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## Cranial Fossae The contoured floor of the cranial cavity exhibits three curved depressions called the cranial fossae. * **Anterior cranial fossa:** The shallowest of the three depressions. It is formed by the frontal bone, the ethmoid bone, and the lesser wings of the sphenoid bone. The anterio...

## Cranial Fossae The contoured floor of the cranial cavity exhibits three curved depressions called the cranial fossae. * **Anterior cranial fossa:** The shallowest of the three depressions. It is formed by the frontal bone, the ethmoid bone, and the lesser wings of the sphenoid bone. The anterior cranial fossa houses the frontal lobes of the brain. * **Middle cranial fossa:** Inferior and posterior to the anterior cranial fossa. It ranges from the posterior edge of the lesser wings of the sphenoid bone (anteriorly) to the anterior region of the petrous part of the temporal bone (posteriorly). It houses the temporal lobes of the brain and the pituitary gland. * **Posterior cranial fossa:** The most inferior and posterior cranial fossa and extends from the posterior region of the petrous part of the temporal bones to the occipital bone. This fossa supports part of the brainstem and the cerebellum. ## Sutures * Sutures are immovable fibrous joints that form the boundaries between the cranial bones. * Dense regular connective tissue connects cranial bones firmly together at a suture. * The sutures often have intricate, interlocking forms resembling puzzle pieces. * Numerous sutures are present in the skull, each with a specific name. * Many of the smaller sutures are named for the bones or features they interconnect. For example, the occipitonasal suture connects the occipital bone with the portion of the temporal bone that houses the mastoid process.