The human skeleton is a collection of approximately 206 bones. It functions as a protective structure for internal organs, an anchor point for muscles and tendons, a reservoir of minerals and home of blood cell-producing marrow. The human skeleton can be divided into regions for easy categorisation.
The axial skeleton consists of the bones that form the central core of the skeleton. These include the skull (22 bones), middle ear (six bones), vertebrae of the spinal column (24 bones), pelvis (four bones), rib cage (24 bones), sternum (one bone) and hyoid bone in the soft tissue of the neck (one bone). The axial skeleton contains a total of 82 different bones.
The upper extremity includes everything from the shoulder to the tips of the fingers. The bones of the upper extremity include the clavicles (two bones), scapulae or shoulder blades (two bones), humerus or upper arm bones (two bones), the radius and ulna of the forearm (four bones) and the bones of the wrists and hands (54 bones). The upper extremities contain a total of 64 bones.
The lower extremity includes everything from the thigh to the toes. The bones of the lower extremity include the femurs or thigh bones (two bones), the kneecaps (two bones), the tibia and fibula of the lower leg (four bones) and the bones of the feet (52 bones). The lower extremities contain a total of 60 bones.