The calcaneus, also called the heel bone, is a large bone that forms the foundation of the rear part of the foot. The calcaneus connects with the talus and cuboid bones. The connection between the talus and calcaneus forms the subtalar joint. This joint is important for normal foot function.
The calcaneus is often compared to a hard boiled egg, because it has a thin, hard shell on the outside and softer, spongy bone on the inside. When the outer shell is broken, the bone tends to collapse and become fragmented. For this reason, calcaneal fractures are severe injuries. Furthermore, if the fracture involves the joints, there is the potential for long-term consequences such as arthritis and chronic pain.