Gastrocnemius muscle.
Get Fit Today UK
In humans, the gastrocnemius muscle is a very powerful superficial muscle that is in the back part of the lower leg and also called the calf. It runs from its two heads just above the knee to the heel, and is involved in standing, walking, running and jumping. Along with the soleus muscle it forms the calf muscle.
The gastrocnemius is located with the soleus in the superficial posterior compartment of the leg. It originates from the posterior (back) surfaces of the distal head of the femur. Its other end forms a common tendon with the soleus muscle; this tendon is known as the calcaneal tendon or Achilles Tendon and inserts onto the posterior surface of the calcaneus, or heel bone.
This article was originally based on an entry from a public domain edition of Gray's Anatomy.