The Temporal Bones

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The temporal bone is another paired cranial bone which is difficult to describe due to its various features, and projections. It consists of two major portions, the squamous portion, which is flat or fan-like and projects superiorly from the other, very thick and rugged portion, the petrosal portion.

The squamous portion assists in forming the squamous suture which separates the temporal bone from the adjacent and partially underlaying parietal bone. The petrosal portion contains the cavity of the middle ear and all the ear ossicles; the malleus, incas and stapes. This portion projects anterior and medialy beneath the skull. Projecting inferiorly from the petrosal portion is the slender styloid process which is of variable length. The styloid process serves as a muscle attachment for various thin muscles to the tongue and other structures in the throat. Externaly the petrosal portion possesses the external auditory meatus while internally there is an internal auditory meatus. Anterior to the external meatus the zygomatic process has its origin. This process projects forward toward the face and its articulation with the temporal process of the zygomatic. Just anterior of the external meatus and inferior of the origin of the zygomatic process is the glenoid or mandibular fossa which assists in forming the shallow socket of the tempro-mandibular joint. Posterior to the external auditory meatus is the inferiorly projecting mastoid process which serves as an attachment for the sternocleidomasotid muscle. Above the mastoid process is the supramastoid crest to which the posterior portion of the temporal muscle is attached.

The temporals touch, or articulate with, the following bones:

• Occipital
• Sphenoid
• Parietals
• Zygomatics
• Mandible