Which peroneal muscle is NOT supplied by the superficial peroneal nerve?

The peroneus tertius muscle is innervated by the deep peroneal nerve rather than the superficial peroneal nerve, which is why it is the correct choice in this context. The deep peroneal nerve primarily innervates the anterior compartment of the leg, which includes the tibialis anterior, extensor digitorum longus, and peroneus tertius. In contrast, the superficial peroneal nerve is responsible for innervating the lateral compartment muscles, specifically the peroneus longus and peroneus brevis.

Understanding the innervation of these muscles can help in differentiating their functions and anatomical locations. The peroneus longus and peroneus brevis work together to evert and plantarflex the foot, while the peroneus tertius, which is more of an extension of the anterior compartment, assists in dorsiflexion and may also contribute to eversion. The extensor digitorum longus, also supplied by the deep peroneal nerve, extends the toes and helps in dorsiflexion as well.

Focusing on the innervation of these muscles enhances the understanding of their clinical relevance and potential implications in cases of nerve injury or compartment syndromes.