Soleus

Soleus

The soleus is a powerful, wide, and flat muscle located in the back of your lower leg, specifically deeper than the gastrocnemius muscle. It extends from just below the knee, running down the lower leg, and connects to your Achilles tendon above your heel. While closely connected to the gastrocnemius, some anatomists consider them a single muscle called the triceps surae.

The primary action of the soleus is plantar flexion of the foot (pointing the toes downward), which is vital for walking, running, and maintaining balance. It plays an important role in standing posture, preventing the body from falling forward. The soleus also acts as a "skeletal muscle pump," assisting in pumping venous blood back to the heart from the periphery, and is particularly effective for plantar flexion when the knee is bent.