soleus muscle so·le·us muscle (sō'lē-əs)
A muscle with origin from the head and shaft of the fibula, the medial margin of the tibia, and the tendinous arch passing between the tibia and fibula, with insertion into the tuberosity of the calcaneus, with nerve supply from the tibial nerve, and whose action causes plantar flexion of the foot.
a flat, broad muscle of the calf of the leg lying just beneath the gastrocnemius muscle. It arises from the upper portions of the tibia and fibula, the bones of the lower leg, and then joins with the gastrocnemius to attach via the Achilles tendon at the heel. Its major action is flexion of the ankle joint, particularly when the leg is bent at the knee, thereby extending the foot downward
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