Soleus: The soleus is an efficacious muscle in the posterior part of the lower leg muscles(the calf). It arises from just below the knee to the heel, and is involved in standing and walking.
Origin: posterior surface of the head and upper 1/3 of the shaft of the fibula, middle 1/3 of medial border of tibial shaft, and from the posterior surface of a tendinous arch spanning the two sites of bone origin
Insertion: Into calcaneus with gastrocnemius by way of Achilles tendon, inserting in the middle 1/3 of the posterior calcaneal surface.
Function: Powerful plantar flexor of ankle
Nerve Supply: Tibial nerve (S1, S2)