Temporal Bone Markings.
The temporal bone (os temporale; L., the temple) forms portions of the sides and base of the skull.
It is anatomically divided into four regions called the squamous, mastoid, temporal, and petrous parts.
The flattened squamous part forms the superior region of the bone that helps protect the sides of the brain (temporal lobe).
The thick, mastoid part forms the lower, posterior portion of the bone. Its roughened surface provides attachment sites for muscles that move the head and control the swallowing process.
The tympanic part lies anterior to the mastoid part and inferior to squamous part. It contains the external auditory meatus, a canal that leads to the tympanic membrane (eardrum) and bones of the middle ear.
The petrous part is a medial extension that forms the base of the skull between the sphenoid and occipital bones. It contains canals and receptors (inner ear) for the hearing and equilibrium systems.
a. Squamous part or squama (pars squamosa: squama temporalis) is the smooth, thin, superior portion of the bone that forms the lower lateral cranial wall. It gives attachment to the temporalis muscle.
b. Zygomatic process (processus zygomaticus temporalis) is a narrow, anterior extension from the inferior portion of the temporal squama. It joins with the temporal process of the zygomatic bone to form the zygomatic arch (or check bone). The zgomatic arch gives attachment to one of the chewing muscles, the maseter muscle.
c. Tympanic part (pars tympanica temporalis) is the region of the temporal bone that surrounds the ear canal. It is located inferior to squamous part and anterior to the mastoid part of the bone.
d. External acoustic (auditory) meatus (meatus acusticus externus temporalis) is a prominent canal (the ear canal) in the tympanic part of the temporal bone. It transmits sounds to the tympanic membrane (eardrum) in the middle ear.
e. Styloid Process (processus styloideus temporalis) is a narrow inferior extension from the bottom surface of the tympanic part of the temporal bone. It is an attachment point for two ligaments and three muscles that move the pharynx and larynx during the swallowig process.