Sciatic Nerve Palsy

Key Features

• Misplaced deep intramuscular injections are probably the most common cause

• Trauma to the buttock, hip, or thigh may also be responsible

• The resulting clinical deficit depends on whether the whole nerve or only certain fibers have been affected

• In general, the peroneal (fibular) fibers of the sciatic nerve are more susceptible to damage than those destined for the tibial nerve

• The common peroneal (fibular) nerve itself may be compressed or injured in the region of the head and neck of the fibula (eg, by sitting with crossed legs or wearing high boots)

Clinical Findings

• Weakness of dorsiflexion and eversion of the foot

• Numbness or blunted sensation of the anterolateral aspect of the calf and dorsum of the foot

Diagnosis

• Suggested clinically

• Confirmed by electromyography

• A sciatic nerve lesion may be difficult to distinguish from peroneal neuropathy unless there is electromyographic evidence of involvement of the short head of the biceps femoris muscle

Treatment

• Unless trauma has interrupted the continuity of the nerve, treatment is supportive

• Avoid pressure on the nerve