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1-3 BONES OF THE FACE

The facial skeleton consists of 14 stationary bones and a mobile lower jawbone (mandible). These 14 bones (table 1-2) form the basic shape of the face, and are responsible for providing attachments for muscles that make the jaw move and control facial expressions. Figures 1-8 and 1-9 show the bones of the face.

Table 1-2.—Bones of the Face

Figure 1-8.—Anterior view of facial skeleton.

Figure 1-9.—Posterior view of facial skeleton.

Maxillae Bones

The maxillae bones are the largest bones of the face and together form the upper jaw. The maxilla (singular) consists of a body and. four processes: zygomatic, frontal, alveolar and palatine. The maxilla forms the hard palate, floor of the nose, part of the orbits (eye sockets), and the tooth sockets of the upper teeth. Above the roots of the upper teeth and below the floor of the orbits are the maxillary sinuses; the largest of the sinuses.

Palatine Bones

The palatine bones are located behind the maxillae (fig. 1-10). The bones are somewhat L-shaped and form the posterior portion of the hard palate and the floor of the nose. Anteriorly, they join with the maxillary bone.

Figure 1-10.—Anterior view of palatine bones.

Zygomatic Bones (Zygoma, Malar Bone)

The zygomatic bones make up the prominence of the cheeks and extend from the zygomatic process of the temporal bone to the zygomatic process of the maxilla. The zygomatic bones form the "cheek bones" and help to form the sides and floor of the orbits.

Lacrimal Bones

The lacrimal bones are the smallest and most fragile of the cranial bones. These thin, scalelike structures are located in back of the frontal process of the maxilla.

Nasal Bones

The nasal bones are small oblong bones somewhat rectangular in shape. They lie side by side and are fused at the midline to form the bridge of the nose (nasal septum). These bones are responsible for the shape of the nose.

Inferior Nasal Conchae

The inferior nasal conchae are curved, fragile, scroll-shaped bones that lie in the lateral walls of the nasal cavity. They provide support for mucous membranes within the nasal cavity.

Vomer Bone

The vomer bone is a thin, flat, single bone almost trapezoid in shape. It connects with the ethmoid bone and together they form the nasal septum.

Mandible

The mandible (lower jaw-bone) is the longest, strongest, and the only movable bone in the skull. Figure 1-11 illustrates the anatomy of the mandible.

Figure 1-11.—Anatomy of the mandible; lateral view (left), inferior view (right).

The mandible is horseshoe-shaped, with an upward sloping portion at each end called the ramus. The rami are divided into two different processes:

• Condyloid process—Also called mandibular condyle, located posterior on the ramus and forms the head of the mandible. It is knuckle-shaped, and articulates in the glenoid fossa of the temporal bone to form the temporal mandibular joint.
• Coronoid process—Located anterior of the condyle, and provides attachment for the temporal’s muscle, which helps lift the mandible to close the mouth.
• Other important anatomical landmarks of the mandible you should be able to recognize are as follows:
• Alveolar process—Supports the teeth of the mandibular arch.
• Mental protuberance—Also referred to as the chin and is located at the midline of the mandible.
• Mental foramen—Located on the facial surfaces of the mandible on both the right and left sides, just below the second premolars. This opening contains the mental nerve and blood vessels.
• Body—The heavy, horizontal portion of the mandible below the mental foramen extending from the angle to the parasyplysis region.
• Angle—Juncture where the body of the mandible meets with the ramus.
• Mandibular foramen—Located near the center of each ramus on the medial side (inside), through this opening passes blood vessels and the interior alveolus nerve, which supply the roots of the mandibular teeth. This is a common area where the dental officer will inject anesthetic to block the nerve impulses and make the teeth on that side insensitive (numb).

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