Sutures are firm and immovable joints but allow for expansion of the skull in a growing animal. Distinguish between long bones, short bones, flat bones, and irregular bones and provide an example of each. Many of the bones of the skull are joined together by fibrous joints called sutures (p 41). Introduction to the Skeletal System Learning Objectives Describe the functions of the skeletal system. The incisive bone is the most rostral and carries the incisor teeth (Fig. The roof of the mouth is called the hard palate and is formed from three bones on the ventral aspect of the skull: the incisive bone or premaxilla, part of the maxilla and the palatine. In the centre of this bone is the cribriform plate – a sieve-like area perforated by numerous foramina through which the olfactory nerves pass from the nasal mucosa to the olfactory bulbs of the brain (see Ch. At the back of the nasal chamber, forming a boundary between the nasal and cranial cavities, is the ethmoid bone. These are covered in ciliated mucous epithelium (see Ch. Each of the chambers is filled with delicate scrolls of bone called the nasal turbinates or conchae.

The two layers of compact bone and the interior spongy bone work together to protect the internal organs.

The nasal chamber is divided lengthways into two by a cartilaginous plate called the nasal septum. Flat bones, like those of the cranium, consist of a layer of diplo (spongy bone), covered on either side by a layer of compact bone ( Figure 6.3.3 ). The most rostral part of the skull carries the nasal chamber, the sides of which are formed by the maxilla and the roof by the nasal bone.

Flat bone examples