Triceps suræ

The triceps surae is a term given by some anatomists to the gastrocnemius and soleus muscles together as they 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 (the calf; otherwise known in Latin as the sura, see also the sural nerve).

Considering these 2 muscles as one, the triceps surae inserts into the Achilles' tendon (tendo calcanei) 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.