Skull bone of animals

The bones of the skull are divided into cranial and facial groups. The former enter into the formation of the cranium, which lodges the brain and the essential organs of hearing while the latter form the boundaries of the oral and nasal cavities and also support the pharynx, larynx and tongue. The two sets together form the orbits. Some of the bones are also forming sinuses and they are called as paranasal sinuses.

The cranial bones are parietal, interparietal, occipital, sphenoid, ethmoid, temporal and frontal. Of these, occipital, sphenoid, ethmoid are unpaired.

The Facial bones are nasal, premaxilla, maxilla, palatine, pterygoid, lacrimal, malar, turbinates, vomer, mandible and hyoid.

Most of the bones of the skull are flat bones developed in membrane. Those of the cranial base may be classified as irregular and are developed in cartilage. Occipital, sphenoid, ethmoid, petro-mastoid parts of temporal and turbinates develop in cartilage. Others develop in membrane.

Wormian or Sutural bones are small irregular bones situated in the sutures of the cranial bones. They are developed after birth in the cranial, cranio-facial and facial sutures. Their number and position varies with the species of animals and even in the breeds of the same species.

Cranial wormian bones are rare. When seen, they are at the junction of the petrous-temporal with the occipital bone. The wormian bones of the cranio-facial and facial sutures are more frequent. They are more particularly met with in the bovine species in the fronto-nasal, internasal, lacrymo-nasal, zygomatico-maxillary, orbital and maxillo-nasal incisive sutures.

Skull of the pig and skull of the rabbit are described separately for the convenience.