COMMON PERONEAL NERVE1

Anatomy Formed by: Axons from L4, L5, S1 & S2 roots Course of axons

o Through popliteal fossa: Separates from sciatic nerve in upper fossa

o Behind head & along fibula: Covered only by skin & subcutaneous tissue

o Behind peroneus longus muscle (fibular tunnel): In anterior compartment of leg

o Emerge from fibular tunnel: Nerve divides into superficial & deep branches

o Deep peroneal nerve passes through: Anterior tarsal tunnel Divides into lateral and medial terminal branches Lateral terminal branch: Supplies Extensor digitorum

brevis & Extensor hallucis brevis Medial terminal branch

o Supplies adjacent sides of great & 2nd toes (92%)o Absent in 8%: Muslces supplied by Superficial

peroneal nerve Branches

o Common peroneal in popliteal fossa: Sensoryo Superficial peroneal

Motoro Peroneus breviso Peroneus longuso Accessory deep peroneal branch: Innervates

Extensor digitorum brevis Cutaneous sensory

o Lower leg: Anterolateralo Foot: Dorsum, except between 1st 2 toeso Medial & Intermediate dorsal cutaneous nerves of

footo Deep peroneal

Motor branches in lego Tibialis anterioro Extensor hallucis & Extensor digitorum longuso Peroneus tertius

Lateral terminal branch in footo Extensor digitorum brevis

May also be innervated by accessory deep peroneal from superficial peroneal (28%)

o Cutaneous: Skin between 1st & 2nd toes

Clinical syndrome Weakness

o Foot: Dorsiflexion & Eversion of footo Toes: Extensiono Gait: Steppage

Sensory losso Lower leg: Anterolateralo Foot & Toes: Dorsum

Tendon reflexes: Normal Pain & Tinel's sign: Over lateral fibular neck

Differential diagnosis L5 root: EHL may be weaker than Anterior tibial Lumbosacral trunk or plexus Sciatic nerve: Lateral trunk

Causes External compression

o Fibular head lesion Etiologies

o Especially with weight losso Altered consciousness: Coma, Anesthesia, Sleep

& Bed resto Crossed legso Leg braces

Partial lesion: More involvement of deep peroneal than superficial peroneal axons

o Distal: Superficial peroneal nerve (Sensory branches) Branches: Medial & Intermediate Dorsal cutaneous

branches Clinical

o Sensory loss: Medial dorsal foot up to ankle Trauma: Blunt; Traction; Fractures

o Ankle: Acute plantar flexion & inversion Entrapment

o Squatting (Gardners & Farmers): Lesion locations Compression between biceps tendon & lateral head of

gastrocnemius + Head of the fibula Fibular tunnel Anterior tarsal tunnel: Deep peroneal nerve

o Masses Ganglia: From the superior tibiofibular joint Baker's cyst

Schwannoma & Neurofibromas: Especially in popliteal fossa

o Fibular tunnel: Crescentic band at origin of peroneus longus Mononeuropathy in systemic disorder

o HNPP o Vasculitis o Diabetes mellitus o Leprosy

Deep peronealo Anterior compartment syndrome

Raised pressure in fascial compartment Causes: Excessive exercise, Soft tissue trauma,

fractures, haemorrhage, occlusion of anterior tibial artery

Clinical associations: Leg swellingo Compression: Ganglia, Osteochondroma, Aneurysmo At ankle

Trauma & External compression Weak: Extensor digitorum brevis

Superficial peronealo Peroneal compartment syndromeo Local traumao Compression of sensory branch when traversing deep fascia of

lower leg

External link: Wheeless

POSTERIOR TIBIAL NERVE

Anatomy Formed by: Axons from L4, L5, S1 & S2 roots Anatomy

o Anterior component: Muscles of posterior thigh (except short head of biceps)

o Popliteal space: Branches to popliteus; Gastrocnemius; Soleus; Plantaris

o Posterior compartment of leg: Tibialis posterior, Flexor hallucis longus; Flexor digitorum brevis

o Behind medial malleolus to plantar side of footo Tarsal Tunnel

Anatomy: Behind mdial malleolus; Covered by flexor retinaculum

Contents: Tibial nerve; Tibial artery; Tendons FHL, FDL, Tibialis posterior

o Distal tibial nerve branches Medial & Lateral Calcaneal: Sensory supply to heel of

sole Medial Plantar nerve

o Sensory: Medial 3 1/2 toeso Motor: Abductor hallucis brevis; Flexor hallucis

brevis; Flexor digitorum brevis; Lumbricales Lateral Plantar nerve

o Sensory: Little toe & Lateral 4th toeo Motor: Abductor digiti quinti brevis; FDB;

Quadratus plantae

Tarsal Tunnel Syndrome Anatomy: Entrapment of tibial nerve in tarsal tunnel Clinical

o Pain Peri-malleolar Ankle & Sole: Burning; Worse with weight bearing & at

night Tinel sign: Over tarsal tunnel Ankle dorsiflexion

o Paresthesias & Sensory loss Sole of foot

o Intrinsic foot muscles: Weak & Wastedo Tendon reflexes: Normal

Causeso Mass in tunnel: Lipoma, Ganglia, Neoplasmso Exostosis within the tarsal tunnelo Accessory flexor digitorum longus muscle: 4% to 8% of legso Hindfoot valgus deformityo Athletics: Heavy stress on ankle joint; Sprinting, Jumping

Differential diagnosiso Sensory polyneuropathyo Orthopedic: Fasciitis; Tendonitis

External link: Wheeless

LATERAL FEMORAL CUTANEOUS NERVE

Anatomy

o Direct extensions from L2 & L3 rootso Passes under inguinal ligamento Sensory distribution: Anterior lateral thigho May anatomose with: Superior perforator & Median perforator

nerves More anterior thigh sensory field

Lateral Femoral Cutaneous Neuropathy: Meralgia parestheticao Entrapment site: Inguinal ligamento General

Male ? > Female Age: Mean 51 years; Range 15 to 81 years; Most

frequent 4th & 5th deacde Symptom duration: 0.5 months to 20 years; Mean 3

yearso Clinical

Pain: Burning, tingling, Aching Sensory loss

o Sharply defined regiono Anterior or Lateral thigh or Botho Never involves: Patella; Knee; Lateral iliac crest

Tendon reflexers: Normal Strength: Normal Bilateral: 10%; Usually asymmetric

o Predisposing factors Obesity Tight pants or belt Diabetes: Occasional; Not clearly associated Pregnancy Abdominal pressure: Increased Surgery: Spine; Pelvic osotomy

o NCV Side to side variation of orthodromic amplitude >2.3

fold SNAP amplitude < 3 μV

o Management Conservative in most cases Weight loss Eliminate tight fitting clothes

FEMORAL NERVE

Anatomy

o Roots: L2, L3, L4o Derived from: Lumbar plexuso Branches above inguinal ligament: Psoas; Iliacuso Below inguinal ligament: Divides into anterior & posterior

divisions Anterior: Medial & intermediate cutaneous nerves of

thigh; Sartorius & Pectineus muscle Posterior: Quadriceps femoris (Vasti & Rectus femoris);

Saphenous nerve Neuropathy

o General Weakness: Hip flexion; Knee extension Sensory loss: Anterior & Medial thigh; Medial leg to

medial malleolus Tendon reflex: Knee reduced or absent

o Lesions Compression: Surgical positioning (Lithotomy) &

retraction Ischemia: Renal transplantation; Diabetes Retroperitoneal hemorrhage: Lumbar plexopathy with

prominent femoral involvement Saphenous nerve : Axonal loss with increasing age