In humans, the calcaneus (/kælˈkeɪniːəs/; from the Latin calcaneus or calcaneum, meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock.
In humans, the calcaneus is the largest of the tarsal bones and the largest bone of the foot. The talus, calcaneus, and navicular are considered the proximal row of tarsal bones. In the calcaneus, several important structures can be distinguished:
The half of the bone closest to the heel is the tuber calcanei. On its lower edge on either side are its lateral and medial processes (serving as the origins of the abductor hallucis and abductor digit minimi). The calcaneal (Achilles) tendon is inserted into a roughened area on its superior side, the cuboid bone articulates with its anterior side, and on its superior side are three articular surfaces for the articulation with the talus bone. Between these superior articulations and the equivalents on the talus is the tarsal sinus (a canal occupied by the interosseous talocalcaneal ligament). On the medial side of the bone, below the middle talar facet, is the sustentaculum tali (which serves for the attachment of several other ligaments). On the lateral side is commonly a tubercle called the peroneal trochlea, under which is a groove for the tendon of the peroneus longus.
The calcaneus is part of two joints: the proximal intertarsal joint and the talocalcaneal joint. The point of the calcaneus is covered by the calcanean bursa.
Normally the tibia sits vertically above the calcaneus (pes rectus). If the calcaneal axis between these two bones is turned medially the foot is in an everted position (pes valgus), and if it is turned laterally the foot is in an inverted position (pes varus).
3D rendering of a left calcaneus derived from CT scan data. The calcaneus is white, and the other bones of the foot and ankle are clear to illustrate the position and relationship of the calcaneus to the other tarsal bones.
^Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). pp. 364–367. ISBN978-87-628-0307-7.|accessdate= requires |url= (help)