Our calf muscles are actually made of 2 different muscles: your gastrocnemius and your soleus
Both are powerful muscles responsible for plantar flexion (pointing your toe) and are vital muscles in walking, running, and keeping balance.
Due to their location and important role in both movement and balance, the calf muscles can often become tight and injured while playing sport. They take a lot of load and impact especially in sports that involve a lot of running. Long distance runners and sprinters are both susceptible to calf injuries, although the nature of the injury may vary.
The gastrocnemius is your larger calf muscle, forming the bulge that is visible beneath your skin. The gastrocnemius has two parts or “heads,” which combined together create its diamond shape.The soleus is your smaller, flat muscle that is often overlooked because it’s hiding behind your gastrocnemius.
Collectively, the muscles work to plantarflex and invert the foot.
They are innervated by the tibial nerve, a terminal branch of the sciatic nerve. Plantarflexion is a movement required in jumping, running and walking. The gastrocnemius is the powerful muscle that enables plantarflexion, as well as knee flexion.
This region of the lower leg is made up three main compartments, anterior, posterior and lateral compartments. The posterior compartment of the leg contains seven muscles, organised into two layers – superficial and deep. The two layers are separated by a band of fascia.
The gastrocnemius (calf) is the most superficial of all the muscles in the posterior compartment also known as the flexor compartment and lies superficial to the soleus muscle. The plantaris muscle runs between both of them. It has two heads – medial and lateral, which converge to form a single muscle belly.
The two heads of the gastrocnemius muscle form the inferior medial and lateral boundaries of the popliteal fossa in the upper part of the posterior leg. Almost the entire superficial surface of the muscle is covered by deep fascia over which lies the short saphenous vein. The common peroneal nerve passes posterior to the lateral head.