Located within the foot, the calcaneus is also known as the heel bone. It is situated in the back of the foot, just below the talus, tibia, and fibula bones of the lower leg. Of all of the bones in the foot, the heel bone is the largest.

The calcaneus has a unique design and structure. At the front, the heel bone features many curves to accommodate the talus and the many different tarsal bones, which lead to the metatarsals and phalanges that make up the front of the foot and toes. The back of the heel bone is not as complex, featuring a tuberosity and a medial process — landmark areas of the bone where muscles attach.

The calcaneus provides insertion points for the abductor hallucis and the abductor digiti minimi muscles. At the back of the heel, the Achilles tendon inserts into the rough area located on the superior (upper) side. This fibrous connective tissue, as well as other ligaments and muscles, is necessary for standing, walking, and running. As such, a broken or fractured calcaneus will make these movements difficult.