Final answer:
The cranial base is made up of the frontal, ethmoid, sphenoid, temporal, and occipital bones that form the floor of the cranial cavity, subdivided into three fossae offering support and protection to different parts of the brain.
Step-by-step explanation:
The Cranial Base Bones
The bones that make up the cranial base are integral to the structure and protection of the brain within the skull. The base of the skull, forming the floor of the cranial cavity, is composed of several bones, which include the frontal bone, ethmoid bone, sphenoid bone, temporal bones, and the occipital bone. These bones are intricately jointed and do not move relative to each other in adults, being tightly fused with dense connective tissue. The cranial base can be divided into three regions known as the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa, which provide different levels of support and protection for various parts of the brain.
The anterior cranial fossa is the shallowest part and supports the frontal lobes of the brain. The middle cranial fossa, separated from the anterior fossa by the lesser wing of the sphenoid bone, holds the temporal lobes, while the deep posterior cranial fossa accommodates the cerebellum and brainstem, divided from the middle fossa by the petrous ridge of the temporal bone.