Chapter 7—The Skeleton
PART 1: THE AXIAL SKELETON
I. The Skull (pp. 199–216; Figs. 7.1–7.15; Table 7.1)
A. The skull consists of 22 cranial and facial bones that form the framework of the
face, contain cavities for special sense organs, provide openings for air and food
passage, secure the teeth, and anchor muscles of facial expression (p. 200).
B. Except for the mandible, which is joined to the skull by a movable joint, most
skull bones are flat bones joined by interlocking joints called sutures (p. 200).
C. Overview of Skull Geography (p. 200)
1. The anterior aspect of the skull is formed by facial bones, and the remainder is
formed by a cranium, which is divided into the cranial vault, or calvaria, and
2. The cavities of the skull include the cranial cavity (houses the brain), ear
cavities, nasal cavity, and orbits (house the eyeballs).
3. The skull has about 85 named openings that provide passageways for the
spinal cord, major blood vessels serving the brain, and the cranial nerves.
D. The cranium consists of eight strong, superiorly curved bones (pp. 199–209; Figs.
1. The frontal bone articulates posteriorly with the parietal bones via the coronal
suture, extends forward to the supraorbital margins, and extends posteriorly to
form the superior wall of the orbits and most of the anterior cranial fossa.
2. The parietal bones are two large, rectangular bones on the superior and lateral
aspects of the skull, which form the majority of the cranial vault.
a. The four largest sutures of the skull are located where the parietal bones
articulate with other bones: the coronal, sagittal, lambdoid, and squamous
3. The occipital bone articulates with the parietal, temporal, and sphenoid bones,
forming most of the posterior wall and base of the skull.
a. The foramen magnum, a large opening through which the brain connects to
the spinal cord, is located in the base of the occipital bone.
4. The temporal bones articulate with the parietal bones and form the
inferolateral aspects of the skull and parts of the cranial floor.
a. The temporal bone is characterized by the mandibular fossa, which forms
part of the temporomandibular joint, and the external auditory meatus and
petrous, which house the ear.
5. The sphenoid bone spans the width of the middle cranial fossa, and articulates
with all other cranial bones.
6. The ethmoid bone lies between the sphenoid and nasal bones, and forms most
of the bony area between the nasal cavity and the orbits.