Which bone is considered part of the facial skeleton rather than the cranium?

The mandible is considered part of the facial skeleton because it is the only movable bone of the skull and plays a key role in the structure of the face. It forms the lower jaw and holds the lower teeth in place, contributing significantly to facial aesthetics and function, including chewing and speaking. Unlike other bones listed, which are part of the cranium, the mandible is specifically associated with the facial structure.

The parietal bone, occipital bone, and sphenoid bone are all components of the cranium, which primarily houses and protects the brain. These bones do not directly contribute to the external contour of the face or support the structures that are part of facial expression and function, making them distinct from the mandible in terms of anatomical classification.