The calcaneus, commonly known as the heel bone, is the largest bone in the foot and forms the foundation of the rear part of the foot. It plays a crucial role in weight-bearing and provides leverage for walking and running. The bone articulates with the talus above and the cuboid in front, contributing to the foot's overall structure and stability. Additionally, the calcaneus serves as an attachment point for various muscles and ligaments, including the Achilles tendon.