The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus. These muscles both insert into the calcaneus, the bone of the heel of the human foot, and form the major part of the muscle of the back part of the lower leg, commonly known as the calf muscle. The triceps surae is connected to the foot through the Achilles tendon, and has 3 heads deriving from the 2 major masses of muscle. The superficial portion (the gastrocnemius) gives off 2 heads attaching to the base of the femur directly above the knee. The deep (profundis) mass of muscle (the soleus) forms the remaining head which attaches to the superior posterior area of the tibia. The triceps surae is innervated by the tibial nerve, specifically, nerve roots L5-S2. [WP,unvetted]. [ http://en.wikipedia.org/wiki/Triceps_surae_muscle ]