2-30. THE TEMPOROMANDIBULAR JOINT
The temporomandibular articulation (joint) is formed by the condyle of the
mandible and the mandibular fossa of the temporal bone. It is of the ginglymoarthrodial
variety of joint.
2-31. ASPECTS OF THE SKULL
a. Anterior Aspect. When considered as a whole and viewed from the anterior
or frontal aspect, the skull presents the following bony parts (figure 2-27). The forehead
is formed by the squama of the frontal bone and exhibits two arched elevations (the
superciliary arches). Beneath each superciliary arch is a curved and prominent margin,
the supraorbital margin, in which is the supraorbital notch, or foramen. The supraorbital
margins are joined medially to form the glabella. The zygomatic bone forms the
prominence of the cheek. The infraorbital margin is formed by the zygomatic bone and
the maxilla. The eyes are embedded in orbits. Each orbit is a pyramid-shaped cavity
that has four walls, an apex, and a base that is formed by the supraorbital and
infraorbital margins. The frontal and ethmoidal bones form the superior wall, or roof.
The maxillary, zygomatic, and palatine bones form the inferior wall, or floor. The
zygomatic and splenoid bones form the lateral wall. The medial wall is formed by the
maxillary, lacrimal, and sphenoid bones. At the apex of the orbit is the optic canal (a
short, cylindrical canal that transmits the optic nerve and the ophthalmic artery). The
inferior orbital fissure, which transmits nerves and blood vessels, is situated at the
junction on the floor and the lateral wall of the orbit. At the junction of the roof and the
lateral wall, near the apex of the orbit, is the supraorbital fissure, which transmits
several nerves.
b. Lateral Aspect. The frontal, parietal, occipital, temporal, sphenoidal,
ethmoidal, lacrimal, nasal, maxillary, zygomatic, and mandibular bones are partly visible
in the lateral view of the skull (figure 2-29). The prominent zygomatic arch
(figure 2-30), which is formed by the temporal process of the zygomatic bone and the
zygomatic process of the temporal bone, should be noted. Posterior to the zygomatic
process is the opening of the external acoustic(auditory) meatus (EAM) of the temporal
bone. Posteroinferior to the external acoustic meatus is the mastoid process.
MD0956
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