The cranium includes all the bones of the head. Altogether, there are 26 cranial bones plus the mandible. Except for the mandible, these bones mostly are fused together so that they do not move. The joints between most of the cranial bones are borders where the bones knit together, called sutures. The sutures are places where the bones articulate, or contact, each other.
On one of the skulls available, find each of the following bones:
- The bone of the forehead, above the eye sockets, or orbits.
- The two bones (left and right) of the top and sides of the vault.
- The lower sides (left and right) of the vault, including the ear opening, or external acoustic porus.
- Just anterior to the temporal bones, the sphenoid stretches through the skull from left to right.
- The largest bones (left and right) of the face.
- The cheek bones (left and right).
- These bones, left and right, form the bridge of the nose.
- The bone of the lower jaw.
The remaining bones of the skull can be harder to find, and this lab doesn't require you to learn them in detail. Six of them are the tiny bones of the middle ear on both sides. The ethmoid and left and right lacrimal bones are most visible on the medial (inner) surface of the eye orbits. The vomer and left and right inferior conchae are inside the nasal aperture. The larger bones listed above will be the most important for comparing humans with each other and other primates.
The frontal bone articulates with 12 other cranial bones. Three of these are the ethmoid and left and right lacrimal bones. Can you find the other nine?