Achilles tendon Strong band of elastic connective tissue at the back of the ankle. One of the largest tendons in the human body, it connects the calf muscles to the heel bone. The spring it provides is very important in walking, running and jumping.

Achilles tendon (ă-kil-eez) n. the tendon of the muscles of the calf of the leg (the gastrocnemius and soleus muscles), situated at the back of the ankle and attached to the calcaneus (heel bone).