The appendicular skeleton includes which of the following?

The appendicular skeleton refers specifically to the portion of the skeleton that includes the limbs and the structures that support them. This comprises the pectoral girdle, which connects the upper limbs to the torso, and the bones of the upper and lower limbs themselves. In mammals, the appendicular skeleton plays a critical role in mobility and manipulation of the environment.

Understanding the components of the appendicular skeleton helps clarify its function. The pectoral girdle consists of the scapulae (shoulder blades) and clavicles (collarbones), supporting the arms and enabling a wide range of motion. The bones of the limbs include the humerus, radius, ulna in the arms, and femur, tibia, and fibula in the legs. All these components work together to facilitate movement and interaction with the surroundings.

The other options represent parts of the axial skeleton or combinations that do not align with the definition of the appendicular skeleton. The spine and ribs are part of the axial skeleton, which supports the head and trunk, while the cranium and vertebral column also belong to the axial domain. Facial bones, while part of the skull, do not connect to the limbs and do not define the appendicular skeleton either.