Now we’ll look at the nerves of this region, the tibial nerve, and the common peroneal nerve. We saw them last at the knee, the tibial nerve disappearing, along with the popliteal vessels, between the heads of gastrocnemius; the common peroneal nerve disappearing underneath peroneus longus. We’ll look at the tibial nerve first. To follow it, we’ll remove two muscles which it supplies: gastrocnemius, and soleus
The tibial nerve follows the same course as the posterior tibial artery. The nerve passes beneath the flexor retinaculum just behind the artery. Beneath the flexor retinaculum, the tibial nerve divides, into the medial plantar nerve, and the lateral plantar nerve. We’ll see where these go in the next section.
In the leg, the tibial nerve supplies gastrocnemius, plantaris, soleus, and all three of the deep flexor muscles, including tibialis posterior.
Now we’ll follow the common peroneal nerve. As it passes under the peroneus longus muscle, the common peroneal nerve divides, into the superficial peroneal nerve, and the deep peroneal nerve. The superficial peroneal nerve runs down beneath peroneus longus. It emerges here, and continues down to the foot as a sensory nerve, as we’ll see in the next section. The superficial peroneal nerve supplies peroneus longus, and peroneus brevis.
The deep peroneal nerve runs under peroneus longus, here it is again, and then under this adjoining muscle, which is extensor digitorum longus. Here’s the deep peroneal nerve emerging, just medial to the anterior tibial vessels, and medial to tibialis anterior. The deep peroneal nerve follows the same course as the anterior tibial vessels, as it runs down the leg, and under the extensor retinaculum.
Of the muscles that we’ve already seen in the leg, the deep peroneal nerve supplies: tibialis anterior, and peroneus tertius.