Final answer:
The skull includes the cranium, which has eight bones that protect the brain and provide head structure. The sides and base of the skull involve the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones, fused by connective tissue.
Step-by-step explanation:
The cranium, or braincase, is a vital part of the human skull that serves the dual purpose of protecting the brain and providing structural support for the head. Comprising eight bones, the cranium forms the sides and some of the base of the skull, creating a protective enclosure for the brain.
The frontal bone forms the forehead, while the two parietal bones contribute to the top and sides of the skull. The temporal bones, located on each side, house the ear structures. The occipital bone forms the back and base of the skull, featuring the prominent external occipital protuberance. The sphenoid bone, centrally positioned, plays a pivotal role in structuring the eye sockets (orbits) and contributes to the complex floor of the cranial cavity. The ethmoid bone, also part of the cranial floor, is situated anteriorly to the sphenoid and contributes to the nasal cavity structure.
In adulthood, these cranial bones are tightly fused through dense fibrous connective tissue, forming a solid and protective structure for the brain. The sphenoid bone, with its multiple processes, helps create the bony framework for the orbits, while the ethmoid bone provides structural support to the anterior cranial floor.
The parietal and temporal bones contribute significantly to the lateral aspects of the skull. Notably, the squamous suture joins the temporal bones with the parietal bones, forming a crucial juncture in the skull's lateral architecture.
Collectively, these cranial bones ensure the protection and stability of the brain while accommodating sensory organs such as the eyes and ears. The intricate fusion of these bones and their specific roles highlight the complexity of the skull's anatomy and its vital functions in safeguarding the delicate organ housed within.