Which structures are included in the axial skeleton?

The axial skeleton comprises the central core structures of the body, primarily focusing on protecting the central nervous system and supporting the body's framework. This includes the skull, vertebral column (spine), and rib cage. The primary function of the axial skeleton is to provide structure and stability to the body.

Ribs and spine are integral components of the axial skeleton. The spine, also known as the vertebral column, supports the head and houses the spinal cord, while the ribs protect vital organs in the thoracic cavity, including the heart and lungs. Together, they contribute to the overall integrity of the axial skeleton.

In contrast, the other choices consist of bones that belong to the appendicular skeleton. For example, the pelvis and femur are involved in limb movement, while the clavicle and scapula are part of the shoulder girdle, and the radius and ulna are forearm bones. These structures are pivotal for limb mobility and do not serve the primary functions associated with the axial skeleton. Thus, the inclusion of ribs and spine as part of this skeletal category is what rightly identifies them with the axial skeleton.