Medial sural cutaneous nerve

At a glance

English

Medial sural cutaneous nerve

Latin (TA2)

Nervus cutaneus medialis surae

System

Nerve

Region

Lower limb

Side

Paired, left and right

About the medial sural cutaneous nerve

This branch carries only sensory fibres and comes from the tibial nerve, the larger of the two terminal divisions of the sciatic nerve. It leaves the back of the tibial nerve in the middle of the popliteal fossa, between the heads of gastrocnemius, and is the main contributor to the sural nerve of the calf.

From its origin it runs down in the shallow groove between the medial and lateral heads of gastrocnemius, lying beneath the deep fascia of the leg and accompanied by the small saphenous vein, which also runs in this groove. Roughly halfway down the calf it passes through the deep fascia to lie under the skin. There, or a little lower, it receives the sural communicating branch of the common fibular nerve, and the united trunk continues down as the sural nerve towards the lateral malleolus.

Before the junction it supplies skin over the back of the calf. After it joins the fibular branch its fibres pass on to the posterolateral part of the lower leg, the lateral heel and ankle, and the lateral border of the foot. The level of the junction is variable: it may be high in the calf, low near the ankle, or absent, so that the medial sural nerve continues alone as the sural nerve. The two sides of the same person may differ.

The nerve is a landmark in the popliteal fossa, where it lies superficial to the popliteal vessels close to the small saphenous vein's termination. It can be injured when that vein is ligated or stripped for varicose veins, causing numbness or tingling along the back of the calf and outer foot. When surgeons take the sural nerve for a graft, they often trace it up to this branch to gain extra length. Because it is part of the sural nerve's input, it is included in sural nerve conduction studies for peripheral neuropathy.

Course and supply

Arises from

The back of the tibial nerve, midway down the popliteal fossa.

Ends in

Pierces the deep fascia in mid-calf and is joined by the common fibular nerve's sural communicating branch, the two making the sural nerve.

Supplies

Sensory to the skin of the back of the calf and, through the sural nerve, the lateral ankle and foot.