The temporal bone

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The cranium includes all the bones of the head. Altogether, there are 26 cranial bones plus the mandible. Except for the mandible, these bones mostly are fused together so that they do not move. The joints between most of the cranial bones are borders where the bones knit together, called sutures.

The left and right temporal bones are on the sides of the cranium. Each of them consists of several parts. The squamous portion of the bone extends upward to make up part of the cranial wall surrounding the brain. Projecting medially from the base of the temporal bone is the petrous portion. When writing out the name of the temporal bones, you should always include the side (right or left) as part of the name.

There are several obvious features of each temporal bone. The bony opening for the ear is called the external auditory meatus. Behind the ear is a thick, bony projection called the mastoid process. A thin, slender projection under the temporal bone is called the styloid process, but this is often broken or not ossified in its connection to the bone. A projection of the temporal bone makes up the posterior half of a structure called the zygomatic arch as well.

The temporal bone

Each of the temporal bones normally touches, or articulates with five bones visible on the outside of the skull. Can you name them?