appendicular skeleton

The appendicular skeleton is the part of the human skeleton that includes the limbs and the girdles that attach them to the axial skeleton. This includes the pectoral (shoulder) girdle, which connects the arms to the trunk, and the pelvic (hip) girdle, which connects the legs to the trunk. The arms and legs have homologous structures, meaning they share a common evolutionary origin and basic plan, but have adapted to different functions.12

The pectoral girdle consists of the scapula (shoulder blade) and clavicle (collarbone), allowing for a wide range of motion in the arms. The pelvic girdle, formed by the ilium, pubis, and ischium, is more rigidly attached to the vertebral column, providing a stable base for the legs and supporting body weight. The limbs themselves contain long bones such as the humerus and femur, as well as the radius, ulna, tibia, and fibula, each adapted for specific functions like weight-bearing and movement.23