intermediate Lip - central line of the linea aspera - only well-defined superiorly - for muscular attachment aa. Pectineal Line - superior continuation of the intermediate lip of the linea aspera - ends at the lesser trochanter iii. Lateral Lip - lateral edge of the linea aspera - for muscular attachment aa. Gluteal Tuberosity - superior continuation of the lateral lip; also has medial and lateral divisions - if enlarged, is called the Gluteal Trochanter / Third Trochanter bb. Lateral Supracondylar Line - inferior continuation of the lateral lip of the linea aspera - ends at the lateral epicondyle b. Popliteal Surface - the posterior inferior surface of the shaft of the femur c. Nutrient Foramen - hole directed superiorly, because it angles away from the more rapidly growing end of the bone - usually near the midpoint of the femur and between the medial and lateral lips of the linea aspera - may be two: in which case one is more proximal and one more distal - allows passage of vessels to nourish the shaft of the bone 3. Distal Extremity a. Medial Condyle - described above i. Medial Epicondyle - described above ii. Adductor Tubercle - described above b. Lateral Condyle - described above i. Lateral Epicondyle - described above

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femoral features, posterior view, distal extremity, con’t c. Intercondylar Notch / Intercondylar Fossa - the large depression between the medial and lateral condyles - provides attachment for ligaments d. Intercondylar Line - superior edge of the intercondylar fossa - for ligamentous attachment B. Ossification of the femur - 5 regular centers of ossification - the secondary centers fuse in reverse order of appearance between the 16th and 20th years 1. Primary Center - in the shaft of femur, near midshaft - appears during the 7th fetal week 2. Secondary Centers a. the femoral condyles - appears near birth, may be one or two b. the head of the femur - appears by 1st year c. the greater trochanter - appears between the 4th and 5th years d. the lesser trochanter - appears between the 12th and 14th years C. Anatomic Position - in living beings, the head and neck are angled in an anteromedial direction and the distal extremity is positioned medially (with the inferior surfaces of the condyles roughly parallel to the floor) - femoral shafts angle 10o to 15o in the frontal plane - can be measured by angles and compared to normal 1. Angle of Inclination - the angle formed by the long axis of the head and neck with the long axis of the shaft; the angle varies with age - frontal plane view - greater at birth (about 150o) and decreases until adulthood (about 125o) 2. Angle of Declination / Angle of Femoral Torsion - the angle formed by the long axis of the head and neck with the line of the bicondylar plane (usually the coronal plane of the condyles) - viewed on end, a transverse plane view - measures the amount of longitudinal twisting in the bone - varies with age - greater at birth (about 40o) and decreases until adulthood (about 10o) - twisting occurs in the extremities with growth 48

ARTHROLOGY & SYNDESMOLOGY OF THE PELVIS I. SYNDESMOLOGY A. Anterior View 1. Ventral Sacroiliac Ligament - anterior thickening of the sacroiliac joint capsule (joint between the auricular surfaces of the sacrum and the ilium) - stabilizes sacroiliac joint 2. Sacrotuberous Ligament - from the posterior superior iliac spine, posterior inferior iliac spine, the dorsolateral aspect of the sacrum and the dorsolateral aspect of the coccyx to the ischial tuberosity - stabilized the sacroiliac joint - closes the lesser sciatic notch and forms the lesser sciatic foramen - for passage of a muscle and neurovascular structures 3. Sacrospinous Ligament - from the dorsolateral margin of the inferior one-half of the sacrum and the dorsolateral margin of the coccyx to the ischial spine - stabilized the sacroiliac joint - closes the greater sciatic notch and forms the greater sciatic foramen - for passage of a muscle and neurovascular structures 4. Inguinal Ligament / Poupart's Ligament - from the anterior superior iliac spine to the pubic tubercle - the division between the hip and thigh regions, anteriorly 5. Lacunar Ligament / Gimbernat's Ligament - the most medial portion of the inguinal ligament where the fibers change direction and pass inferiorly 6. Pectineal Ligament / Cooper's Ligament - the extension of the lacunar ligament along the pubic pectineal line 7. Iliolumbar Ligament - stabilizes the sacroiliac joint a. Upper Band - from the anterior aspect of the 5th lumbar vertebra to the posterior part of the internal lip of the iliac crest b. Lower Band - from the anterior aspect of the 5th lumbar vertebra to the anterolateral aspect of the sacrum, superiorly

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pelvic region, syndesmology, con’t B. Dorsal View 1. Dorsal Sacroiliac Ligament - stabilize sacroiliac joint a. Long Dorsal Sacroiliac Ligament - from lateral crests of 3rd and 4th sacral vertebrae to the posterior superior iliac spine b. Short Dorsal Sacroiliac Ligament - from the intermediate and lateral crests of 1st and 2nd sacral vertebrae to the posterior superior iliac spine and the internal lip of the iliac crest posteriorly 2. Sacrospinous Ligament - described above 3. Sacrotuberous Ligament - described above C. Cross Section and Anterior View Pubic Symphysis 1. Ventral Sacroiliac Ligament - described above 2. Dorsal Sacroiliac Ligament - described above 3. Interosseous Sacroiliac Ligament - from the sacral tuberosity to the iliac tuberosity 4. Obturator Membrane - a sheet of deep fascia that covers most of the obturator foramen - for muscular attachment - closes the obturator groove to form the obturator canal - allows passage of the obturator nerve and obturator artery 5. Superior Pubic Ligament - from one pubic tubercle to the other - stabilizes pubic symphysis 6. Arcuate Pubic Ligament - connects the inferior borders of the pubic symphysis - stabilizes pubic symphysis

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II. ARTHROLOGY OF THE PELVIS A. Sacroiliac Joint - the articulation between the auricular surface of the ilium and the auricular surface of the sacrum - vertebral levels S-1 through S-3 - articular surfaces are covered by fibrocartilage (instead of hyaline cartilage) and adhesions form across the joints with age - capsule attaches at margins of each surface - structural synovial planar joint located between the lateral masses of the sacrum and the posterior portion of iliac alae - functional diarthrosis 1. Intrinsic Ligament a. Ventral Sacroiliac Ligament - a thickening of the joint capsule anteriorly - reinforces the sacroiliac joint anteriorly - thicker at the pelvic brim, arcuate line 2. Extrinsic Ligaments a. Interosseous Sacroiliac Ligament - very strong, thick ligament - stabilizes the sacroiliac joint - sometimes considered a syndesmosis b. Dorsal Sacroiliac Ligament - separated from the joint capsule by the interosseous sacroiliac ligament - reinforces the sacroiliac joint posteriorly 3. Accessory Ligaments a. Sacrospinous Ligament - prevents superior rotation of the pelvic bone on the sacrum during weight-bearing to aid in stabilizing the sacroiliac joint b. Sacrotuberous Ligament - prevents superior rotation of the pelvic bone on the sacrum during weight-bearing to aid in stabilizing the sacroiliac joint B. SYMPHYSIS PUBIS / PUBIC SYMPHYSIS - articulation located between the symphyseal surfaces of the pubic bodies - each joint surface is covered with hyaline cartilage that blends with a central pad of fibrocartilage, the interpubic disc - fibers strengthen the joint anteriorly - provides partial attachment for some thigh muscles - structural fibrous syndesmosis joint - functional amphiarthrosis

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pelvic region, arthrology, pubic symphysis, con’t 1. Ligaments a. Superior Pubic Ligament - provides stability at the superior end of the joint - from pubic tubercle to pubic tubercle b. Arcuate Pubic Ligament - provides stability at the inferior end of the joint - blends with the interpubic disc inferiorly - from inferior pubic ramus to inferior pubic ramus

PELVIC REGION The nerves of the lumbosacral plexus pass through or arise within the pelvic cavity. Many of these supply the lower limb. The arteries that supply the lower limb arise within the pelvic cavity. The muscles of the pelvic region that act upon the lower extremity are hip joint and thigh flexors.

I. MUSCLES OF THE PELVIS A. Iliacus Muscle O: superior iliac fossa (superior 2/3 and inner lip of the iliac crest) I: lesser trochanter of the femur - travels inferiorly and passes anteriorly over the hip joint and through the muscular lacuna to its insertion A: flexes the thigh NS: femoral nerve; from dorsal divisions of ventral rami L-2, L-3 & L-4 AS: muscular branches of common, internal and external iliac arteries B. Psoas Major Muscle O: T-12 through L-5 vertebrae (bodies, intervertebral discs and transverse processes) I: lesser trochanter of the femur - travels inferolaterally, joins the tendon of iliacus muscle and passes anterior to the hip joint and through the muscular lacuna to its insertion A: flexes the thigh NS: dorsal divisions of ventral rami L-2, L-3 & L-4, as branches exit spinal canal AS: muscular branches of common, internal and external iliac arteries - These two muscles are often considered one, and are called the iliopsoas muscle. They function to flex the thigh. 52

II. NERVE PLEXUSES - may be described as a single plexus, the “lumbosacral plexus"; as two plexuses, the "lumbar plexus” and the "sacrococcygeal plexus"; or as three plexuses, the "lumbar plexus", the "sacral plexus" and the "coccygeal plexus" - will describe as separate plexuses here and draw as two plexuses - all nerve branches in these plexuses are ventral rami

A. Lumbar Plexus - consists of the ventral rami of L-1 through L-3 with contributions from the ventral rami of T-12 and L-4 - most ventral rami have dorsal and ventral divisions - lies within the psoas major muscle just anterior to the transverse processes of of the vertebral bodies - shaded areas represent dorsal divisions of ventral rami on the picture 1. Subcostal Nerve - a sensorimotor nerve; cutaneous supply only in the lower limb - branch of T-12 that supplies the superior anterolateral aspect of the thigh - not usually considered part of the lumbar plexus 2. Iliohypogastric Nerve - a sensorimotor nerve; cutaneous supply only in the lower limb - from the ventral division of L-1 (may have a contribution from T-12) - pierces the psoas major muscle near the kidney and passes within the abdominal wall, inferior to the subcostal nerve, to reach the posterolateral gluteal skin (near the iliac crest, posteriorly) 3. Ilioinguinal Nerve - a sensorimotor nerve; cutaneous supply only in the lower limb - from the ventral division of L-1 (may have a contribution from T-12) - follows a course similar to the iliohypogastric nerve, but continues anteriorly (along the inguinal ligament and through the inguinal canal) to reach the skin of the superior medial thigh 4. Genitofemoral Nerve - a sensorimotor nerve; cutaneous supply only in the lower limb - from the ventral divisions of L-1 & L-2 - pierces the psoas major muscle anteriorly and enters the thigh dorsal to the inguinal ligament, near its center a. Genital Branch - passes medially, along the inguinal ligament to supply part of the external genitalia b. Femoral Branch - passes deep to the inguinal ligament with the femoral a. through the vascular lacuna to supply the skin of the anterior superior thigh - may aid or replace the intermediate femoral cutaneous nerve

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pelvic region, lumbar plexus, con't 5. Lateral Femoral Cutaneous Nerve - a sensory nerve; cutaneous supply only in the lower limb - from the dorsal divisions of L-2 & L-3 - pierces the psoas major muscle laterally and courses along the iliac fossa anterior to the iliacus muscle to enter the thigh anterolaterally, near the attachment of the inguinal ligament on the anterior superior iliac spine, and then supplies the anterolateral aspect of the thigh - the n. usually passes deep to the inguinal ligament, but may pass through it 6. nerves to psoas major muscle - from the dorsal divisions of L-2 through L-4 - these branches usually pass directly into the psoas major muscle belly, without uniting, to supply motor innervation to the muscle - these branches do not exit the pelvis - are not branches of the femoral nerve 7. nerve to iliacus muscle - a small branch from the femoral nerve, dorsal divisions of L-2 through L-4 - passes directly to the iliacus muscle without exiting the pelvis to provide it with motor innervation 8. Femoral Nerve - a sensorimotor nerve; from the dorsal divisions of L-2 through L-4 - passes inferiorly intermediate to the psoas major and iliacus muscles, enters the thigh by passing through the muscular lacuna deep to the inguinal ligament near its midpoint to provide muscular branches to the thigh, articular branches to the hip and knee joints and gives rise to the following cutaneous nerve branches: a. Intermediate Femoral Cutaneous Nerve(s) - dorsal divisions L-2 and L-3 - supplies a long, thin area of the anterior aspect of the thigh b. Medial Femoral Cutaneous Nerve(s) - dorsal divisions L-2 and L-3 - supplies a long, thin area of the anteromedial aspect of the thigh c. Saphenous Nerve - dorsal divisions L-3 and L-4 - supplies the medial 1/2 of the leg 9. Obturator Nerve - a sensorimotor nerve; from the ventral divisions of L-2 through L-4 - pierces the psoas major muscle medially near the linea terminalis, passes anteroinferiorly into the lesser pelvis and passes through the obturator canal to provide muscular branches to the thigh, articular branches to the hip and knee joints, and the cutaneous branch to the small area of the medial aspect of the thigh

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pelvic region, lumbar plexus, con't 10. Accessory Obturator Nerve - a sensorimotor nerve; from the ventral divisions of L-3 & L-4 - present in 8% of population - its course parallels the obturator nerve and, when present it provides muscular supply to pectineus muscle, an articular branch to the hip joint and joins the obturator nerve's cutaneous supply to the thigh 11. Lumbosacral Trunk - part of the ventral ramus of L-4 and the entire ventral ramus of L-5 unite to form a large nerve which crosses the sacroiliac joint anteriorly at the pelvic brim and joins the sacral plexus B. Sacral Plexus - formed by the ventral rami of L-5 through S-3 with contributions from ventral rami of L-4 and S-4 - roughly triangular in shape and passes inferiorly toward the greater sciatic foramen - shaded areas represent dorsal divisions on the picture 1. Superior Gluteal Nerve - a motor nerve; from the dorsal divisions of L-4, L-5 and S-1 - exits the pelvis via the greater sciatic foramen and passes posterolaterally through the gluteal region to supply the gluteus minimus, gluteus medius and tensor fascia lata muscles 2. Inferior Gluteal Nerve - a motor nerve; from the dorsal divisions of L-5, S-1 and S-2 - exits the pelvis via the greater sciatic foramen inferior to the superior gluteal nerve and passes posterolaterally through the gluteal region to supply the gluteus maximus muscle 3. nerve to piriformis muscle - from dorsal division of S-2, (may have contribution from dorsal division of S-1) - passes directly into the piriformis muscle - does not exit the pelvis before entering m. 4. Sciatic Nerve - the major formation of the sacral plexus - a sensorimotor nerve; from the dorsal divisions of L-4 through S-2 and the ventral divisions of L-4 through S-3 - exits the pelvis via the greater sciatic foramen and usually continues as a single nerve to the lower thigh; however it may divide into its two component parts at any level a. Common Fibular Nerve / Common Peroneal Nerve - a sensorimotor nerve; from the dorsal divisions of L-4, L-5, S-1 and S-2 - the lateral portion of the sciatic nerve - provides muscular innervation in the thigh and leg, articular innervation to the knee and proximal tibiofibular joints, and the following cutaneous nerve branches:

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pelvic region, sacral plexus, common fibular nerve, con’t i. Superficial Fibular Nerve / Superficial Peroneal Nerve - a sensorimotor nerve; from the dorsal divisions of L-4, L-5 & S-1 - supplies part of the anterolateral aspect of the leg and ankle, and most of the dorsum of the foot ii. Deep Fibular Nerve / Deep Peroneal Nerve - a sensorimotor nerve; from the dorsal divisions of L-5, S-1 & S-2 - supplies the 1st webspace and adjacent sides of the 1st and 2nd toes iii. Lateral Cutaneous Nerve of the Calf - a sensory nerve; from the dorsal divisions of L-5, S-1 & S-2 - supplies the proximal 2/3 of the lateral aspect of the leg iv. Sural Communicating Nerve - a sensory nerve; from the dorsal divisions of S-1 & S-2 - passes inferiorly and joins the sural nerve b. Tibial Nerve - a sensorimotor nerve; from ventral divisions of L-4, L-5, S-1, S-2 & S-3 - the medial portion of the sciatic nerve - passes inferiorly through the leg, posterior to the medial malleolus and divides into its terminal branches, the medial and lateral plantar nerves, prior to entering the foot through the porta pedis - provides muscular innervation in the knee and leg, articular innervation to the knee and ankle joints and the following cutaneous nerve branches: i. Sural Nerve - a sensory nerve; from the ventral divisions of S-1 & S-2 - supplies small area of the posterior leg, posterolateral aspect of the ankle, the lateral aspect of the foot, and the lateral ½ of the fifth toe aa. Lateral Calcaneal Nerve - a sensory nerve; from dorsal and ventral divisions of S-1 & S-2 because the sural communicating nerve joins the sural nerve - supplies the lateral ½ of the calcaneal region ii. Medial Calcaneal Nerve - a sensory nerve; from the ventral divisions of S-1 & S-2 - pierces the flexor retinaculum to supply the medial ½ of the calcaneal region 5. Posterior Femoral Cutaneous Nerve - a sensory nerve; from the dorsal divisions of S-1 and S-2, and ventral divisions of S-2 and S-3 - dorsal divisions lie close to the inferior gluteal nerve divisions, ventral divisions lie close to the pudendal nerve divisions - exits the pelvis via the greater sciatic foramen with the sciatic nerve and passes distally to the knee, anterior to the deep fascia, to supply cutaneous innervation to the posterior aspects of the thigh and the calf

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pelvic region, sacral plexus, posterior femoral cutaneous nerve, con’t a. Inferior Cluneal Nerves - from the dorsal divisions of S-1 & S-2, and ventral divisions of S-2 & S-3 - small branches of the posterior femoral cutaneous nerve that arise near the exit point from the pelvis and provide cutaneous supply to the inferior gluteal region 6. Perforating Cutaneous Nerve - a sensory nerve; from the dorsal divisions of S-2 and S-3 - exits the pelvis by piercing the sacrotuberous ligament to supply cutaneous innervation to the small area of the inferior medial aspect of the buttock and the medial gluteal fold 7. Pudendal Nerve - a sensorimotor nerve; from the ventral divisions of S-2, S-3 and S-4 - exits the pelvis via the inferomedial part of the greater sciatic foramen, passes posterior to the sacrospinous ligament and re-enters the pelvis via the lesser sciatic foramen - supplies motor innervation to structures of the urogenital triangle and sensory innervation to the reproductive organs 8. nerve to obturator internus and superior gemellus muscles - a motor nerve; from the ventral divisions of L-5, S-1 and S-2 - exits the pelvis via the greater sciatic foramen and reenters the pelvis via the lesser sciatic foramen, with the pudendal nerve - supplies motor innervation to obturator internus and superior gemellus mm. 9. nerve to quadratus femoris and inferior gemellus muscles - a sensorimotor nerve; from the ventral divisions of L-4, L-5 and S-1 - exits the pelvis via the greater sciatic foramen - supplies motor innervation to quadratus femoris and inferior gemellus muscles, and articular innervation to the hip joint 10. Pelvic Splanchnic Nerves (not pictured) - parasympathetic fibers from S-2, S-3 and S-4 - supply the pelvic viscera (organs which can't be removed without resection bladder, rectum and internal reproductive organs) C. Coccygeal Plexus - formed by the ventral rami of S-4, S-5 and Co-1 - provide muscular and cutaneous innervation 1. Sacral Muscular Branches - from S-4 - supplies motor innervation to levator ani, coccygeus and external anal sphincter mm. 2. Cutaneous Branches - from all rami - supply sensory innervation to the skin over the coccyx and posterior to anus

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III. PELVIC VASCULATURE A. Arterial 1. Aorta - abdominal aorta bifurcates at vertebral level L-4 into 2 common iliac arteries (one for each lower limb) a. Median Sacral Artery / Middle Sacral Artery - a small branch from the dorsal aortic surface just proximal to the bifurcation - small branches pass to the rectum 2. Common Iliac Artery - sends branches to psoas major and iliacus muscles - bifurcates into the internal and external iliac arteries at vertebral level L-5 3. External Iliac Artery - larger branch of the common iliac artery - follows the psoas major muscle (also sends a branch to this muscle and to the iliacus muscle) and enters the thigh deep to the midpoint of the inguinal ligament where it becomes the femoral artery in the thigh a. Deep Circumflex Iliac Artery - arises laterally just prior to the inguinal ligament and passes superolaterally along the deep side of the ligament to reach the anterior superior iliac spine - anastomoses with the iliolumbar and superior gluteal arteries (branches of internal iliac artery) b. Inferior Epigastric Artery - arises anteriorly just prior to the inguinal ligament and medial to the deep circumflex iliac artery - passes superiorly along the abdominal wall and anastomoses with the superior epigastric artery
This anastomosis can provide collateral circulation between the subclavian artery and the external iliac artery. 4. Internal Iliac Artery - the medial and smaller branch of the common iliac artery - divides into anterior and posterior trunks at the greater sciatic foramen - supplies the psoas major and iliacus muscles a. Anterior Trunk of the Internal Iliac Artery - passes toward the ischial spine - usually appears to be the direct continuation of the internal iliac artery i. Obturator Artery - most lateral branch of the anterior trunk - exits the pelvis via the obturator canal with the obturator nerve - may be a branch from the internal iliac artery or sometimes (40%) a branch of the external iliac artery at the pelvic brim

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pelvic region, vessels, obturator artery, con’t aa. Anterior Branch of Obturator Artery - the larger terminal branch - supplies medial compartment thigh and obturator externus muscles bb. Posterior Branch of Obturator Artery - the other terminal branch - supplies medial compartment thigh muscles, and posterior compartment thigh muscles proximally at the ischial tuberosity - provides branches to the hip joint - anastomoses with the anterior branch and the inferior gluteal artery ii. Inferior Gluteal Artery - terminal division of the anterior trunk - exits pelvis via greater sciatic foramen, usually intermediate to the ventral rami of S-1 & S-2 or the ventral rami of S-2 & S-3 - before its exit, supplies piriformis muscle - after its exit, supplies gluteal region muscles and the sciatic nerve - anastomoses near hip joint with superior gluteal, obturator, internal pudendal and medial femoral circumflex arteries iii. Internal Pudendal Artery - terminal branch of the anterior trunk - exits the pelvis via the greater sciatic foramen and re-enters the pelvis via the lesser sciatic foramen - supplies the sacral plexus, obturator internus muscle, piriformis muscle and external genitalia iv. Pelvic Branches (not pictured) - branches that supply pelvic organs and structures b. Posterior Trunk of Internal Iliac Artery i. Iliolumbar Artery - arises anterior to the sacroiliac joint and passes superolaterally in the pelvis - anastomoses near iliac crest with the superior gluteal, the deep circumflex iliac and the lateral femoral circumflex arteries ii. Lateral Sacral Artery - terminal branch of the posterior trunk, arises within the true pelvis - supplies the sacral ala iii. Superior Gluteal Artery - largest branch from either trunk, usually - appears as the direct continuation of the posterior trunk, usually - exits pelvis via greater sciatic foramen, usually intermediate to the lumbosacral trunk and the S-1 ventral ramus - before its exit, supplies the piriformis and obturator internus muscles - after its exit, supplies the 3 gluteal muscles (named gluteal) - anastomoses at hip joint with deep circumflex iliac, medial and lateral femoral circumflex, and inferior gluteal arteries 59

pelvic region, vessels, con’t B. Venous - small arteries have paired vena comitantes - large arteries have a single vein (vena comitans) - will draw veins only a few times as they usually follow the course of the arteries 1. Inferior Vena Cava - begins at the union of the common iliac veins at vertebral level L-5 - usually travels superiorly at the right of abdominal aorta and the spinal column 2. Common Iliac Vein - begins at the union of the internal and external iliac veins at the pelvic brim - the right one is shorter and posterolateral to its artery - the left one is longer and posteromedial to its artery 3. External Iliac Vein - begins posterior to the inguinal ligament - lies medial to the artery distally and posterior to the artery proximally - vena comitantes of the deep circumflex iliac and inferior epigastric arteries enter near the origin (at the inguinal ligament level) 4. Internal Iliac Vein (not pictured) - begins at the superior margin of the greater sciatic foramen where the vena comitantes of the arteries of the anterior and posterior trunks unite - generally lies posterior to the artery C. Lymphatics - deep lymph nodes associated with the pelvis - collect lymph fluid from the areas drained by the respective veins 1. External Iliac Lymph Nodes - lie along the external iliac veins - receive fluid from the superficial and deep inguinal lymph nodes, the iliac fossa and the anterior part of the capsule of the hip joint 2. Internal Iliac Lymph Nodes - lie along the internal iliac veins - receive fluid from the pelvic viscera, the gluteal region and the posterior, medial and lateral aspects of the hip joint 3. Common Iliac Lymph Nodes - lie along common iliac veins - receive fluid from the internal and external iliac lymph nodes 4. Lumbar Lymph Nodes - lie along the inferior vena cava on the posterior abdominal wall - receive fluid from the common iliac lymph nodes

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pelvic region, vessels, lymphatics, con’t 5. Lumbar Trunks (not pictured) - large vessels formed by the joining of efferent vessels of the lumbar lymph nodes - receive fluid from the lumbar lymph nodes 6. Cisterna Chyli - a dilated area that lies anterior to the vertebral bodies of L-1 and L-2 - receives fluid from the lumbar trunks - empties into the thoracic duct which returns the lymph fluid to the systemic circulation

GLUTEAL REGION Much of the neurovascular supply to the gluteal region passes through the greater sciatic foramen. The muscles of the gluteal region function generally to extend, abduct and laterally rotate the hip and thigh. I. MUSCLES of the gluteal region A. Superficial Layer 1. Gluteus Maximus Muscle - the large muscle of the buttock - the primary extensor of the thigh - covered by a dense layer of adipose tissue with many strong septae called the gluteal fascia, which gives this region its shape - covers the other muscles of this region; six small muscles which together are fan-shaped O: external iliac ala posterior to posterior gluteal line, the posterior iliac crest, the external surfaces of the sacrum and coccyx, and the sacrotuberous ligament (also gluteal fascia) I: gluteal tuberosity of the femur and the posterosuperior iliotibial tract - passes obliquely from superomedial to inferolateral A: extends and laterally rotates the thigh NS: inferior gluteal nerve; dorsal divisions of ventral rami L-5, S-1 & S-2 AS: superior gluteal artery, inferior gluteal artery and the perforating branches of the profunda femoris artery a. Bursae (of the gluteus maximus muscle) - there are 3 bursae associated with the gluteus maximus muscle i. Trochanteric Bursa - located intermediate to the gluteus maximus muscle and the lateral aspect of the greater trochanter of the femur - inflammation of this bursa is called bursitis of the hip - painful with extension or lateral rotation of thigh when inflamed

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gluteal region, muscles, bursae of gluteus maximus muscle, con’t ii. Ischial Bursa - located intermediate to the gluteus maximus muscle and the ischial tuberosity - inflammation of this bursa is associated with prolonged sitting in the tailor position (Indian-style or cross-legged) or from riding horses/bicycles - inflammation of this bursa is called weaver's bottom, sometimes called saddle sore - painful with sitting iii. Gluteofemoral Bursa - located intermediate to the gluteus maximus muscle and the vastus lateralis muscle, just inferior to the gluteal tuberosity of the femur b. Intramuscular Injections - injections into the buttock must be placed so as to miss the major neurovascular structures of this region, especially the sciatic nerve - each buttock is divided into quadrants - the injection is given in the superolateral / upper outer quadrant B. Intermediate Layer 1. Gluteus Medius Muscle - located deep to the gluteus maximus muscle - extends superior to the proximal edge of gluteus maximus muscle near the center of gluteus maximus muscle - the primary abductor of the thigh O: external iliac ala intermediate to the anterior and posterior gluteal lines I: lateral aspect of the greater trochanter - passes inferolaterally A: abducts the thigh; aids with both medial and lateral rotation of the thigh NS: superior gluteal nerve; dorsal divisions of ventral rami L-4, L-5 & S-1 AS: superior gluteal artery a. Bursa (of the gluteus medius muscle) - this bursa is located intermediate to the gluteus medius muscle and the superior aspect of the femoral greater trochanter - pain from this bursa is associated with hip joint abduction and palpation C. Deep Layer - gluteal muscles 1. Gluteus Minimus Muscle - the smallest of the 3 gluteal muscles O: iliac ala intermediate to the anterior and inferior gluteal lines, and the superior edge of the greater sciatic notch I: anterior aspects of the greater trochanter and the hip joint capsule - passes inferiorly A: abduction and medial rotation of the thigh (medial rotation because the insertion of the muscle is anterior to the hip joint axis) NS: superior gluteal nerve; dorsal divisions of ventral rami L-4, L-5 & S-1 AS: superior gluteal artery 62

gluteal region, muscles, con’t 2. Piriformis Muscle - an important anatomic landmark as it aids in the identification of other structures in this region O: pelvic surface of the sacrum (S-2, S-3, S-4) I: superior aspect of the greater trochanter - passes laterally, exiting the pelvis via the greater sciatic foramen A: lateral rotation of the thigh; assists in abduction and extension of the thigh NS: dorsal division of S-2 ventral ramus, (nerve to piriformis muscle) AS: superior and inferior gluteal arteries 3. Superior Gemellus Muscle - a small muscle situated inferior to piriformis muscle and deep to some neurovascular structures - its muscle belly lies adjacent to the inferior gemellus muscle belly O: ischial spine and superior edge of lesser sciatic notch I: anterior fossa (unnamed) at the medial aspect of the greater trochanter, with the tendons of obturator internus and inferior gemellus muscles - passes laterally A: lateral rotation of the thigh NS: nerve to obturator internus and superior gemellus muscles, from the sacral plexus; ventral divisions of ventral rami L-5, S-1 and S-2 AS: inferior gluteal artery 4. Inferior Gemellus Muscle - its muscle belly lies adjacent to the superior gemellus muscle belly O: inferior margin of lesser sciatic notch and superior border of ischial tuberosity I: anterior fossa (unnamed) at the medial edge of the greater trochanter, with the tendons of superior gemellus and obturator internus muscles - passes laterally A: lateral rotation of the thigh NS: nerve to inferior gemellus muscle and quadratus femoris muscle, from the from the sacral plexus; ventral divisions of ventral rami L-4, L-5 & S-1 AS: medial femoral circumflex artery 5. Obturator Internus Muscle - the tendon is generally deep and intermediate to the gemelli muscles O: pelvic surfaces of the obturator foramen and obturator membrane I: anterior fossa (unnamed) on the medial edge of the greater trochanter, with the gemelli muscles - passes posterolaterally to exit the pelvis via the lesser sciatic foramen, then angles anteriorly around the lesser sciatic notch A: external rotation of the thigh; extension and abduction of the thigh when the hip is flexed NS: nerve to obturator internus and superior gemellus muscles, from the sacral plexus; ventral divisions of ventral rami L-5, S-1 and S-2 AS: superior gluteal and internal pudendal arteries 63

gluteal region, muscles, con’t 6. Quadratus Femoris Muscle - rectangular shaped muscle, the most inferior of the gluteal muscles O: external border (of the posterior squared part) of the ischial tuberosity I: quadrate tubercle of the femur - passes directly lateral A: lateral rotation of the thigh NS: nerve to inferior gemellus muscle and quadratus femoris muscle, from the sacral plexus; ventral divisions of ventral rami L-4, L-5 and S-1 AS: medial femoral circumflex artery 7. Obturator Externus Muscle - its tendon can be found deep to the quadratus femoris muscle in the gluteal region; its origin may be seen deep to the pectineus muscle at the anterosuperior thigh region O: external surfaces of the obturator foramen and the obturator membrane I: trochanteric fossa of the femur - passes posterolaterally around the inferior surface of the femoral neck (a spiral course) A: lateral rotation of the thigh (due to insertion posterior to the hip joint axis); aids in flexion and adduction of the thigh (due to its course around the femoral neck) NS: obturator nerve; ventral divisions of ventral rami L-2, L-3 and L-4 - the only gluteal region muscle to receive innervation from the lumbar plexus AS: obturator artery

II. NERVES of the gluteal region A. Pudendal Nerve - from the ventral divisions of ventral rami S-2, S-3 and S-4 - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle - passes posterior to the sacrospinous ligament - reenters the pelvis via the lesser sciatic foramen B. Nerve to Obturator Internus and Superior Gemellus Muscles - from the ventral divisions of ventral rami L-5, S-1 and S-2 - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle - it lies lateral to the pudendal nerve as it passes posterior to the sacrospinous ligament and sends a branch laterally to supply the superior gemellus m. - it then, reenters the pelvis via the lesser sciatic foramen to innervate the obturator internus muscle

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gluteal region, nerves, con't C. Posterior Femoral Cutaneous Nerve - from the dorsal divisions of ventral rami S-1 and S-2, and ventral divisions of ventral rami S-2 and S-3 - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle and usually posterior to the sciatic nerve; the main branch lies within the fascia on the deep surface of gluteus maximus muscle, then passes inferiorly through the posterior thigh, deep to or within the fascia lata to the inferior knee region - the cutaneous branches penetrate the fascia lata along this course 1. Inferior Cluneal Nerves (not pictured) - cutaneous branches of the posterior femoral cutaneous nerve that supply a portion of the gluteal region skin - arise near the proximal end and pass along the deep surface of the gluteus maximus muscle, then pass around its inferior edge to the skin D. Nerve to Quadratus Femoris and Inferior Gemellus Muscles - from the ventral divisions of ventral rami L-4, L-5 and S-1 - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle (usually located anterior to the sciatic nerve) - passes anterior to the obturator internus tendon and the gemelli muscles where it sends a branch to the inferior gemellus muscle; it continues inferiorly and sends branches to the hip joint and the deep side of the quadratus femoris muscle E. Sciatic Nerve - the largest nerve in the body, the primary formation of the sacral plexus - from dorsal divisions of ventral rami L-4, L-5, S-1 and S-2, and ventral divisions of ventral rami L-4, L-5, S-1, S-2 & S-3 - exits the pelvis via the greater sciatic foramen, deep to the gluteus maximus muscle and usually inferior to the piriformis muscle - passes inferiorly into the thigh usually midway between the ischial tuberosity and the greater trochanter, and continues inferiorly along the posteromedial aspect of the thigh, deep to the muscles to the level of the knee region where it normally divides variation: - the common fibular part may exit the pelvis either superior to or through the piriformis muscle belly and then course with the tibial part - when this occurs, the sciatic nerve has split into its component parts already F. Inferior Gluteal Nerve - from dorsal divisions of ventral rami L-5, S-1 and S-2 - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle - passes directly posterior and into the gluteus maximus muscle to innervate it G. Superior Gluteal Nerve - from dorsal divisions of ventral rami L-4, L-5 and S-1 - exits the pelvis via the greater sciatic foramen, superior to the piriformis muscle - passes laterally, intermediate to the gluteus medius and gluteus minimus muscles; it supplies both of them and continues anterolaterally to supply the tensor fascia lata muscle (a thigh muscle in this course)

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gluteal region, nerves, con't H. Perforating Cutaneous Nerve (not pictured) - from dorsal divisions of ventral rami S-2 and S-3 - exits the pelvis by piercing the sacrotuberous ligament, usually near the sacrum - may be a direct course or pass within the ligament for a short distance - passes inferiorly around the distomedial edge of the gluteus maximus muscle to innervate a small area of skin at the inferomedial gluteal region

III. ARTERIES A. Internal Pudendal Artery - from the anterior trunk of internal iliac artery - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle, usually lies intermediate to the pudendal nerve and the nerve to obturator internus and superior gemellus muscles - passes posterior to the sacrospinous ligament - reenters the pelvis via the lesser sciatic foramen, then supplies obturator internus m. B. Inferior Gluteal Artery - from the anterior trunk of internal iliac artery - before exiting the pelvis it supplies the piriformis, levator ani and coccygeus mm. - exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle - passes posterior, lateral and inferior to supply gluteal region structures - after exiting, it supplies gluteus maximus and superior gemellus muscles, the sciatic nerve and the hip joint C. Superior Gluteal Artery - from the posterior trunk of internal iliac artery - before exiting the pelvis it supplies piriformis and obturator internus muscles - exits the pelvis via the greater sciatic foramen, superior to the piriformis muscle - a superficial branch passes posterior to supply the gluteus maximus muscle - a deep branch passes lateral to supply the gluteus medius, gluteus minimus and tensor fascia lata muscles and the hip joint; travels with the superior gluteal n.

HIP JOINT The hip joint is the articulation between the acetabulum of the pelvis and the head of the femur. The acetabulum has contributions from the ilium, ischium and pubis. The hip joint is structurally a synovial spheroid joint and functionally a diarthrosis type of joint. The hip joint has motion in all three body planes, a triplanar joint. The movements available are flexion, extension, abduction, adduction, circumduction, internal rotation and external rotation.

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pelvic region, hip joint, con’t I. LIGAMENTS A. Extracapsular Ligaments / Extrinsic Ligaments - ligaments outside of the joint cavity - in general, spiral around the hip joint from posterior to anterior; therefore, are taut (tight) when the hip is extended, and limit extension of the hip joint anterior view 1. Iliofemoral Ligament / Ligament of Bigelow - attaches proximally to the inferior part of the anterior inferior iliac spine and the iliac part of the acetabular rim (lip) - passes distally as 2 bands - one of the strongest ligaments in the body a. upper band - attaches to the superior part of the intertrochanteric line b. lower band - attaches to the inferior part of the intertrochanteric line 2. Pubofemoral Ligament - attaches proximally to the pubic part of the acetabular rim and the lateral part of the superior pubic ramus - passes distally and blends with the capsule of the hip joint (medially) posterior view 1. Iliofemoral Ligament (upper band) - the posterosuperior fibers of this ligament can be seen from this view - these fibers pass anteriorly around the hip joint to insert on the superior part of the intertrochanteric line 2. Ischiofemoral Ligament - attaches proximally to the ischial part of the acetabular rim - passes superolaterally over the posterior surface of the hip joint to blend with the capsule of the hip joint at the femoral neck B. Intracapsular Ligaments / Intrinsic Ligaments - thickenings of the joint capsule or located within the joint cavity posterior view and frontal plane cross section view 1. Zona Orbicularis - the thickened constricted area of the capsule around the neck of the femur (the fibers are circularly oriented) - visible on the posteroinferior surface where extracapsular ligaments are less prominent - a ligament with no bony attachments - initially believed to hold the femoral head into the acetabulum, but it is not strong enough by itself 67

gluteal region, hip joint, intracapsular ligaments, con’t 2. Transverse Acetabular Ligament - attaches to the edges of the acetabular notch, at the margins of the lunate surface, converting it into the acetabular foramen for the passage of articular vessels 3. Ligamentum Capitis Femoris / Ligamentum Teres Femoris / Ligament of the Head of the Femur - attaches proximally to the margins of the acetabular notch and the transverse acetabular ligament within the acetabulum - passes along the acetabular fossa, which is covered with adipose tissue and attaches distally to the margins of the fovea capitis femoris - this is a weak ligament which transmits the artery to the head of the femur - important in infants (under age 3 years) as the artery is the primary supply to the femoral head until this age C. Other Structures 1. Capsule - the fibrous joint capsule attaches proximally to the exterior rim of the acetabulum - distally the capsule attaches to the neck of the femur; anteriorly to the inferior margin of the femoral neck at the intertrochanteric line and posteriorly to the mid-region of the neck (only the proximal one-half of the femoral neck is within the capsule posteriorly) - the extrinsic ligaments are in the same location so the femoral neck on the posterior side is covered only about ½ of the distance a. Zona Orbicularis – described above b. Retinacula - bundles of longitudinal capsular fibers that reflect superiorly along the femoral neck after having reached the inferior margin of the capsular limits - provide for passage of blood vessels from the capsule and synovial lining to the head of the femur; main area for passage of vessels to nourish the head and neck of the femur after 3 years of age 2. Acetabular Labrum / Glenoid Labrum - a pad of fibrocartilage that lies along and attaches to the acetabular rim - function: to deepen the joint which provides a better fit between the bone ends 3. Synovium (dashed lines) - lines all of the structures contained within the joint capsule except the articular surfaces of the bones, so all intrinsic ligaments are extrasynovial - the synovium that lines the retinacula of the capsule are raised into folds through which the blood vessels pass

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gluteal region, hip joint, con’t 4. Arterial Supply to the Hip Joint a. Artery to the Ligamentum Capitis Femoris - a branch of the acetabular artery, after it passes into the acetabulum via the acetabular foramen, which then passes along the acetabular fossa - supplies the head of the femur, but is not the primary supply after age 3 years - the acetabular artery arises from the posterior division of the obturator artery b. Medial Femoral Circumflex Artery (not pictured) - the ascending branch passes along the femoral intertrochanteric crest and gives rise to branches which pass through the retinacula to supply the femoral head and neck - anastomose with branches in the femoral head c. Lateral Femoral Circumflex Artery (not pictured) - the ascending branch passes along the femoral intertrochanteric line and gives rise to branches which pass through the retinacula to supply the head and neck of the femur - anastomose with branches in the femoral head d. Superior Gluteal Artery (not pictured) - branches that arise from the deep branch and continue laterally and inferiorly to supply the hip joint e. Inferior Gluteal Artery (not pictured) - branch(es) which pass laterally and inferiorly to supply the piriformis and superior gemellus muscles then continue to the hip joint

HIP ANASTOMOSES The anastomoses around the hip allow alternate routes for blood flow to the area of the proximal extremity of the femur between the internal iliac artery and the femoral artery. I. TROCHANTERIC ANASTOMOSIS - provides the major blood supply to the head and neck of the femur, after age 3 years - is an arterial anastomosis around the femoral neck - branches pass within the retinacula of the capsule A. Superior Gluteal Artery - the deep branch passes intermediate to gluteus medius and minimus muscles and gives rise to an inferior branch which continues inferiorly to the hip joint area B. Inferior Gluteal Artery - the branch to the hip joint also normally supplies both the piriformis and superior gemellus muscles; (it courses intermediate to the gluteus maximus muscle and the smaller muscles of the gluteal region) 69

gluteal region, hip anastomoses, con’t C. Medial Femoral Circumflex Artery - the ascending branch which passes along the intertrochanteric crest of the femur D. Lateral Femoral Circumflex Artery - the ascending branch which passes along the intertrochanteric line of the femur II. CRUCIATE ANASTOMOSIS - located near the lesser trochanter of the femur A. Inferior Gluteal Artery - a branch of the one that supplies the hip joint B. Medial Femoral Circumflex Artery - the transverse branch which passes posteriorly around the femur at the junction of the proximal extremity and shaft C. Lateral Femoral Circumflex Artery - the transverse branch which passes anteriorly around the femur at the junction of the proximal extremity and shaft D. First Perforating of the Profunda Femoris Artery - passes posterolaterally near the inferior extent of the lesser trochanter

TOPIC #4

THIGH REGION Osteology of the Leg

I. PATELLA - commonly called the knee cap - is a sesamoid bone, largest sesamoid bone in body - articulates only with the femur - recognized by its roughly triangular shape - provides leverage for the quadriceps femoris muscle - base - the superior widened end - apex - the narrow (pointed) inferior end

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thigh region, leg osteology, con’t A. anterior view - this surface is roughened from the pull of the quadriceps femoris tendon - longitudinal ridges are called striae - this surface is also subcutaneous and easily palpated at the anterior aspect of of the knee region - subcutaneous means that the deep fascia attaches to this surface B. posterior view - most of this surface is smooth for articulation with the femoral condyles - the medial, lateral and superior edges are rough for attachment of the quadriceps femoris tendon - this surface has two facets which are separated by a vertical ridge 1. Lateral Facet - the deeper and usually larger facet - due to extra stress from the slight lateral angulation between the femur and the tibia - articulates with the lateral condyle of the femur 2. Medial Facet - the shallower and usually smaller facet - articulates with the medial condyle of the femur 3. Borders - all borders, superior, medial and lateral are roughened for ligamentous and tendinous attachment C. Ossification of the Patella - develops from a single or several centers of ossification - center(s) appear between 3 and 6 years of age and are fused by puberty - if centers do not fuse, get a bipartite patella

II. TIBIA - commonly called the shin bone - located on the medial side of the leg - recognized by the inferior medial projection known as the medial malleolus - articulates with the femur superiorly, the fibula laterally, both proximal and distal and the talus inferiorly - transfers the body weight from the femur to the talus anterior view A. Proximal Extremity - the superior end of the tibia - articulates on its superior surface with the distal extremity of the femur and laterally with the fibula

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thigh region, leg osteology, tibial proximal extremity, con’t 1. Medial Condyle - the flattened superior medial projection - larger than the lateral condyle - can be palpated at the medial aspect of the knee region 2. Lateral Condyle - the flattened superior lateral projection - projects farther lateral and posterior from the shaft of the tibia (as compared to the medial condyle) - can be palpated at the lateral aspect of the knee region a. Fibular Facet - on the inferior surface of the lateral condyle, posteriorly - for articulation with the fibular head 3. Intercondylar Eminence - the central superior projection 4. Tibial Tuberosity - large projection on the anterior surface - provides attachment for the patellar ligament/patellar tendon - easily palpated inferior to the patella 5. Tubercle of the Iliotibial Tract / Gerdy's Tubercle - projection of variable size located along the line that extends from the lateral edge of the tibial tuberosity to the lateral condyle - site of attachment of the iliotibial tract - can often be palpated, just lateral to the apex of the patella with the knee extended and the superior edge of the tibial tuberosity B. Shaft - from the tibial tuberosity, proximally to the fibular notch, distally - often divided into thirds (lengthwise) to aid in describing the origins and insertions of muscles 1. Anterior Border / Tibial Crest - the curved sharp anterior line on the shaft - can be palpated along the anterior aspect of the leg, usually near its midline - easiest if foot is not actively dorsiflexed 2. Medial Surface - the subcutaneous rounded surface that faces anteromedially - can palpate its entire length along the medial side of the leg 3. Interosseous Border / Lateral Border - the border that provides attachment for the interosseous membrane (between the tibia and fibula); intermediate to the lateral and posterior surfaces

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thigh region, leg osteology, tibia; shaft con’t 4. Lateral Surface / Extensor Surface - the slightly concave surface that faces laterally and is lateral to the tibial crest - for attachment of muscles C. Distal Extremity - rectangular in shape - articulates at its inferior surface with the talus at the ankle joint 1. Medial Malleolus - the inferior medial projection - is subcutaneous and easily palpated at the medial ankle region a. Talar Articular Facet - pear-shaped facet on the lateral surface of the medial malleolus - articulates with medial surface of talar body 2. Tibial Plafond (plafond = ceiling) - the inferior articular surface - rectangular in shape - is continuous with the articular facet of the medial malleolus - articulates with the talar body posterior view A. Proximal Extremity 1. Medial Condyle - described above a. groove for insertion of semimembranosus muscle - horizontal groove on the posterior surface near the articular facet of the condyle b. superior articular surface - smooth superior surface that articulates with the femoral medial condyle 2. Lateral Condyle - described above a. Fibular Facet - described above b. superior articular surface - smooth superior surface that articulates with the femoral lateral condyle 3. Intercondylar Eminence - described above B. Shaft of the tibia (the posterior surface) 73

1. Popliteal Line / Soleal Line - extends from the fibular facet superolaterally to the medial border at the junction of the proximal and middle thirds - for muscular attachment 2. Vertical Line - begins near the middle of the soleal line and extends inferiorly to the inferior one-third - separates muscle attachments - may not be distinct 3. Nutrient Foramen - located inferior to the popliteal line and usually lateral to the vertical line - the largest in the body - projects inferiorly as most growth of lower limb in length is at the knee C. Distal Extremity 1. Medial Malleolus - described above a. Groove for Tibialis Posterior and Flexor Digitorum Longus Tendons - longitudinal depression on the posterior surface of the medial malleolus 2. Posterior Process - posterior lateral prominence of distal tibial extremity - sometimes called the third malleolus a. Groove for Flexor Hallucis Longus Tendon - longitudinal depression over the posterior process of the tibia 3. Fibular Notch - large triangular depression on the lateral surface of the distal extremity - provides attachment sites for ligaments - articulates with the fibula at the tibiofibular syndesmosis superior view A. Proximal Extremity 1. Articular Facet of the Medial Condyle - the larger ovoid facet - for articulation with the medial femoral condyle 2. Articular Facet of the Lateral Condyle - the smaller circular facet - for articulation with the lateral condyle of the femur 3. Intercondylar Eminence - described above

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thigh region, leg osteology, tibia, con’t 4. Anterior Intercondylar Fossa - a depression from the intercondylar eminence to the anterior surface of the tibia, intermediate to the medial and lateral condyles - wider anteriorly - provides attachment for soft tissue structures 5. Posterior Intercondylar Fossa - a depression from the intercondylar eminence to the posterior surface of the tibia, intermediate to the tibial medial and lateral condyles - wider posteriorly - provides attachment for soft tissue structures 6. Tibial Tuberosity - described above

medial view A. Distal Extremity 1. Medial Malleolus - described above a. Anterior Colliculus - anterior projection at the inferior edge of the medial malleolus - for ligamentous attachment b. Posterior Colliculus - posterior projection at the inferior edge of the medial malleolus - for ligamentous attachment c. Groove for Tibialis Posterior and Flexor Digitorum Longus Tendons - described above 2. Posterior Process - described above a. Groove for Flexor Hallucis Longus Tendon - described above - may cross posterior process or lie intermediate to the medial malleolus and the posterior process

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thigh region, leg osteology, distal tibia, con’t inferior view A. Distal Extremity 1. Medial Malleolus - described above a. Anterior Colliculus - described above b. Posterior Colliculus - described above c. Groove for Tibialis Posterior and Flexor Digitorum Longus Tendons - described above d. Medial Malleolar Facet - pear-shaped articular facet on the lateral surface of the medial malleolus - articulates with the talar body, medially 2. Posterior Process - described above a. Groove for Flexor Hallucis Longus Tendon - described above 3. Fibular Notch - described above 4. Tibial Plafond - described above

Ossification of the tibia - the tibia normally has 3 centers of ossification 1. Primary Center - in the shaft; appears near the 7th fetal week 2. Secondary Centers - one in each extremity - the proximal center appears by birth - the distal center appears by age 1 year - these fuse in reverse order between ages 15 and 18 years - occasionally there are also centers in the tibial tuberosity and the medial malleolus

III. FIBULA - commonly called the calf bone - carries 15% of body weight - very important for ankle stability as will not get adequate reduction (stable alignment) of an ankle fracture without proper alignment of the fibula - articulates with the tibia (proximally and distally) and with the talus (distomedially) - recognized by its long slender shape 76

thigh region, leg osteology, fibula, con’t medial view A. Proximal Extremity / head - quadrate in shape - subcutaneous and easily palpated just lateral to the lateral condyle of the tibia - an important landmark because the common fibular nerve passes superficially (from posterosuperior to anteroinferior) around the fibular head and neck at this point, and can be damaged through physician error 1. Articular Facet (of the head of the fibula) - roughly circular in shape - for articulation with the fibular facet on the lateral condyle of the tibia 2. Apex of the Fibula / Styloid Process of the Fibula - a small blunt superoposterolateral projection - for ligamentous attachment B. Shaft - the borders and surfaces of the fibular shaft spiral externally from proximal to distal 1. Anterior Border - sharp edge that begins superiorly at the head (on the anterior side) and continues distally (on the lateral side) - at the distal extremity, it splits and forms the smooth lateral surface 2. Interosseous Border - found immediately posterior (and medial) to the anterior border - extends from the head to the roughened triangular area at the distal extremity - the interosseous membrane attaches to this border; fibers pass inferiorly from tibia to fibula which allows a small amount of separation of the fibula from the tibia as the fibula externally translates 3. Medial Surface / Extensor Surface - the narrow area intermediate to the anterior and interosseous borders that extends from the head to the lateral malleolus - positioned more anterior and provides sites of attachment for muscles 4. Crista Medialis / Medial Crest - an oblique line on the posterior surface that extends from the head to the shaft’s distal 1/3 - separates muscular attachments 5. Posterior Surface / Flexor Surface - a large surface located posterior to the interosseous border - the crista medialis divides this surface and the part anterior to this crest is referred to as the medial part of the posterior (posteromedial) surface - for muscular attachment, foot plantar flexors a. Nutrient Foramen - normally on the posterolateral surface, posterior to the medial crest 77

thigh region, leg osteology, fibular shaft, con’t C. Distal Extremity / Lateral Malleolus - situated more distal and more posterior than the medial malleolus in a living being (in anatomic position) 1. Malleolar Articular Facet - large triangular surface for articulation with the talar body - the medial surface 2. Lateral Malleolar Fossa / Fibular Fossa - a deep fossa situated posterior to the facet - for ligamentous attachment 3. Lateral Malleolar Sulcus - a shallow groove on the posterior border of the lateral malleolus - occasionally is flat or convex - for passage of tendons, foot everters lateral view A. Proximal Extremity 1. Apex / Styloid Process of Fibula - described above B. Shaft 1. Anterior Border - described above 2. Lateral Surface / Fibular Surface / Peroneal Surface - immediately posterior to the anterior border (on the lateral side) - in a more anterior direction at the superior end and a more posterior direction at the inferior end - is palpable distally - for muscular attachment, foot everters 3. Posterior Border - separates lateral and posterior surfaces C. Distal Extremity / Lateral Malleolus 1. Lateral Malleolar Sulcus - described above 2. Summit of the Lateral Malleolus - rounded distal end - for ligamentous attachment - sometimes avulsed (fracture where pulled off) with ankle injuries 78

thigh region, leg osteology, fibula, con’t Ossification - the fibula normally ossifies from 3 centers of ossification A. Primary Center - in the shaft appears during the 8th fetal week B. Secondary Centers - one in each extremity - the distal extremity center appears during the first year - the proximal extremity center appears during the third year - these centers fuse in the same order between 15 and 19 years of age (puberty) - most long bone secondary centers of ossification fuse opposite to their order of appearance Tibiofibular Torsion - Tibiofibular torsion changes from birth to adulthood. This is measured as the axis of the malleoli / transmalleolar axis relative to the plane of the tibial condyles. At birth, this angle is zero degrees. It increases to 18 to 23 degrees externally rotated. This adult value is usually obtained by age 6 years. The clinical measurement is called malleolar position.

THIGH REGION - MUSCLES I. POSTERIOR COMPARTMENT The muscles of the posterior compartment of the thigh are hip and thigh extensors as well as knee and leg flexors. They act on two joints because they cross two joints. However, they generally can not act effectively on both joints simultaneously. These muscles are innervated by the sciatic nerve. Arterial supply is from the perforating arteries of profunda femoris, the inferior gluteal artery and the popliteal artery. A. Superficial Layer 1. Biceps Femoris Muscle, long head - one muscle with 2 heads of origin, very difficult to see both on one picture O: posteroinferomedial ischial tuberosity (squared posterior part); shared with semitendinosus muscle I: lateral aspect of the fibular head and the anterior edge of the lateral tibial condyle; shared with short head of biceps femoris muscle - muscle passes inferiorly, then angles laterally at the knee region - can palpate the tendon at the posterolateral knee region with resisted contraction A: extends the thigh; flexes and laterally rotates the leg NS: tibial part of sciatic nerve AS: profunda femoral perforating arteries, inferior gluteal and popliteal arteries 79

thigh region, muscles, posterior compartment, con’t 2. Semitendinosus Muscle - named for it's long, slender, tendon-like shape O: posteroinferomedial area of the ischial tuberosity; shared with the long head of biceps femoris muscle I: proximal medial shaft of the tibia - forms part of the pes anserinus (a tendinous structure) - passes inferiorly, then angles medially at the knee region - can palpate the tendon at the posteromedial knee region with resisted contraction - the more prominent tendon in this area, due to a more posterior position A: extends the thigh; flexes and medially rotates the leg NS: tibial part of sciatic nerve AS: profunda femoral perforating arteries, inferior gluteal and popliteal arteries B. Deep Layer 1. Biceps Femoris Muscle, Short Head O: lateral lip of the linea aspera (inferior 2/3) and the lateral supracondylar line (also the posterior femoral intermuscular septum) I: lateral aspect of the head of the fibula and the lateral condyle of the tibia; shared with the long head of biceps femoris muscle - passes inferolaterally and blends with the long head of the biceps femoris m. A: flexes and laterally rotates the leg NS: common fibular part of sciatic nerve AS: profunda femoral perforating arteries and popliteal artery 2. Semimembranosus Muscle - named for its superior membrane-like part - located anteromedial to the semitendinosus muscle O: posterosuperolateral part of the ischial tuberosity (squared posterior part) I: groove for semimembranosus muscle (on the posterior aspect of the medial tibial condyle) and the posterior knee joint as the oblique popliteal ligament and the fascia over the popliteus muscle (at the proximoposterior tibia) - passes inferiorly and turns sharply lateral at the posteromedial aspect of the knee region A: extends the thigh; flexes and medially rotates the leg NS: tibial part of sciatic nerve AS: profunda femoral perforating arteries, inferior gluteal and popliteal arteries

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thigh region, muscles, posterior compartment, con’t C. Hamstring Muscles - the three muscles of the posterior compartment of the thigh are collectively known as the hamstring muscles / hamstring group - O: the ischial tuberosity - A: extend the thigh and flex the leg - NS: sciatic nerve 1. Biceps femoris Muscle, long head 2. Semitendinosus Muscle 3. Semimembranosus Muscle

II. ANTERIOR COMPARTMENT MUSCLES The muscles of the anterior compartment of the thigh are primarily knee and leg extensors. Two of these muscles also cross the hip joint and as such have some action at this joint. Generally, these muscles are innervated by the femoral nerve. Arterial supply is primarily from branches of the femoral, profunda femoris and popliteal arteries. A. Superficial Layer 1. Tensor Fascia Lata Muscle - small muscle at lateral aspect of thigh O: lateral lip of the iliac crest, anterior to iliac tubercle (and fascia lata) I: iliotibial band which attaches at Gerdy's tubercle - courses inferiorly along the lateral aspect of the thigh A: flex and abduct the thigh, This stabilizes the hip during gait.; extend the leg, This stabilizes the knee during gait. NS: superior gluteal nerve AS: lateral femoral circumflex artery and superior gluteal artery 2. Sartorius Muscle - the longest muscle in the body; it’s strap-like (flat with constant width) O: anterior superior iliac spine (and fascia lata) I: proximal medial shaft of the tibia - forms part of the pes anserinus - courses inferiorly from the anterolateral aspect of the thigh to the posteromedial aspect of the knee A: flex and laterally rotate the thigh; flex the leg all combined is the tailor position NS: femoral nerve AS: femoral artery

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thigh region, muscles, anterior compartment, superficial layer, con’t B. Intermediate Layer - anterior compartment thigh muscles 1. Rectus Femoris Muscle O: Straight Head / Anterior Head - anterior inferior iliac spine Reflected Head / Posterior Head - iliac part of acetabular rim, externally I: base of the patella forming part of the quadriceps tendon, and then to the tibial tuberosity via the patellar tendon - muscle belly is easily palpated during muscular contraction A: extend the knee; assist with flexion of thigh NS: femoral nerve AS: descending branch of lateral femoral circumflex artery C. Deep Layer 1. Vastus Intermedius Muscle - directly deep to the rectus femoris muscle O: superior 2/3 of the femoral shaft (anterior and lateral surfaces) I: base of the patella forming part of the quadriceps tendon, and the tibial tuberosity via the patellar tendon A: extends the leg NS: femoral nerve AS: descending branch of lateral femoral circumflex artery 2. Vastus Lateralis Muscle O: superior intertrochanteric line, the anterior and inferior greater trochanter, the lateral edge of the gluteal tuberosity, and the superior lateral lip of the linea aspera I: lateral border of the patella forming part of the quadriceps tendon, and then tibial tuberosity via the patellar tendon - muscle fibers pass inferiorly and circularly (internally) around the femur - muscle belly is easily palpated along the anterolateral aspect of the thigh during muscular contraction A: extend the leg; pull the patella laterally NS: femoral nerve AS: descending branch of lateral femoral circumflex artery

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thigh region, anterior compartment, con’t 3. Vastus Medialis Muscle O: inferior intertrochanteric line, the spiral line, the medial lip of the linea aspera and the superior medial supracondylar line I: medial border of the patella forming part of the quadriceps tendon, and then tibial tuberosity via the patellar tendon - muscle fibers pass inferiorly and circularly (externally) around the femur - muscle belly is easily palpated along the anteromedial aspect of the thigh during muscular contraction A: extend the leg; pull the patella medially NS: femoral nerve AS: femoral, profunda femoris, and superior medial genicular arteries 4. Articularis Genu Muscle - a very small muscle - lies deep to the inferior part of the vastus intermedius muscle O: distal anterior shaft of the femur I: posterior aspect of the suprapatellar bursa / the superior extension of the capsule of the knee joint A: tense the knee joint capsule / suprapatellar bursa during extension to prevent impingement of the capsule NS: femoral nerve AS: superior medial genicular artery D. Quadriceps Femoris Muscle - four of the anterior compartment thigh muscles, considered as one - they usually act together - Together they form the quadriceps tendon. The quadriceps tendon attaches the quadriceps femoris muscle to the patella. The quadriceps tendon also envelopes the patella and forms the patellar tendon which inserts onto the tibial tuberosity. - the patellar tendon is also called the patellar ligament or ligamentum patellae - I: base of patella, then the tibial tuberosity through the patellar tendon - A: extend the leg; aid in flexion of the hip - NS: femoral nerve 1. 2. 3. 4.

Rectus Femoris Muscle Vastus Medialis Muscle Vastus Lateralis Muscle Vastus Intermedius Muscle

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thigh region, muscles, con’t III. MEDIAL COMPARTMENT THIGH These muscles are the adductor group. They adduct the hip and thigh. One of these muscles also crosses the knee joint and has some action there. These muscles are primarily innervated by the obturator nerve. Arterial supply is from the obturator, profunda femoris and popliteal arteries. A. Anterior Layer 1. Pectineus Muscle O: pecten pubis (from the pubic tubercle to the iliopectineal eminence) I: pectineal line of the femur - courses posteroinferolaterally (and crosses the obturator externus muscle) A: adduct and flex the thigh NS: femoral nerve AS: obturator artery and medial femoral circumflex artery 2. Adductor Longus Muscle O: anterior pubic body (inferior to the pubic crest and lateral to the pubic symphysis) I: medial lip of the linea aspera (middle 1/3) - courses posteroinferolaterally A: adduct and flex the thigh; aids in lateral rotation of the thigh NS: obturator nerve AS: obturator artery and medial femoral circumflex artery

B. Intermediate Layer 1. Adductor Brevis Muscle - the landmark muscle for the two main branches of the obturator nerve and artery, and the perforating branches of the profunda femoris artery O: anterior surface of the inferior pubic ramus I: pectineal line of the femur and (superior ½ of the) medial lip of the linea aspera; shared with pectineus and adductor longus muscles - courses posteroinferolaterally A: adduct and flex the thigh; aids in lateral rotation of the thigh NS: obturator nerve AS: obturator artery and medial femoral circumflex artery

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thigh region, muscles, medial compartment, con’t C. Posterior Layer 1. Adductor Magnus Muscle - the largest adductor muscle O: anterior to posterior orientation of fibers at origin a. inferior aspect of the inferior pubic ramus b. ischial ramus c. inferolateral part of the ischial tuberosity I: superior to inferior orientation of fibers at insertion a. gluteal tuberosity (medial edge) b. medial lip of the linea aspera and the medial supracondylar line c. medial supracondylar line and adductor tubercle - passes from a near sagittal plane origin to a near frontal plane insertion The superior fibers pass transversely from origin to insertion, the central fibers pass obliquely and the inferior fibers pass almost directly inferior. - the superior fibers of the adductor magnus muscle (which originate on the inferior pubic ramus and insert on the gluteal tuberosity) are sometimes referred to as the adductor minimus muscle - the inferior / vertical fibers of the adductor magnus muscle (which originate on the ischial tuberosity, and insert on the medial lip of the linea aspera and the adductor tubercle of the femur) are often termed the hamstring part of the adductor magnus muscle - can palpate the tendon of the hamstring part of the adductor magnus muscle at the medial aspect of the knee region, anterior to gracilis and sartorius muscles, with resisted adduction of the thigh A: adduct the thigh; aid in flexion and extension of the thigh (due to the rotation from origin to insertion) NS: obturator nerve; all except the hamstring part; tibial part of sciatic nerve; hamstring part AS: medial femoral circumflex artery, perforating arteries of the profunda femoris artery, obturator artery, and popliteal artery a. Adductor Hiatus - the opening formed by the vertical fibers / hamstring part of adductor magnus muscle as it passes to its insertion - allows for passage of femoral vessels to the popliteal fossa and popliteal vessels from the popliteal fossa

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thigh region, muscles, medial compartment, con’t 2. Gracilis Muscle - the most medial muscle of the thigh and the medial femoral compartment - crosses the knee joint - described with posterior layer, but not in any one layer O: anterior aspect of the pubic body (inferior part), inferior pubic ramus (medial part) and pubic symphysis (inferior aspect) I: proximal medial shaft of the tibia - forms part of the pes anserinus - courses inferiorly and passes posterior to the medial femoral condyle A: adduct the thigh; flex the leg; aids in medial rotation of the leg (at the knee) NS: obturator nerve AS: medial femoral circumflex, obturator, and profunda femoris arteries D. Pes Anserinus - means goose's foot (webbed with toes) - describes the shape of the insertions of the 3 muscles - the soft tissue structure formed by the 3 tendons that insert at the proximomedial aspect of the tibial shaft 1. Muscles - 3 muscles contribute to the pes anserinus - one from each compartment and this indicates the order of insertion (proximal to distal, and anterior to posterior) a. Semitendinosus muscle - a posterior compartment muscle - the posteroinferior insertion in the pes anserinus b. Sartorius muscle - an anterior compartment muscle - the anterosuperior insertion in the pes anserinus c. Gracilis muscle - a medial compartment muscle - the central insertion in the pes anserinus 2. Bursa Anserina / Anserine Bursa - a complex bursa that separates the 3 tendons that form the pes anserinus from each other and from the bone - it prevents rubbing friction between these structures - may become irritated with repeated internal rotation of the leg at the knee

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