The heel bone is the largest tarsal bone of the foot and is an irregular rectangular structure consisting of a thin layer of bone cortex surrounded by abundant cancellous bone. The heel bone is irregular in shape, with six facets and four articular surfaces, above which there are three articular surfaces, the anterior, middle, and posterior talocalcaneal surfaces, which articulate with the anterior, middle, and posterior heel surfaces of the talus, respectively, to form the subtalar joint. Between the middle and posterior subtalar joints there is a groove with a wide lateral opening called the epiphyseal sinus. The anterior aspect of the heel bone has a protrusion as the anterior tuberosity of the heel bone, and the divergent ligaments start from the tuberosity and end at the dice bone and navicular bone. The anterior articular surface of the calcaneus is saddle-shaped with the associated nodes of the dice bone, and the posterior portion of the calcaneus is enlarged and migrates downward to the calcaneal tuberosity, where the Achilles tendon attaches. Its metatarsal surface has two projections, the medial and lateral eminences, which are the metatarsal fascia and the starting point of the plantar tuberosity. Achilles fractures can occur when the heel bone is subjected to direct violence, and are particularly susceptible to comminuted heel fractures.