Foot drop is caused by damage to the peroneal nerve, which controls the muscles that raise the foot toward the knee.

Illnesses that cause peroneal nerve damage and foot drop include:

• Alcoholic neuropathy
• Diabetic neuropathy
• Peripheral neuropathy

Injuries that cause peroneal nerve damage and foot drop include:

• Leg contusion:
• With neurapraxia involving the peroneal nerve
• Herniated disk in the lower back
• Knee fracture:
• That damages the peroneal nerve
• Leg fracture:
• That damages the peroneal nerve
• Pressure against the peroneal nerve:
• Tight cast
• Leg crossing