The paired bones of the face are the maxillae, palatine bones, zygomatic bones, lacrimal bones, nasal bones, and inferior nasal conchae. The single bones are the vomer and mandible. The maxillae (mak-sil’-e) form the upper jaw. Each maxilla is formed separately, but they are joined at the midline during embryonic development. The maxillae articulate with all of the other facial bones except the mandible. The palatine processes of the maxillae form the anterior portion of the hard palate (roof of the mouth and floor of the nasal cavity), part of the lateral walls of the nasal cavity, and the floors of the orbits.
Each maxilla possesses an inferiorly projecting, curved ridge of bone that contains the teeth. This ridge is the alveolar process, and the sockets containing the teeth are called alveoli (singular, alveolus). The alveolar processes unite at the midline to form the U-shaped maxillary alveolar arch. A large maxillary sinus is present in each maxilla just inferior to the orbits.
The palatine (pal’-ah-tin) bones are fused at the midline to form the posterior portion of the hard palate. Each bone has a lateral portion that projects superiorly to form part of a lateral wall of the nasal cavity.
The zygomatic bones (cheekbones) form the prominences of the cheeks and the floors and lateral walls of the orbits. Each zygomatic bone has a posteriorly projecting process, the temporal process, that extends to unite with the zygomatic process of the adjacent temporal bone. Together, they form the zygomatic arch.
The lacrimal (lak’-ri-mal) bones are small, thin bones that form part of the medial surfaces of the orbits. Each lacrimal bone is located between the ethmoid and maxilla.
The nasal (na’-zal) bones are thin bones fused at the midline to form the bridge of the nose.
The vomer is a thin, flat bone located on the midline of the nasal cavity. It joins posteriorly with the perpendicular plate of the ethmoid, and these two bones form the bony part of the nasal septum.
The inferior nasal conchae are scroll-like bones attached to the lateral walls of the nasal cavity inferior to the middle nasal conchae of the ethmoid. They project medially into the nasal cavity and serve the same function as the superior and middle nasal conchae of ethmoid.
The mandible (lower jaw) is the only movable bone of the skull. It consists of a U-shaped body with a superiorly projecting portion, a ramus, extending from each end of the body. The superior portion of the body forms the mandibular alveolar arch, which contains the alveoli for the teeth. The superior part of each ramus is Y-shaped and forms two projections: an anterior coronoid process and a posterior mandibular condyle. The coronoid process is a site of attachment for muscles used in chewing. The mandibular condyle articulates with the mandibular fossa of the temporal bone to form a temporomandibular joint. These joints are sometimes involved in a variety of dental problems associated with an improper bite.
(93 votes, average: 3.26 out of 5)
Loading...
