The gastrocnemius is the most superficial calf muscle and makes up the bulk of the visible calf contour. It has two heads—a medial and a lateral head—that both originate just above the knee, from the posterior surfaces of the femoral condyles. These heads merge into a common tendon, which joins the soleus to form the Achilles tendon. This tendon inserts into the posterior aspect of the calcaneus. Because it crosses both the knee and the ankle, the gastrocnemius functions as a knee flexor and an