The Achilles tendon attaches the calf muscles–the gastrocnemius and the soleus–to the heal (calcaneus). It assists in the flexion of the foot such as pushing off the ball of the foot or pulling the foot upward.

Injuries can range from partial tears to complete ruptures. Complete ruptures are usually accompanied by a load pop or snapping sound, the inability to stand on the toes, a gap where the tendon usually resides, and swelling.