Several major nerves serve the human foot. On the top surface of the foot are the dorsal digital nerves and their branches: the deep peroneal nerve, the medial dorsal cutaneous nerve, the intermediate dorsal cutaneous nerve, and the sural nerve. Also on the front surface is the saphenous nerve, which is not included among the dorsal digital nerves because it does not penetrate any of the toes. On the sole, the nerves of the foot are the medial and lateral plantar nerves, which arise from the tibial nerve in the heel.
The dorsal digital nerves are those nerves of the foot that cross the top surface and insert in the digits, or toes. Also known as the deep fibular nerve, the deep peroneal nerve branches off from the common fibular nerve at the top of the back of the lower leg on the side of the fibula bone. Curving toward the big-toe side of the foot, it crosses the ankle and splits into medial and lateral branches. These nerves serve the muscles that extend or straighten the toes.
Another of the nerves of the foot situated on the side of the big toe is the medial dorsal cutaneous nerve, with cutaneous referring to the fact that this nerve innervates the skin. Also splitting into two branches after crossing the ankle, this dorsal digital nerve innervates the first two toes and the medial side of the third toe. Entering the foot alongside the medial dorsal is another dorsal digital nerve, the intermediate dorsal cutaneous nerve, which supplies most of the lateral or outer half of the forefoot. Specifically, it serves the lateral side of the third toe, both sides of the fourth toe, and the medial side of the fifth or pinky toe.
The last of the dorsal digital nerves of the foot is the sural nerve. This nerve enters the foot along the outside of the ankle and runs to the fifth toe, supplying only the lateral side of the toe. On the opposite side of the foot is a nerve that is not counted among the dorsal digital nerves, the saphenous nerve. This nerve penetrates the medial side of the foot, ending just beneath the big toe, and it is the nerve that innervates the skin on the inside edge of the foot.
Fewer nerves of the foot are located on the bottom surface than on the top of the foot, even though this is the surface of the foot that comes in contact with the ground. Those found on the underside of the foot are the medial and lateral plantar nerves, which arise from the posterior portion of the large tibial nerve of the leg. The medial plantar nerve is found on the big-toe side of the foot. It supplies the muscles that flex or curl the toes as well as those that abduct and adduct, or fan out and bring together, the toes. It also innervates the skin on this half of the sole of the foot, including the plantar surfaces of the first three and a half toes. The lateral plantar nerve supplies a few minor muscles along the outer portion of the sole of the foot as well as the skin found here, including the undersides of the pinky toe and the lateral half of the fourth toe.
