Nerve · Lower leg

Medial sural cutaneous nerve

Nervus cutaneus surae medialis

The tibial nerve's contribution to the skin of the calf, and the parent stem of the sural nerve. It leaves the tibial nerve in the hollow behind the knee, then descends in the groove between the two bellies of gastrocnemius — one of the few nerves that runs inside a muscle's midline rather than along its border — and pierces the deep fascia around the middle of the calf. From that point it is usually joined by a branch from the common fibular side and continues under a new name, the sural nerve. It is best thought of as the upper half of that nerve rather than as a separate structure.