The calcaneus, commonly known as the heel bone, is classified as an irregular bone. This categorization comes from its complex shape, which does not fit into the typical definitions of long, short, or flat bones. Irregular bones have shapes that provide support and structure, and the calcaneus plays a crucial role in bearing the weight of the body and facilitating movement.
As for the skeleton it belongs to, the calcaneus is a part of the appendicular skeleton. The appendicular skeleton comprises the bones of the limbs and their attachments to the axial skeleton, which includes the skull, vertebral column, and rib cage. The calcaneus is located in the foot, connecting the leg to the foot and contributing to the overall structure and function of the appendicular skeleton.