OSTEOLOGY OF THE SKULL

Suture: fibrous bands of tissue that connects the bones of the skull

Canals: is a long tubelike opening through bone

Foramen: is a short tubelike opening through bone

They surround the brain and protect it from injury,

Form the facial skeleton, and

participate in the growth process of the jaws.

the skull is composed of 22 bones. Some of these are single, and some are paired bones

They are grouped into two

Neurocranium,

Viscerocranium

These are bones which surrounds the brains.

It consists of 8 bones some are paired and some are not, which are

Frontal bone: 1

Parietal bones: 2

Occipital bone: 1

Temporal bones: 2

Sphenoid bone: 1

Ethmoid bone: 1

These are bones which forms the face, also called facial bones. It consists of 14 bones, which includes

Zygomatic bones: 2

Maxillae: 2

Nasal bones: 2

Vomer: 1

5). Lacrimal bones: 2

6). Palatine bones: 2

7). Inferior conchae: 2

8). Mandible: 1

The frontal bone, or forehead bone, curves downward to make the upper margins of the orbits. The supraorbital notch, or foramen, can be recognized.

Medially, the frontal bone articulates with the frontal processes of the maxillae and with the nasal bones

Laterally, the frontal bone articulates with the zygomatic bone.

The orbital margins are bounded by the frontal bone superiorly, the zygomatic bone laterally, the maxilla inferiorly, and the processes of the maxilla and frontal bone medially

The two nasal bones form the bridge of the nose. Their lower borders, with the maxillae, make the anterior nasal aperture.

The nasal cavity is divided into two by the bony nasal septum, which is largely formed by the vomer

The superior and middle conchae are from the ethmoid on bone the inferior conchae are separate bones.

The zygomatic bone forms the prominence of the cheek and part of the lateral wall and floor of the orbital cavity.

Medially, it articulates with the maxilla and laterally it articulates with the zygomatic process of the temporal bone to form the zygomatic arch

The two maxillae form the upper jaw, the anterior part of the hard palate, part of the lateral walls of the nasal cavities, and part of the floors of the orbital cavities

Below the orbit, the maxilla is perforated by the infraorbital foramen.

The alveolar process projects downward and, together with the fellow of the opposite side, forms the alveolar arch, which carries the upper teeth

Within each maxilla is a large, pyramid-shaped cavity called maxillary sinus. This serves as a voice resonator.

The frontal bone forms the anterior part of the side of the skull and articulates with the parietal bone at the coronal suture

The parietal bones form the sides and roof,

Articulate with each other in the midline at the sagittal suture.

They articulate with the occipital bone behind, at the lambdoid suture.

parts of the temporal bone, namely, the squamous, tympanic, mastoid process, styloid process, and zygomatic process; and the greater wing of the sphenoid.

In the anterior region the hard palate, which is formed by the palatal processes of the maxillae and the palatal processes of the palatine bones, is visible

Vomer bone can be seen, forming the lower part of the nasal septum.

Just behind that and running the full width of the skull is the sphenoid bone

From this view, portions of the zygomatic bones, the temporal bones, and just a tiny portion of the posterior part of the parietal bones can also be seen.

The mandible is a single bone made up of three parts

The horizontal body,

alveolar process

The ramus.

mental foramen, which blood vessels and nerves for the lower lip and chin emerge

Growth of the mandible.

First, the alveolar process and body increase in width and height. The lengthening of the mandibular arch takes on ramus

about midway up the ramus is the mandibular foramen, where the nerves and blood vessels for the lower teeth and lip enter the mandible

The area immediately behind the third molars is referred to as the retromolar triangle

On the midline there are two projections called mental spines, attachments for muscles that aid in tongue movement and swallowing

The newborn skull compared with the adult skull, has a disproportionately large cranium relative to the face

The bones of the vault are not closely knit at sutures, as in the adult, but are separated by un-ossified membranous intervals called fontanelles (anterior and posterior fontanelles)

The anterior fontanelle is diamond shaped and lies between the two halves of the frontal bone in front and the two parietal bones behind

Closes at age of 18 months

The posterior fontanelle is triangular and lies between the two parietal bones in front and the occipital bone behind

Closes at age of 1 yaer

The mandible has right and left halves at birth, united in the midline with fibrous tissue. The two halves fuse at the symphysis menti by the end of the 1st year.

The angle of the mandible at birth is obtuse