What causes foot drop?

According to Mayo Clinic, foot drop is caused by weakness in the muscles that lift the front portion of the foot. This muscle weakness can be caused by a muscle or nerve disorder, a brain or spinal cord disorder, or a nerve injury.

Mayo Clinic states that the most common cause of foot drop is a nerve injury. If one of the nerves that controls the muscles in the foot is compressed or damaged then foot drop can occur. This can also happen with a nerve near the knee or the lower spine. Long-term nerve damage from diseases such as diabetes can also cause nerve injury that leads to foot drop, states the Mayo Clinic.