Achilles' tendon ( tendo calcaneus )tĕnˈdō kălkāˈnēəs, sinew prominent at the back of the ankle, connecting the tendons of the calf muscles to the heelbone. When the musculature contracts, the pull on the Achilles' tendon elevates the heel in the springy motion essential to running and jumping. Since the effect is to lift the entire body weight against a severely adverse leverage ratio, the Achilles' tendon by necessity is the toughest and strongest of human tendons. The name derives from the mythical Greek hero Achilles, who was vulnerable only in the heel.
More on Achilles' tendon from Fact Monster:
See more Encyclopedia articles on: Anatomy and Physiology