Summary of Nerves of Lower Limb

NERVE

Sciatic Nerve

ROOT VALUE

L4, 5, S1, 2, 3

ORIGIN

Inside the pelvis

COURSE & RELATION

Leaves the pelvis through greater sciatic foramen below piriformis Descend in gluteal region under cover of gluteus maximus Lies on: o back of ischium separated by nerve to quadratus femoris o tendon of obturator internus + 2 gemilli muscle o quadratus femoris which separate from hip joint At the back of the thigh, the nerve passes undercover of the long head of biceps femoris Lies on the posterior aspect of adductor magnus

Tibial Nerve (Medial Popliteal Nerve) Ventral divisions of L4, 5, S1, 2, 3 Larger part of 2 terminal branches of sciatic nerve At the junction of upper ⅔ & lower ⅓ of the back of the thigh Enters popliteal fossa at its upper angle & leaves at its lower angle Ends at lower border of popliteus muscle – enters the back of the leg – become posterior tibial nerve At first, it lateral to popliteal vessel Then crosses superficially to become medial to vessels

Common Peroneal Nerve (Lateral Popliteal Nerve) Dorsal division of L4, 5, S1, 2 Smaller part of 2 terminal branches At lower ⅓ of the back of thigh

Enters popliteal fossa at its upper angle Passes along medial border of biceps femoris to leave the fossa at its lateral angle Passes around neck of fibula deep to peroneus longus

TERMINATION

At upper angle of popliteal fossa By dividing into tibial & common peroneal nerve

Articular branches → hip joint

Cutaneous branch Sural nerve

Muscular branches o Tibial part  ischial head of adductor magnus  semitendinosus

Muscular branches Double nerves to gastrocnemius Nerve to plantaris Nerve to superficial surface of soleus Nerve to popliteus

 semimembranosus

BRANCHES

Lower border of popliteus muscle By becoming posterior tibial nerve

 long head of biceps o Common peroneal part  short head of biceps Terminal branches o Tibial nerve o Common peroneal nerve

Genicular (articular branch) Superior and inferior medial genicular nerves Middle genicular nerve

Lateral side of neck of fibula by dividing into: deep peroneal (anterior tibial) nerve superficial peroneal (musculocutaneous) nerve Cutaneous branches Sural communicating nerve Lateral cutaneous nerve of calf Articular branches Superior lateral genicular nerve Inferior lateral genicular nerve Recurrent genicular nerve Terminal branches (see termination)

NERVE INJURY

Causes: Sites & causes: wounds Sites & causes: in the popliteal fossa Post dislocation of Wounds in the hip joint popliteal fossa Wrong intramuscular Effect: Fracture of the neck Paralysis to muscle inject of fibula of back of the leg & Penetrating wounds Tight plaster cast sole of foot Severe adductor Loss of sensation at Effect: trauma to the leg the back of the leg Paralysis of & sole of the foot hamstring muscles, Effect: ischial part of Paralysis of the Deformity: (Talipus adductor magnus & muscles of the Calceneovalgus) all muscles of leg & anterior Dorsiflexion foot (flail foot) compartment of the Eversion Complete sensory leg (extensors) loss below knee Clawing of toes Paralysis of the except area along muscles of the medial malleolus & lateral compartment med side of foot of the leg (evertors) which is supplied by Loss of sensation saphenous nerve from anterolateral aspect of the leg to Deformity: foot drop the dorsum of the due to effect of gravity foot (except the medial and lateral borders) Deformity: (Talipus equinovarus) Foot drop (paralysis of extensors of foot) Inversion (paralysis evertors of the foot)

Deep Peroneal Nerve (Anterior Tibial Nerve) As one of 2 terminal branches of common peroneal nerve ORIGIN At the lateral acpext of the neck of fibula deep to peroneus longus Pierces anterior intermuscular septum to enter anterior COURSE compartment of leg & Descend downward in front of RELATION ankle joint midway between 2 malleoli Dorsum of foot by dividing into TERMINATION lateral & medial branches Muscular branches Tibialis anterior Extensor hallucis longus Extensor digitorum longus Peroneus tertius Extensor digitorum brevis NERVE

Cutaneous branches by medial terminal nerve Cleft between 1st & 2nd toes BRANCHES

Articular branch from main trunk Ankle joint Articular branches from terminal branches Tarsal joint Tarsometatarsal joint Terminal branches Lateral terminal branch Medial terminal branch

Superficial Peroneal Nerve (Musculocutaneous Nerve) As one of 2 terminal branches of common peroneal nerve At the lateral side of the neck of fibula Descends in substance peroneus longus Then passes to reach peroneus brevis Pierces deep fascia at distal ⅓ of leg Dividing into lateral & medial branches Muscular branches Peroneus longus Peroneus brevis Cutaneous branches from main trunk Skin of lower ⅔ of the anterolateral aspect of the leg Cutaneous branches from medial & lateral terminal branches Dorsum of foot & toes except: Lateral border (sural nerve) Medial border (saphenous nerve) Cleft between 1st & 2nd toes (anterior tibial nerve) Cutaneous branches from medial terminal Medial side of bog toe Adjacent sides of 2nd & 3rd toes

NERVE ROOT VALUE

ORIGIN

COURSE & RELATION

TERMINATION

Posterior Tibial Nerve Ventral divisions of L4, 5, S1, 2, 3 Lower border of popliteus As continuation of tibial nerve Descend deep to soleus muscle between tibia & fibula Passes in the posterior compartment of the leg between superficial & deep muscles of calf Passes deep to flexor retinaculum, behind & below medial malleolus between flexor digitorum longus & flexor hallucis longus to end as medial & lateral plantar nerves Ends deep to the flexor retinaculum behind medial malleolus By dividing into lateral plantar nerve & medial plantar nerve

Medial Plantar Nerve

Deep to flexor retinaculum As the larger of 2 terminal branches of posterior tibial nerve Runs forward in the sole of the foot lateral to medial plantar artery between abductor hallucis & flexor digitorum brevis muscles

Lateral Plantar Nerve

Deep to flexor retinaculum As the smaller of 2 terminal branches of posterior tibial nerve Pass forward & laterally on the medial side of lateral plantar artery between 1st & 2nd layers of sole Till it reaches base of 5th metatarsal bone

BRANCHES

Muscular branches Muscular branches Flexor digitorum Abductor hallucis longus Flexor hallucis brevis Flexor hallucis longus Flexor digitorum Tibialis posterior brevis Deep surface of 1st lumbrical muscle soleus Cutaneous branches Cuteneous branch Skin of medial ⅔ of Medial calcanean sole nerve Digital branches to skin of plantar Articular branch surface of medial 3 Ankle joint ½ toes Terminal branches Medial plantar nerve Lateral plantar nerve

Muscular branches from main trunk Flexor digitorum accessories Abductor digiti minimi Muscular branches from terminal branches Adductor hallucis Flexor digiti minimi brevis Lateral 3 lumbrical muscles 7 interossei muscles

Articular branches Cutaneous branches Intertarsal joint Lateral ⅓ of sole tarsometatarsal joint Lateral 1 ½ of toes Articular branches Intertarsal joint Tarsometatarsal joint