The triceps surae (latin: musculus triceps surae) consists of two muscles and forms the main mass of the calf. The two superficial muscles forming the triceps surae are the gastrocnemius and the soleus.
The gastrocnemius consists of two heads, and the soleus lies under the gastrocnemius.
Each of the muscles has a different site of origin, but both muscles of the triceps surae join their tendons of insertion in the midline of the leg into one tendon, inserting at the calcaneal tuberosity, and it is called the Achilles tendon or the calcaneal tendon.
The triceps surae provides flexion, supination and adduction of the foot, while gastrocnemius also provides flexion at the knee joint, as well as internal and external rotation of the leg.