There are three causes of plantar numbness: first, ankle canal syndrome, also known as metatarsal canal syndrome, is ankle canal at the back of the inner ankle, the ankle canal inside the plantar nerve, if the ankle canal has a long lipoma, cyst, or ankle canal stenosis will compress the plantar nerve walking in the ankle canal, thus causing plantar numbness. Second, lumbar disc herniation, lumbar 5 sacral 1 disc herniation after compression of the sacral 1 nerve, sacral 1 nerve innervation is the plantar skin sensation and movement, compression will appear after the plantar numbness. Third, diabetes, diabetes will cause peripheral neuropathy over time, the patient will also appear numbness of the sole of the foot, and will slowly develop upward causing numbness of the dorsum of the foot and the entire lower leg.