Answer
The cranium is the bony box that contains the brain . It is composed of 8 bones -- one frontal bone, two parietal bones, two temporal bones,, one sphenoid bone, one ethmoid bone, and one occipital bone.
The bones are joined by suture joints and are separated from brain tissue by the meninges-- dura mater ( outer most meninx) the arachnoid mater and the pia mater, the innermost meninx. . Much of the dura lies loosely against the skull, but it is attached at a few points
There are several foramina or openings into the skull. Of these the foramen magnum is the largest . It is at the site where the spinal cord meets the medulla oblongata of the brain. The dura is attached to the foramen magnum.
Work Step by Step
The two major divisions of the cranium are the calvarium, and the base. The calvarium--dome or top of head-- is not a single bone, but parts of several bones that form the roof and the walls of the cranial cavity.
The base or floor of the cranium is composed of the following depressions or cranial fossae. :
1. The shallow anterior fossa accommodates the frontal lobes.
2. The middle cranial fossa accommodates the temporal lobes and
the hypothalamus.
3. The posterior cranial fossa, the deepest, houses the
cerebellum, pons and medulla oblongata..
