Foot drop is the damage to the common peroneal nerve that causes the foot to be unable to lift dorsally, there are several causes of foot drop: first, tumors around the common peroneal nerve, tumors around the common peroneal nerve can compress the common peroneal nerve and cause foot drop. Second, tumors of the common peroneal nerve, such as neurofibroma, can cause damage to the common peroneal nerve, which can also lead to foot drop. Third, the common peroneal nerve cut injury, such as knife injury damage to the common peroneal nerve, will also appear the common peroneal nerve dysfunction, foot ptosis. Fourth, lumbar disc protrusion, lumbar disc protrusion, if the compression of the nerve for a longer period of time, will also appear the symptoms of foot ptosis. Fifth, whether it is intravertebral tumor, if the intravertebral tumor compresses the nerve, it will also lead to the symptoms of foot drop.