| Lower extremity
neuropathy |
| Quick synopsis |
 | Meralgia paresthetica: numb anterior lateral
thigh, no motor weakness. |
| Femoral neuropathy: diabetic amyotrophy,
retroperitoneal/pelvic hematoma, tumor. Weak iliopsoas and quadriceps,
numb anterior medial thigh down to medial malleolus. |
| Peroneal neuropathy: trauma at fibular neck. Weak
dorsiflexion, inversion and eversion of ankle. Numb dorsum of foot. |
| Obturator neuropathy: caused by pelvic neoplasm
and surgery, pregnancy. Pain at medial thigh, weak hip adduction. |
|
| Nerve |
History, Exam & Common Etiology |
Femoral - Saphenous
|
| History: leg weakness on attempt to stand |
| Motor: quadriceps weakness |
| Sensory: anterior
medial thigh down to medial malleolus. |
| DTR: decreased Knee reflex |
| Causes:
 | Surgical trauma: intrapelvic, inguinal, hip operations |
| Stretch or traction injury |
| Direct compression in Iliacus compartment |
|
|
| Saphenous |
| History: may go unnoticed or complains of burning pain at medial
lower leg |
| Motor: normal |
| Sensory: medial lower leg loss |
| Causes: Surgical or other injury over the knee or medial lower leg:
arterial surgery, Saphenous vein removal, knee operation |
|
| Obturator |
| History: Leg weakness |
| Motor: hip adduction weakness |
| Sensory: upper medial thigh |
| Isolated involvement uncommon |
| Causes: hip or pelvic fracture, other nerves usually involved. Pelvic
mass |
|
| Iliohypogastric, Ilioinguinal, Genitofemoral |
| History: pain, burning over inguinal & Perineal area |
| Motor: normal |
| Sensory loss:
| Iliohypogastric: suprapubic, upper buttock area |
| Ilioinguinal: inguinal and base of genitalia |
| Genitofemoral: medial & proximal genitalia |
|
| Cause: surgical procedure: especially inguinal herniorrhaphy |
|
| Lateral femoral cutaneous (Meralgia
paresthetica) |
| History: pain, burning over anterolateral thigh |
| Motor: normal |
| Sensory: limited sensory loss over the lateral thigh |
| Common causes: entrapment at lateral inguinal ligament, rarely from
retroperitoneal lesion. |
|
Sciatic
|
| History: complete lesion infrequent, lateral trunk (Peroneal) more
commonly involved |
| Motor: weakness of hamstrings and all muscles below the knee |
| Sensory loss variable: distribution of Peroneal & Tibial nerve |
| Common causes:
| Pelvic, hip or femur fracture |
| Compression injury from prolonged immobility |
| Entrapment by fibrous band, local hematoma, tumor |
|
|
Peroneal
|
| History: Foot drop |
| Motor: weakness of ankle dorsiflexion, eversion,
inversion and toe extension. |
| Sensory loss over anterolateral lower leg, dorsum of foot & toes |
| Causes:
| External compression: pressure, cast |
| External trauma: blunt injury, knee surgery & fracture |
| Traction injury: severe ankle sprain |
|
|
Tibial
|
| History: numbness along the side of foot |
| Motor: weakness in toe flexor, if more proximal portion is involved,
ankle inversion weakness |
| Sensory loss: sole of the foot |
| Rarely seen. |
| Common cause: usually caused by severe ankle injury |
|
Medial & lateral plantar (Tarsal tunnel syndrome)
|
| History: foot pain is more commonly from orthopedic origin.
|
| Motor: may have weakness in toe flexor |
| Sensory loss in toes |
| Common cause: external compression or ankle injury |
|
| Pudendal |
| Fecal & urinary incontinence |
| Sensory loss over perineum |
| Common cause: prolonged labor |
|
| Further reading & review
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