Causes and Risks Sciatic nerve dysfunction is a form of peripheral neuropathy . It occurs when there is damage to the sciatic nerve, located in the back of the leg which supplies the muscles of the back of the knee and lower leg and sensation to the back of the thigh, part of the lower leg, and the sole of the foot. Dysfunction of a single nerve group, such as the sciatic nerve, is classed as mononeuropathy .
Entrapment involves pressure on the nerve where it passes through a narrow structure.
The damage slows or prevents conduction of impulses through the nerve. The sciatic nerve is commonly injured by fractures of the pelvis or by gunshot wounds or other trauma to the buttocks or thigh. The nerve may be injured during intramuscular injections into the buttocks. Prolonged sitting or lying with pressure on the buttocks may also injure it. Systemic diseases such as diabetes mellitus can typically damage many different nerves, includingthe sciatic nerve.