The soleus muscle is a flat skeletal muscle which is located on the posterior side of leg. It lies under the gastrocnemius and it can only be partially noticed at the medial and lateral aspect of leg.
The soleus muscle arises from the head and upper third of the shaft of fibula, and also from soleal line and the middle third of the shaft of tibia. Then this muscle stretches down towards the heel as it becomes narrower.
In the lower third portion of leg, the soleus muscle fuses together with the gastrocnemius, ending up in a powerful thick tendon; the Achilles’ tendon, which is inserted into the posterior surface of the calcaneus of tarsus (heel bone).
Action/function
The soleus muscle works in unison with the gastrocnemius, performing plantar flexion of the foot as they pull its tip downwards (like a ballet dancer). When one is standing, it raises the heel off the ground.
Innervation
This leg muscle is innervated by the tibial nerve (L4, L5; S1, S2), which arises from the sciatic.
Blood Supply
The soleus is supplied by branches of the posterior tibial and peroneal artery.
Below, an anatomical drawing which shows both the gastrocnemius and the soleus muscle beneath it.
