Figure 2-36. Suture joints of the skull (lateral aspect).
c. Zygomatic Bones. The two zygomatic, or malar bones (figures 2-27 and
2-28) form the prominence of the cheeks and contribute to the lateral walls and floor of
the orbits. Each zygomatic bone has several processes: the frontal (which projects
superiorly), the temporal (which projects posteriorly), and the maxillary (which projects
anteriorly and medially).
d. Maxillae. The upper jaw is formed by the union of the two maxillary bones
(figures 2-27, 2-28, 2-29, and 2-30). Each maxilla assists in forming the boundaries of
the nasal cavity (the floor and lateral wall), the oral cavity (the roof), and the orbit (the
floor). Each maxilla consists of a body and four processes: zygomatic, frontal, alveolar,
(1) The body contains a large cavity, the maxillary sinus (figure 2-35) or
antrum of Highmore. The anterior surface of the body is perforated by the infraorbital
foramen, which transmits nerves and blood vessels. Medially and anteriorly, there is a
sharp process that, with its fellow of the opposite side, constitutes the anterior nasal
spine. The top of the body, the orbital surface, is a smooth, triangular surface that
forms the greater part of the floor of the orbit. The nasal surface presents a large
opening that leads into the maxillary sinus. The deep lacrimal groove is situated in front
of the sinus opening. This groove, along with the lacrimal bone, constitutes the canal
that transmits the nasolacrimal duct. Tears from the lacrimal sac of the eye are drained
through the nasolacrimal duct into the nasal cavity.