The bone that forms the prominence of the heel is a foundational component of the lower limb structure. It is situated at the back of the foot, serving as the initial point of contact with the ground during walking and running. Its robust structure supports the body’s weight and manages the forces involved in movement. This irregularly shaped bone is located just beneath the ankle joint, defining the shape of the hindfoot.
The Calcaneus
The other name for the heel bone is the Calcaneus, which is its formal anatomical designation. This term is derived from the Latin word calcaneum, which directly translates to “heel.” As the largest of the seven tarsal bones, the calcaneus is a substantial, roughly cuboidal structure located in the hindfoot.
It is uniquely positioned beneath the talus bone and extends backward to create the recognizable contour of the heel. The calcaneus is proportionally the largest bone in the entire foot, and its size is necessary for accepting and distributing significant body loads. Its internal architecture includes a unique trabecular pattern that helps maximize strength.
The bone’s superior surface features several facets that articulate with the talus bone directly above it. The inferior aspect provides attachment sites for numerous ligaments and muscles that support the arch of the foot.
Load Bearing and Connection to the Ankle
The calcaneus functions as the primary weight-bearing structure in the foot, transferring the body’s force from the leg to the ground with every step. It acts as a natural shock absorber, particularly through the thick fat pad that sits directly beneath it. The strategic positioning of the calcaneus forms the mechanical base for the entire lower extremity.
The posterior surface of the calcaneus is the attachment point for the thickest and strongest tendon in the body, the Achilles tendon. This structure connects the powerful calf muscles to the heel bone. This connection allows the calf muscles to pull on the calcaneus, creating the necessary lever action for propulsion during activities like standing on tiptoes, walking, and jumping.
The calcaneus forms an important articulation with the talus bone superiorly to create the subtalar joint. This joint is essential for movements like inversion and eversion of the foot, which allow the foot to adapt to uneven terrain. The articulation is stabilized by strong ligaments, binding the two bones together to manage the rotational forces placed on the ankle.