A&P Chap 5 Facial Skeleton

Inferior nasal conchae

are fragile, scroll-shaped bones attached to the lateral walls of the nasal cavity. They are the largest of the conchae and are positioned below the superior and middle nasal conchae of the ethmoid bone. Like the ethmoidal conchae, the inferior conchae support mucous membrane within the nasal cavity

Nasal bones

are long, thin, and nearly rectangular. They lie side by side and are fused at the midline, where they form the bridge of the nose. These bones are attachments for the cartilaginous tissues that form the shape of the nose

Maxillary bones

form the upper jaw; together they form the keystone of the face, since all the other immovable facial bones articulate with them. Portions of these bones comprise the an tori or the roof of the mouth (hard palate), the floors of the orbits, and the sideband floor of the nasal cavity. They also contain the sockets of the upper teeth. MAXILLARY SINUSES, these spaces are the largest of the sinuses, and they extend from the floor of the orbits to the roots of the upper teeth. During development, portions of the maxillary bones called palatine processes grow together and fuse along the midline, or median palatine suture. This forms the anterior section of the hard palate. The inferior border of each maxillary bone projects downward, forming an alveolar process. Together these processes from a horseshoe-shaped alveolar arch (dental arch). Teeth occupy cavities in this arch (dental alveoli). Dense connective tissue binds teeth to the bony sockets.

Lacrimal bones

is a thin, scalelike structure located in the medial wall of each orbit between the ethmoid bone and the maxilla. A groover in its anterior portion leads from the orbit to the nasal cavity, providing a pathway for a channel that carries tears from the eye to the nasal cavity

Mandible

or lower jawbone, is a horizontal, horseshoe-shaped body with a flat ramus projecting upward at each end. The rami are divided into a posterior MANDIBULAR CONDYLE and an anterior CORONOID PROCESS. The mandibular condyles articulate with the mandibular fosse of the temporal bones, whereas the coronoid processes provide attachments for muscles used in chewing. Other large chewing muscles are inserted on the lateral surfaces of the rami. A curved bar of bone on the superior border of the mandible, the alveolar border, contains the hollow sockets (dental alveoli) that bear the lower teeth. On the medial side of the mandible, near the center of each rams, is a MANDIBULAR FORAMEN. This opening admits blood vessels and a nerve, which supply the roots of the lower teeth. Dentists inject anesthetic into the tissues near this foramen to temporarily block nerve impulse conduction and desensitize teeth on that side of the jaw. Branches of the blood vessels and the nerve emerge from the mandible throughout the MENTAL FORAMEN, which opens on the outside near the point of the jaw. They supply the tissues of the chin and lower lip.

Palatine bones

the L-Shaped palatine bones are located behind the maxillae. The horizontal portions form the posterior section of the hard palate and the floor of the nasal cavity. The perpendicular portions help form the lateral walls of the nasal cavity.

Vomer bone

the thin, flat vomer bone is located along the midline within the nasal cavity. Posteriorly, it joins the perpendicular plate of the ethmoid bone, and together they form the nasal septum

Zygomatic bones

they are responsible for the prominences of the cheeks below and to the sides of the eyes. These bones also help form the lateral walls and the floor of the orbits. Each bone has a TEMPORAL PROCESS, which extends posteriorly to join the ZYGOMATIC PROCESS of a temporal bone. Together these processes for a ZYGOMATIC ARCH