Sciatic nerve palsy is usually related to trauma. Hip fracture is the most common cause frequently associated with fracture of the posterior acetabulum, and posterior displacement of the femoral head.

Intramuscular injections in the gluteal region can cause sciatic damage, especially in newborns and debilitated patients, probably more because of chemical irritation than mechanical needling.

Diagnosis of sciatic nerve palsy is made on the basis of history, neurogic test, nerve conduction studies and electromyography. Electrophysiologic studies are simple, relatively quick, and accurate method for the diagnosis of peripheral nerve lesion. And so, electrophysiologic studies are a very useful to the measure of severity, detection of location, and differential diagnosis of sciatic nerve palsy.

A retrospective analysis of 24 consecutive cases of sciatic nerve palsy seen from June of 1986 to December of 1987 in the department of Rehabilitation Medicine at Catholic University Medical College was carried out. They were confirmed to have sciatic nerve palsy by clinical finding and electrodiagnostic studies.

The results of this were as follows.

1) Of a total 24 cases, 22 were males and 2 were females. The most them were in their twenties and thirties (52.4%).

2) The major causes for lesions were fracture of pelvis and femur (45.8%).

3) The most frequent site of the lesions was the peroneal division of sciatic nerve (50.0%). The type of injuries was an incomplete injury in 20 cases, and a complete injury in 4 cases.

4) The symptoms observed were a motor weakness (87.4%), sensory change (83.3%) and muscle atrophy (45.8%).

5) 20 cases showed abnormalities in conduction study and needle EMG study, and only 4 cases showed abnormalities in the needle EMG study.

6) The 4 cases with out sensory change showed abnormalities in sensory nerve conduction study.

7) On sensory conduction studies of sural and superficial peroneal nerves, the two cases were 70.8% and 87.5% respectively, showing abnormal conductions.

8) On motor conduction studies of peroneal and tibial nerves, the two cases were 70.8% and 41.7% respectively, showing abnormal conductions.

9) On needle EMG study, all cases showed spontaneous activity in sciatic nerve innervated muscles.