Dorsiflexion of the foot. Artwork of the muscles of the foot from the side, with red arrows showing the direction of movement when flexing the foot in the direction of its upper (dorsal) surface (dorsiflexion). The muscles involved are the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius. These muscles arise in the lower leg, and extend downwards into the foot. The nerve used is the common peroneal nerve. This is the left foot. For the right foot, see C016/6797.