Anatomy 1.4 Upper Limbs - Muscle and Fascia

Anatomy Subject: (1.4) Upper Limbs – Muscle and Fascia Title: Lecturer: Dr. Adelia Quijano, MD Transcribers: Bascara, Battad, Bautista, Bautista, Baybay, Bayona Trans Subject Head: Jacinto, C. (09157536686/[email protected])

I. A. B. C. D. E. F.

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Sem/ A.Y.:

1st/A.Y. 2014-2015

 Thoracic cage = 25  Hyoid = 1 2. Appendicular Skeleton Bones of extremities Superior appendicular skeleton -comprised of the pectoral girdle and bones of the free part of the upper limb Inferior appendicular skeleton – comprised of the pelvic girdle and bones of the free part of the lower limb Composition: o Pectoral girdle = 4 o Pelvic girdle = 2 o Upper limbs = 60 o Lower limbs = 60

OUTLINE

OBJECTIVES

Review the bones and joints of the upper limbs and be able to classify them. Describe the deep fascia of the UL and its subsequent functional compartmentalization of the muscle groups. Describe the fascial spaces: axilla, cubital fossa, and those in the hand, and enumerate their contents. Describe the muscles of the pectoral girdle conceived as anatomical group/functional group and stating their functions. Identify the main muscles of the UL conceived as functional groups in each region with respect to the principal joint movements rather than as individual muscles. Identify the principal attachments of the muscle groups and the joints upon which they act.

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June 23, 2014

Bones and joints of Upper Limb (UL) Fascia of Upper Limb Pectoral Girdle region Arm Forearm Hand II.

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Date:

*sternoclavicular joint– joins upper appendicular bones to the axial skeleton; allows great mobility; fibrous, gliding joint; only point of bony union between trunk and upper limb b.

- 32 bones per side 1.

BONES, MUSCLES, AND FASCIAE OF THE UPPER LIMB A. BONES AND JOINTS OF THE UPPER LIMB

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OVERVIEW OF THE UPPER LIMB

4 Major Segments of the Upper Limb Shoulder includes the pectoral, scapular, and deltoid regions of the upper limb, and the lateral part of the lateral cervical region overlies half of the pectoral girdle *pectoral girdle – formed by scapulae and clavicles, incomplete posteriorly, completed anteriorly by the manubrium of the sternum 2. Arm First segment of the free upper limb Longest segment of the limb Consists of anterior and posterior regions of the arm, centered around the humerus 3. Forearm second longest segment of the limb extends between and connects the elbow and the wrist consists of anterior and posterior regions of the forearm, overlies the radius and ulna 4. Hand composed of the wrist, palm, dorsum of the hand, and digits

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Axial Skeleton Bones along the axis of the body Composed of the  Skull = 22+6  Vertebral column = 26

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Shoulder  Scapula (shoulder blade) triangular flat bone on the posterolateral surface of the thorax overlies the 2nd to 7th ribs Parts: o Acromion process o Coracoid process o Glenoid fossa o Spine 

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Descriptive Regions of the Human Skeleton

BONES OF THE UPPER LIMB

Clavicle (collar bone) Long bone; with absence of medullary cavity Connects upper limb to the trunk First to ossify and last to be formed Most commonly fractured bone in the body

JOINTS:  Glenohumeral joint between shoulder and humerus (ball and socket joint)  Acromioclavicular joint between acromion of the scapula and clavicle (plane joint)  Sternoclavicular joint between manubrium of the sternum and clavicle 2.

Arm (Brachium)  Humerus longest and largest of UL bones

JOINTS:  Radioulnar joint connecting the radius and ulna via an interosseus membrane (syndesmosis joint)  Elbow – between arm and forearm; o Humeroradial joint, Humeroulnar joint (uniaxial, hinge joint; flexion and extension) 3.

Forearm (Antebrachium)  Radius (lateral)  Ulna (medial)

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia JOINT:  4.

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Covers the muscles Made up of dense connective tissue Named according to the area covered (i.e. deltoid fascia, pectoral fascia) Each muscle bundle will be covered by deep fascia and will also extend as covering of tendons. *In the forearm, fascial compartments are separated by an interosseus ligament connecting the radius and ulna Deeper layer of deep fascia Will extend inward to the bone of a particular region to divide that region into compartments (hence it is a boundary for compartmentalization Ex. In arm, the deeper layers of deep fascia will extend inward to attach to the medial and lateral side of the humerus Ex. Arm – divided into anterior and posterior compartment *each compartment will have muscles of similar function and will be innervated by a similar nerve

Proximal radioulnar joint (pivot joint; for pronation/supination)

Wrist (Carpus)  Carpal bones (8) – give flexibility to the wrist 4 Carpal Bones in Proximal Row of Wrist (from lateral to medial) a. Scaphoid b. Lunate c. Triquetrum d. Pisiform 4 Carpal Bones in Distal Row of Wrist (from lateral to medial) a. Trapezium b. Trapezoid c. Capitate d. Hamate

*Mnemonic: Some Lovers Try Positions That They Cannot Handle (Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate) JOINT:  5.

Distal radioulnar joint (pivot joint)

Hand (Manus)  Metacarpals (5)  Phalanges (5 proximal, 4 middle, 5 distal)

***NOTE: DIGITS NOT EQUAL TO FINGERS: 5 digits: 4 fingers and a thumb (thumb has no middle phalanges) JOINTS:  Intercarpal joints (plane or gliding joints)  Carpometacarpal joints (plane joints except the 1st which is a saddle joint)  Intermetacarpal joints (plane joints)  Metacarpophalangeal joints (condylar joints)  Interphalangeal joints (hinge joints)

Figure 2. Cross-sectional view of superficial and deep fasciae (arm) Extensor Retinaculum – transverse band formed by the thickening of the antebrachial fascia posteriorly over the distal ends of the radius and ulna; forms an anterior thickening called the palmar carpal ligament Flexor Retinaculum – located distal and at a deeper level to the palmar carpal ligament; converts the anterior concavity of the carpus into a carpal tunnel, through which the flexor tendons and median nerve pass *The deep fascia of the upper limb continues beyond the extensor and flexor retinacula as the palmar fascia o Palmar aponeurosis thickening at central part of the palmar fascia triangular area at concavity of hand forms four distinct thickenings that radiate to the bases of the fingers and become continuous with the fibrous tendon sheaths of the digits o Thenar fascia – at lateral portion of arm o Hypothenar fascia – medial to thenar fascia, both thenar and hypothenar are THINner than palmar aponeurosis (thenar = thinner) C. PECTORAL GIRDLE REGION a.

ANTERIOR AXIOAPPENDICULAR MUSCLES (UPPER LIMB TO THORAX) 1.

Figure 1. Bones of the Wrist and Hand (posterior view of the right hand) B. FASCIA OF THE UPPER LIMB Fascia – wrapping, packing & insulating materials of deep structures 1.

Superficial Fascia (subcutaneous tissue) Made up of loose connective tissue with fat deposit *In the clinics, superficial fascia = subcutaneous tissue

2.

Deep Fascia

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PECTORALIS MAJOR convergent group of muscles, fan-shaped a. Proximal attachment  Clavicular head: anterior surface of medial half of clavicle  Sternocostal head: anterior surface of sternum, superior six costal cartilages, aponeurosis of external oblique muscle b. Distal attachment  Lateral hip of intertubercular sulcus of humerus c. Main action  Adducts and medially rotates humerus; draws scapula anteriorally and inferiorly

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia PECTORALIS MINOR – smaller; triangular; covers the brachial plexus in the axilla a. Proximal attachment  3rd to 5th ribs near their costal cartilages b. Distal attachment  coracoid process of scapula c. Main action  Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall 3. SUBCLAVIUS – underneath the clavicle a. Proximal attachment  Junction of 1st rib and its costal cartilage b. Distal attachment  Inferior surface of middle third clavicle c. Main action  Anchors and depresses clavicle 4. SERRATUS ANTERIOR – innervated by long thoracic nerve a. Proximal attachment  External surfaces of lateral parts of 1st to 8th ribs (Moore) 2nd to 8th or 9th ribs (Dr. Quijano) b. Distal attachment  Anterior surface of medial border of scapula c. Main action  Protracts scapula and keep it close to the thoracic wall; rotates scapula * WINGING OF SCAPULA - paralysis of serratus anterior/injury to long thoracic nerve

 Extends, adducts, and medially rotates humerus; raises body toward arms during climbing

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DEEP (EXTRINSIC SHOULDER) MUSCLES 1. LEVATOR SCAPULAE a. Proximal attachment  Posterior tubercles of transverse processes of C1 to C4 vertebrae b. Distal attachment  Medial border of scapula superior to root of scapular spine c. Muscle action  Elevates scapula 2. RHOMBOID MINOR AND MAJOR – connect vertebral column to medial border of scapula a. Proximal attachment  Rhomboid minor – Nuchal ligament; spinous processes of C7 and T1 vertebrae  Rhomboid major - spinous processes of T2-T5 vertebrae b. Distal attachment  Rhomboid minor – Smooth triangular area at medial end of scapular spine  Rhomboid major - medial border of scapula from level of spine to inferior angle c. Muscle action  Retract scapula and rotate it to depress glenoid cavity; fix scapula

Figure 3. Anterior Axioappendicular muscles

b.

POSTERIOR AXIOAPPENDICULAR MUSCLES (UPPER LIMB TO VERTEBRAL COLUMN)

SUPERFICIAL (EXTRINSIC SHOULDER) MUSCLES 1.

2.

TRAPEZIUS a. Proximal attachment  Medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7 to T12 vertebrae b. Distal attachment  Lateral third of clavicle; acromion and spine of scapula c. Muscle action  Descending part (lower fibers) elevates scapula  Ascending part (upper fibers) depresses scapula  Middle part (or all parts together) retracts scapula  Both descending and ascending parts together act together to rotate to glenoid cavity superiorly LATISSIMUS DORSI a. Proximal attachment  Spinous processes of inferior 6 thoracic vertebrae, thoracic columbar fascia, iliac crest, and inferior 3 or 4 ribs b. Distal attachment  Floor of intertubercular sulcus of humerus, bicipital groove c. Muscle action

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Figure 4. Posterior Axioappendicular Muscles

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SCAPULOHUMERAL MUSCLES (INTRINSIC SHOULDER MUSCLES) -

Located in the scapula and inserted in the humerus Extrinsic vs. intrinsic  Extrinsic – muscles in a region that act on another region ex. muscles on the forearm that act on the hand  Intrinsic – muscles in the same region that act on that region ex. muscles on the hand that act on the hand 1.

a.

DELTOID  triangular; multipennate; form the rounded contour of the shoulder  base is on proximal end  origin: lateral third of clavicle, acromion process and spine of scapula  has spinal head, clavicular head, acromial head  -will be inserted into deltoid tuberosity of humerus Anterior deltoid –flexion

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia b. c. 2.

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Posterior deltoid – extension Middle portion of deltoid – help in abduction SUPRASPINATUS  Insertion: superior facet of greater tubercle of humerus  Action: Assists deltoid in abduction of arm INFRASPINATUS  Insertion: greater tubercle of humerus, lower than the insertion of supraspinatus  Action: Externally rotates the humerus TERES MINOR  located in the upper part; below insertion of supraspinatus muscle  holds the humeral head in the glenoid cavity of the scapula  laterally rotates the arm  innervated by axillary nerve TERES MAJOR  medial rotator and adductor of the humerus  assists the latissimus dorsi in extending the humerus SUBSCAPULARIS  insert into lesser tubercle of humerus  covers anterior portion of shoulder joint (Infraspinatus, Teres Minor, Supraspinatus covers posterior portion)

**Glenohumeral joint – classified as triaxial joint, ball and socket joint capable of flexion and extension, abduction, lateral rotation, medial rotation  circumduction protected anteriorly, posteriorly and superiorly inferior part: not protected shallow cavity of glenohumeral fossa: frequent dislocation towards the anterior part, common accident at basketball Rotator Cuff Muscles Reinforce the joint capsule, hold the humeral head in the glenoid cavity Remember SITS! (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis)

Figure 5. Scapulohumeral Muscles

d.

FASCIA OF THE PECTORAL REGION 1.

2.

Pectoral fascia  covers the pectoralis major  attached in the middle line, to the front of the sternum; above, to the clavicle; laterally and below it is continuous with the fascia of the shoulder, axilla, and thorax Clavipectoral fascia (clavicle + pectoral)  extends from the clavicle, covers the pectoralis minor muscle and extends to join the axillary fascia

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suspensory ligament of axilla – part of clavipectoral fascia inferior to the pectoralis minor; supports the axillary fascia costacoracoid membrane- part of clavipectoral fascia between the pectoralis minor and subclavius; pierced by the cephalic vein, thoracoacromial artery and lateral pectoral nerve supplying the pectoralis muscle

Axillary fascia  fascia between the pectoralis major and the latissimus dorsi, forming the base of the axilla

AXILLA -

pyramidal space inferior to the glenohumeral joint and superior to the axillary fascia at the junction of the arm and thorax provides a passageway, or “distribution center,” usually protected by the adducted upper limb, for the neurovascular structures that serve the upper limb has an apex, a base, and four walls (three of which are muscular) Contents: brachial plexus, axillary artery & vein, lymph nodes, axillary tail of breast for females (Tail of Spence)

Boundaries/Walls of the Axilla 1. Apex of axilla  the cervico-axillary canal  passageway between the neck and the axilla  bounded by the 1st rib, clavicle, and superior edge of the scapula  arteries, veins, lymphatics, and nerves traverse this  superior opening of the axilla to pass to or from the arm 2.

Base of axilla  formed by the concave skin, subcutaneous tissue, and axillary (deep) fascia extending from the arm to the thoracic wall (approximately the 4th rib level), forming the axillary fossa (armpit)  bounded by the anterior and posterior axillary folds, thoracic wall, and the medial aspect of the arm

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Anterior wall of axilla  has two layers, formed by the pectoralis major and pectoralis minor and the pectoral and clavicopectoral fascia associated with them  anterior axillary fold is the inferiormost part of the anterior wall that may be grasped between the fingers;  it is formed by the pectoralis major, as it bridges from thoracic wall to humerus, and the overlying integument

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Posterior wall of axilla  formed chiefly by the scapula and subscapularis on its anterior surface and inferiorly by the teres major and latissimus dorsi  posterior axillary fold is the inferiormost part of theposterior wall that may be grasped. It extends farther inferiorly than the anterior wall and is formed by latissimus dorsi, teres major, and overlying integument.

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Medial wall of axilla  formed by the thoracic wall (1st–4th ribs and intercostal muscles) and the overlying serratus anterior

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Lateral wall of axilla  narrow bony wall formed by the intertubercular groove in the humerus

Subfascial Spaces A. Quadrangular Space teres minor (above), teres minor (below), triceps brachii, long head (medial), humerus (lateral) Contents: axillary nerve, post humeral circumflex artery B. Triangular Space – teres minor (above), teres major (below), triceps brachii, long head (lateral)

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia –

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contents: circumflex scapular artery from subscapular artery

*Triangle of Auscultation formed by superomedial border of latissimus dorsi, inferolateral border of trapezius, lower part of scapula area where you apply your stethoscope to hear the sounds of the posterior segments of lungs, lesser intervening structures

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D. ARM -

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extends from the shoulder to the elbow two types of movement between the arm and forearm at elbow joint: flexion–extension and pronation–supination

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ANTERIOR: FLEXOR MUSCLES

Nerve Supply: Musculocutaneous nerve Blood supply: Brachial artery 1.

BICEPS BRACHII 2 heads: long head and short head  o Origin: scapula (both heads) o Fuse distally into a single biceps tendon that attaches to radius o Short head appears longer (grossly) Action and effectiveness are affected by the position of the  elbow and forearm: o Flexes the forearm at the elbow joint when forearm is in supination o Primary supinator of the forearm when forearm in is pronation No attachment to humerus o

*Sample activities: right-handed people drive a screw into hard wood, inserting a corkscrew, pulling the cork from a wine bottle *bicipital aponeurosis: triangular membranous band that runs from biceps tendon across the cubital fossa and merges with the antebrachial (deep) fascia 2.

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CORACOBRACHIALIS Elongated muscle in the supero- medial part of the arm  Flex and adduct the arm  Stabilizes the glenohumeral joint  Pierced by the musculocutaneous nerve  Shunt muscle (with deltoid and long head of triceps):  resisting downward dislocation of the head of the humerus (e.g. carrying a heavy suitcase) BRACHIALIS Flattened fusiform muscle that lies posterior (deep) to the  biceps brachii “Workhorse” of the elbow flexors (most powerful flexor of  the forearm) Main flexor of the forearm: flexes the forearm in all  positions (pronation and supination), during both slow and quick movements, and presence or absence of resistance (the only pure flexor)

Crosses the glenohumeral joint Serves as a shunt muscle (with deltoid and coracobrachialis) – resisting inferior displacement of the head of the humerus Medial head  Origin: humerus  Workhorse of forearm extension Lateral head  Origin: humerus  Strongest among the three heads

ANCONEUS Small triangular muscle on the posterolateral aspect of the  elbow Assist triceps in extending forearm  Also stabilizes elbow joint 

* cubital fossa- shallow triangular depression on the anterior surface of the elbow. Boundaries are:  Superiorly: imaginary line connecting the medial and lateral epicondyles  Medially: pronator teres o Laterally: brachioradialis o Floor: brachialis and supinator o Roof: brachial and antebrachial fascia *contents of the cubital fossa: Radial nerve Biceps brachii tendon Brachial arteries and veins Median nerve [RBBM – Ron Beats Bad Men] E. FOREARM -

Extends from elbow to wrist Radius and ulna joined by interosseus membrane (permits pronation and supination; provides proximal attachment for some deep forearm muscles)

a. ANTERIOR: FLEXOR/PRONATOR MUSCLES Nerve supply – median nerve; 1 ½ by ulnar nerve -

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Anterior surface of wrist tendons held in place by palmar carpal ligament + flexor retinaculum (thickenings of antebrachial fascia) Common flexor tendon/origin: medial epicondyle of humerus Functionally, includes brachioradialis

Superficial Layer Crosses elbow joint Wrist joint action (except for pronator teres – acts on radioulnar joint) Muscles involved: 1. PRONATOR TERES – pronates and flexes 2. FLEXOR CARPI RADIALIS (FCR) – flexes  + extensor carpi radialis longus and brevis = abduct  Flex + abduct = Hand moves anterolaterally 3. PALMARIS LONGUS  flexes hand at wrist and tenses palmar aponeurosis 4. FLEXOR CARPI ULNARIS (FCU) – flexes  + Extensor carpi ulnaris = adduct  Most medial

*Sample activities: pick up and put down a teacup b.

POSTERIOR: EXTENSOR MUSCLES

Nerve Supply: Radial nerve Blood supply: Brachial artery 1. TRICEPS BRACHII Large fusiform muscle in the posterior compartment of the  arm Main extensor of the forearm  3 heads (long, lateral and medial heads)  Heads of triceps brachii: a. Long head  Origin: scapula

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia *Note: fingers can be independently flexed at the proximal but NOT at distal interphalangeal joint 2.

FLEXOR POLLICIS LONGUS (FLP)  long (longus) flexor of thumb (pollicis)  Flexes distal phalanx of the thumb ( interphalangeal joint) and proximal phalanx and 1st metacarpal (metacarpophalangeal and carpometacarpal joints)  Assist in flexion of wrist joint  Lateral to FDP

3.

PRONATOR QUADRATUS prime pronator of forearm  Deepest muscle  Attaches to ulna at one end and radius at the other end

Figure 6. Flexors of the forearm (Superficial layer)

Figure 9. Flexors of the forearm (deep layer) Figure 7. Superficial flexor muscles of the forearm (for easy recall) Intermediate Layer Crosses elbow Muscle involved: 1. FLEXOR DIGITORUM SUPERFICIALIS (FDS) - flexes middle phalanges at proximal interphalangeal joints and proximal phalanges at metacarpophalangeal joints and wrist joint -Gives rise to four tendons which pass deep to flexor retinaculum

Figure 8. Flexors of the forearm (Intermediate layer – Flexor digitorum superficialis) Deep layer 1. FLEXOR DIGITORUM PROFUNDUS* (FDP)  flexes distal interphalangeal joints  flexes distal phalanges after FDS flexed middle phalanges  Index finger – independent contraction  “Clothes” anterior part of ulna  Profundus/profound – deep

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*Cubital fossa – bounded laterally by extensor-supinator group of muscles attached to lateral epicondyle Radial artery traverses up to the wrist; separating flexorpronator and extensor – supinator compartments b.

POSTERIOR: EXTENSOR/SUPINATOR MUSCLES Held by extensor retinaculum (prevents bowstringing of tendon)

Nerve supply: Radial nerve Superficial layer Originates in lateral epicondyle 1. BRACHIORADIALIS – flexes forearm to the elbow  Incapable of acting at the wrist since brachioradialis and supinator do not cross  Anterior of the arm  Active during quick movements or presence of resistance during forearm flexion 2. EXTENSOR CARPI RADIALIS LONGUS – indispensable when clenching fist  Acts as synergist together with ECRB 3. EXTENSOR CARPI RADIALIS BREVIS(short) – shorter than ECRL  ECRL + ECRB = abduct hand as they extend  ECRL + ECRB + FCR = pure abduction  ECRL + ECRB (more involved than longus) + ECU = extend hand  Synergistic action of ECRL (more involved) and ECRB with ECU = clench fist 4. EXTENSOR DIGITORUM (COMMUNIS) – principal extensor of medial 4 digits  Extends proximal phalanges; middle and distal phalanges as well  Helps extend hand at wrist joint 5. EXTENSOR DIGITI MINIMI – extends little finger 6. EXTENSOR CARPI ULNARIS – extends hand  ECU + ECRB + ERCL = extends

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia  

ECU + FCU = Adducts Indispensable when clenching fist

Deep layer 1. SUPINATOR – prime mover for slow unopposed supination esp when extended forearms 2. ABDUCTOR POLLICIS LONGUS – Abducts thumb  + APB = abducts thumb  + EP muscles = Extends thumb 3. EXTENSOR POLLICIS BREVIS – extends proximal phalanx of thumb; helps extend 1st metacarpal + extend and abduct hand 4. EXTENSOR POLLICIS LONGUS – extends distal phalanx of thumb + adducts the extended thumb + rotates laterally *Anatomical Snuffbox – hollow, fascial space bet. Tendons of EPL & EPB – Seen on radial aspect of wrist – Contains radial artery – Floor: scaphoid and trapezium 5. EXTENSOR INDICIS – confers independence of index finger + extend index finger (w/ E Digitorum) + extends hand

Figure 11. Palmar fascia Dorsal Fascia – posterior aspect of the hand  Digital fibrous flexor sheaths – covers the flexor digitorium tendon b.

FASCIAL SPACES AND COMPARTMENTS OF THE PALM

Compartments 1. THENAR COMPARTMENT space between the attachment of the palmar aponeurosis to the 3rd metacarpal bone contains thenar muscle lateral to lateral fibrous septum Figure 10 Posterior muscles of the forearm

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F. HAND a.

DEEP FASCIA OF THE HAND

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Retinacula 1. FLEXOR RETINACULUM - forms the carpal tunnel (palmar side of the wrist that connects the forearm to the middle compartment of the deep plane of the palm) where the ff. pass through:  flexor digitorum superficialis  flexor digitorum profundis  flexor pollicis lingus **Carpal Tunnel Syndrome - numbness over lateral 3.5 digits with weakness and atrophy of thenar muscles due to pressure on the median nerve 2.

HYPOTHENAR COMPARTMENT space between the attachment of the palmar aponeurosis to the 5th metacarpal bone medial to medial fibrous septum -

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CENTRAL COMPARTMENT between the thenar and hypothenar compartments space occupied by:  flexor tendons  lumbricals  superficial palmar arterial arch  digital vessels  nerves

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ADDUCTOR COMPARTMENT Deepest muscular plane of the palm

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INTEROSSEUS COMPARTMENT Found between metacarpals

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EXTENSOR RETINACULUM – holds the extensor tendons in place

Palmar Fascia – anterior aspect of the hand 1. PALMAR APONEUROSIS between the two eminences (thenar and hypothenar) overlies long flexor tendons forms four longitudinal digital bonds from apex to distal attached to proximal phalanges and continuous with fibrous digital sheaths 2. THENAR – base of the thumb 3. HYPOTHENAR – proximal to the base of the 5th finger

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia

Figure 12. Compartments, spaces, and fascia of the palm Figure 13. Synovial flexor sheaths Palmar Spaces 1. Mid-palmar space – extension and covering to the flexor group of tendons 2. Thenar space – extension and covering to the thumb

Figure 12. Palmar spaces Synovial Flexor Sheaths 1. Ulnar bursa – protects the flexor digitorium superficialis and profundus 2. Radial bursa - protects the flexor pollicis longus

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INTRINSIC MUSCLES OF THE HAND

Thenar Compartment 1. ABDUCTOR POLLICIS BREVIS abducts the thumB assists the opponenspollicis during early stages of opposition through rotating its proximal phalynx 2. FLEXOR POLLICIS BREVIS short flexor of the thumb has two heads (bellies): the larger superficial head is innervated by the median nerve while the smaller deep head is innervated by the ulnar nerve 3. OPPONENS POLLICIS quadrangular muscle, opposes the thumb flexes and rotates the first metacarpal medially at the carpometacarpal joint during opposition 4. ADDUCTOR POLLICIS With two heads of origin (oblique and transverse) which are separated by the radial artery as it enters the palm to form the deep palmar arch Adducts the thumb Hypothenar Compartment (act on little finger) 1.

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ABDUCTOR DIGITI MINIMI most superficial layeR abducts the fifth finger FLEXOR DIGITI MINIMI BREVIS originates in the pisiform flexes the proximal phalynx of the fifth finger at the metacarpophalangeal joint OPPONENS DIGITI MINIMI draws the fifth metacarpal anteriorly and rotates it laterally PALMARIS BREVIS not in the hypothenar compartment BUT it wrinkles the skin of the hypothenar eminence and deepens the hollow of the palm, to aid the palmar grip -

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia

Figure 16. Palmar Interosseus muscles

Figure 14. Intrinsic Muscles of the Hand (anterior view) Middle Compartments 1. LUMBRICAL MUSCLES flex the fingers at the metacarpophalangeal joints and extend the interphalangeal joint nerve supply: median nerve (1st and 2nd) and ulnar (3rd and 4th) 2.

MUSCLES IN INTEROSSEI **(Mnemonic: DABPAD)  Dorsal Interosseous Muscles (4) Dorsal Abuction – nerve supply: ulnar nerve

IV. 1.

It is a large fusiform muscle in the posterior compartment of the arm. a. triceps brachii b. anconeus c. biceps brachii d. coracobrachialis

2.

A girl picks up and puts down her morning cup of tea. Which arm muscle is primarily used? a. triceps brachii b. brachialis c. biceps brachii d. anconeus

3.

Damage to the coracobrachialis muscle and its nerve supply would weaken which motion of the arm and forearm? a. Extension b. Rotation c. Flexion d. Supination e. Abduction

4.

Nerve that supplies posterior extensor/supinator muscles a. radial nerve b. ulnar nerve c. axillary nerve d. median nerve

Figure 15. Dorsal interosseums muscles 

GUIDE QUESTIONS

Palmar Interosseous Muscles (3) Palmar Adductionnerve supply: ulnar nerve

5. What muscle will be affected if there is injury to the long thoracic nerve? a. latissimus dorsi b. serratus anterior c. pectoralis minor d. coracobrachialis 6.

2018-A

Transverse thickening of deep fascia anterior to the wrist area a. flexor retinaculum b. flexor pollicis brevis c. extensor retinaculum

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ANATOMY 1.4 Upper Limbs – Muscle and Fascia d.

anatomical snuffbox

Answers: ABCABA V. REFERENCES 1. Moore, K. et al. (2010). Clinically oriented anatomy. 8th ed. Lippincott Williams & Wilkins: Baltimore, MD

2018-A

2. Netter, F. (2014). Atlas of Human Anatomy. 6th ed. Saunders Elsevier: Philadelphia, USA. 3. Quijano, A. (2014). Lecture presentation. Upper Limbs – Muscle and Fascia. University of the East Ramon Magsaysay Memorial Medical Center, Quezon City.

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