Superior view

Superior view

FIGURE 7.11 Floor of the Cranial Cavity

The roof of the skull has been removed, and the floor is seen from a superior view. (The names of the bones are in bold.)

Two long, pointed styloid (st ī ′loyd; stylus- or pen-shaped) processes project from the floor of the temporal bone (seefigures 7.4 and 7.12). Three muscles involved in moving thetongue, hyoid bone, and pharynx attach to each process. The mandibular fossa, where the mandible articulates with the restof the skull, is anterior to the mastoid process at the base of thezygomatic arch.The posterior opening of the nasal cavity is bounded on eachside by the vertical bony plates of the sphenoid bone: the medialpterygoid (ter′i-goyd; wing-shaped) plate and the lateralpterygoid plate. The medial and lateral pterygoid muscles, whichhelp move the mandible, attach to the lateral plate (see chapter 10).The vomer forms most of the posterior portion of the nasal sep-tum and can be seen between the medial pterygoid plates in thecenter of the nasal cavity.The hard palate, or bony palate, forms the majority of thefloor of the nasal cavity (and the roof of the mouth). Sutures joinfour bones to form the hard palate: The palatine processes of thetwo maxillary bones form the anterior two-thirds of the hard pal-ate, and the horizontal plates of the two palatine bones form theposterior one-third of the hard palate. The tissues of the soft palateextend posteriorly from the hard palate. The hard and soft palatesseparate the nasal cavity from the mouth, enabling humans tochew and breathe at the same time.

Individual Bones of the Skull

The skull, or cranium, is composed of 22 separate bones (table 7.7;see table 7.1). In addition, the skull contains six inner ear bones,

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