Skull Health Article

Paired facial bones

Paired facial bones include the lacrimals, nasals, zygomatics, maxillae, palatines, and inferior nasal conchae.

The lacrimal bones are the smallest and most fragile of the facial bones and they are paired left and right. They help form the back portion of each eye socket, and are rectangular in shape with two surfaces and four borders. The lacrimals contain a feature, called the lacrimal sulcus, which helps to form the lacrimal fossa. The lacrimal fossa is an opening for the lacrimal ducts that connects the corner of the eye to the nasal passage, and allows the tears from the eye to be channeled into the nose. The lacrimals make contact with the following bones: frontal, ethmoid, and maxillae.

Each nasal bone is a small rectangular bone. Together they form the bridge of the nose above the nasal cavity. They join with each other along the internasal suture and with the frontal bone above along the fron-to-nasal suture. The point of intersection of both sutures is called the nasion. Nasal bones make contact with the following bones: frontal, maxilla, and other nasals.

The zygomatics are the cheek bones. They have three major features that connect them with surrounding bones. The first is the frontal process. The frontal process forms the wall of the eye socket and connects above with the zygomatic process of the frontal bone. This section separates the eye orbit from the temporal fossa and has a projection called the marginal process. The third feature is the temporal process, and it connects with the zygomatic process of the temporal bone. Together these processes help to form the zygomatic arch which is the attachment for the masseter muscle, one of the major muscles used for chewing (mastication). The zygomatics make contact with the following bones: frontal, sphenoid, maxillae, and temporals.

The maxillae are also paired facial bones. They seat the upper teeth and form the upper jaw. In the upper part of the bone, the frontal process helps to form the nasal opening and ends by connecting with the frontal bone. A maxilla makes contact with the following bones: frontal, ethmoid, zygomatic, vomer, lacrimal, maxilla, nasal, palatine, mandible, and inferior nasal concha.

The palatines are paired left and right and connect with each other along the interpalatine suture. Both bones help form the back section of the hard palate as well as a portion of the nasal cavity. A palatine bone makes contact with the following bones: sphenoid, ethmoid, maxilla, vomer, and the other palatine bone.

The inferior nasal conchae are very thin and delicate paired bones that are elongated with curled-up ends. They are attached to the sides of the nasal cavity and connect to the maxilla and the bones that form the side wall of the nasal cavity. An inferior nasal concha makes contact with the following bones: ethmoid, lacrimal, maxilla, and palatines.

Unpaired facial bones

The unpaired facial bones include the vomer, mandible, and hyoid.

The vomer is a single flat bone. The upper part connects with the perpendicular plate of the ethmoid to form the nasal septum, the dividing wall that runs down the middle of the nose. The vomer makes contact with the following bones: sphenoid, ethmoid, palatines, and maxillae.

The largest facial bone is the mandible. It is the only bone of the skull that contains a movable joint. It is a strong, curved-shaped bone that encases the lower teeth in the alveolar process. It has rounded projections, called mandibular condyles on each end. The condyles link it to the temporal bone by hinges called the temporomandibular joints. The mandible makes contact with the following bones: temporals and maxillae.

The hyoid is a single small U-shaped bone that does not join with any other bone. It hangs from the styloid process of each temporal bone by means of ligaments.