Which bone is classified as part of the axial skeleton?

The sphenoid bone is classified as part of the axial skeleton because it is located in the skull, which is a key component of the axial skeleton. The axial skeleton consists of the bones of the head and trunk, including the skull, vertebral column, ribs, and sternum. The sphenoid bone is positioned centrally in the skull and contributes to the cranial floor as well as forming part of the eye sockets. Its complex shape also serves to connect with several other cranial bones, highlighting its importance in overall skull structure.

In contrast, the clavicle and scapula, which are part of the shoulder girdle, belong to the appendicular skeleton. The tarsals, located in the ankle, are also classified as part of the appendicular skeleton. Thus, the position and function of the sphenoid bone within the skull directly correlate with its classification as part of the axial skeleton.