The triceps surae muscle is located on the posterior side of leg, allowing us to walk on tiptoe and jump. Broad and powerful, it is composed of two well defined portions: the gastrocnemius and the soleus muscle, both being united into one by the Achilles tendon, which is inserted into the calcaneus (heel bone).
It is called ‘triceps’ because the former consists of two strong heads, which protrudes sideways in athletes, plus the latter, which lies underneath it. Lying on top of the soleus, both heads of the gastrocnemius originates from the distal end of femur, while the soleus arises from the upper portion of fibula and the shaft of tibia.
Action/function
The triceps surae is the muscle of athletes and ballet dancers as it accomplishes plantar flexion of the foot, pulling its tip downwards (when we are sitting) and raising the heel off the ground (when we are standing), allowing us to jump or walk in tiptoe.
Nerve Supply
It is innervated by the medial popliteal nerve (L4, L5; S1, S2), which originates from the sciatic.
Blood Supply
The triceps surae muscle receives oxygenated blood from the posterior tibial and peroneal artery.
Below, an schematic drawing the muscles of posterior aspect of leg, showing the gastrocnemius and the soleus muscle.
