The Tricep Surae muscles more commonly know as the muscles of the calf, comprises of a pair of muscles known as the Gastrocnemius and Soleus muscles, which derive their names from the Latin from the Greek words Gaster (stomach or belly) and Kneme( part of the leg between the knee and ankle) and Soleus from the Latin meaning sandal. The primary function of these two muscles are to work together as plantar flexors (bending the foot back at the ankle joint) as well as flexing the leg at the knee(bending the knee) in addition to assisting propulsion and stabilisation during the actions of walking, running and jumping.
THE GASTROCNEMIUS MUSCLE
The Gastrocnemius muscle lies on top of the Soleus running from the knee to the ankle joints. It is the less powerful plantar flexor when compared with the soleus muscle and comprises of two parts the medial head and the Lateral head. The origin point of the medial head arise from the medial condyle of the femur, and the origin point of the lateral head arises from the the lateral condyle of the femur. The Gastrocnemius muscle forms two bellies which lie side by side and merge mid calf at the Gastrocnemius aponeurosis which eventually merge to into the Tendo Calcaneous and the two heads share the same insertion point with the tendon on the soleus.
THE SOLEUS MUSCLE
The Soleus muscle is a complex multi-pennate muscle that is more powerful than that of the Gastrocnemius muscle and has multiple origin points arising from the posterior head of the fibula and down along a quarter of its shaft, as well as from a fibrous band between the fibula and tibia two and then along the soleal line on the tibia. The soleus muscle fibbers merge into a large tendon which joins with the tendo calcaneous and the tendon for the gastrocnemius muscle before it’s insertion point on the calcaneous bone, the heel bone.