Its anterior (front) surface forms the rear portion of the middle fossa (a cavity) in the base of the skull. The latter form the carotid canal, which allows important arteries to access the brain. Moving upward, this portion has a base fused with the squama and mastoid portion, and an apex that sits between the occipital and sphenoid bones. Petrous Part: Also known as the “pyramid part,” because of its shape, the petrous part sits at the base of the skull at between the occipital (the part that represents the base) and sphenoid bones (the portion just beneath the temples). ![]() The upper part of this portion has been observed to be hollow in places, but these openings grow smaller as you move down. ![]() Moving downward, this portion becomes a conical projection-the mastoid process-which connects to muscles essential for head movement. This portion is perforated and includes the mastoid foramen, an opening that allows a vein to access the transverse sinus (the area on each side of the head that drains blood from the back of the head) as well as an artery that provides oxygenated blood to the layer of tissue tasked with protecting the brain (dura mater). Mastoid Part: Forming the rear part of the temporal bone, the mastoid part’s outer surface is rough and attaches to muscles that regulate the motion of eyebrows (occipitalis muscle) as well as those above the ear (superior auricular muscle).In addition, this part of the temporal bone is connected to ligaments regulating muscles in the upper portion of the mandible, or jawbone. The bottom end of this bone connects to the masseter, another major muscle for chewing. ![]() The front end of the squama is serrated and connects with the zygomatic bone-one of two paired bones that form the cheeks and the sidewalls of the orbits (the openings where the eyeballs sit).
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