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Figure 3-2.—Sutures of a skull.
Table 3-1.—Bones of the Cranium
Single Bones
Paired Bones
Occipital
Parietal
Frontal
Temporal
Sphenoid
Ethmoid
the nasal cavity. In children, the frontal bone develops
as two parts. They are usually fused together by age 5
or 6. The two frontal sinuses (air spaces in the bone)
are located above each eye socket.
Parietal Bones
The two parietal bones are located behind the
frontal bone. These bones form the greater part of the
right and left sides and the roof of the skull. They each
have four borders and are shaped like a curved plate.
Temporal Bones
The temporal bones form the sides and part of the
base of the skull in the area of the ear. One temporal
bone is located on each side of the head. It is readily
recognized as “fan-shaped.” Each encloses the internal
ear structures and have depressions called glenoid
fossae that forms the articulation with the mandible.
Figure 3-3.—Cranial bones.
The zygomatic process of the temporal bone
projects out into the zygomatic bone of the face and
forms the lateral part of the zygomatic arch. Both the
glenoid fossae and zygomatic process can be seen in
figure 3-4.
Occipital Bone
The occipital bone forms the back part of the skull
and the base of the cranium. It joins with the parietal
and temporal bones. In the center, underside (inferior)
portion of the cranium, there is a large opening called
the foramen magnum (fig. 3-5), through which nerve
fibers from the brain pass and enter into the spinal cord.
Figure 3-4.—Temporal bone.
3-2
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