The occipital bone is a cranial dermal bone and the main bone of the occiput. It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord.
The parietal bones are two bones in the skull which, when joined together at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin paries (-ietis), wall.
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The internal carotid artery is located in the inner side of the neck in contrast to the external carotid artery. In human anatomy, they arise from the common carotid arteries where these bifurcate into the internal and external carotid arteries at cervical vertebral level 3 or 4; the internal carotid artery supplies the brain including eyes, while the external carotid nourishes other portions of the head, such as face, scalp, skull, and meninges.
The foramen lacerum is a triangular hole in the base of skull, located between the sphenoid, the apex of the petrous temporal and the basilar part of the occipital.
The posterior cranial fossa is part of the cranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum.
The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound.
The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.
The inferior petrosal sinuses are two small sinuses situated on the inferior border of the petrous part of the temporal bone, one on each side. Each inferior petrosal sinus drains the cavernous sinus into the internal jugular vein.
The jugular foramen is a large foramen (opening) in the base of the skull, located behind the carotid canal. It is formed in front by the petrous portion of the temporal bone, and behind by the occipital bone; it is generally larger on the right than on the left side.
The transverse sinuses, within the human head, are two areas beneath the brain which allow blood to drain from the back of the head. They run laterally in a groove along the interior surface of the occipital bone. They drain from the confluence of sinuses to the sigmoid sinuses, which ultimately connect to the internal jugular vein. See diagram : labeled under the brain as "SIN. TRANS.".
The occipital vein begins as a plexus at the posterior aspect of the scalp from the external occipital protuberance and superior nuchal line to the back part of the vertex of the skull.
The squamous part of temporal bone, or temporal squama, forms the front and upper part of the temporal bone, and is scale-like, thin, and translucent.
The mastoid part of the temporal bone is the back part of the temporal bone. Its rough surface gives attachment to various muscles and it has openings for the transmission of blood vessels. From its borders the mastoid part articulates with two other bones.
The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior, the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word petrosus, meaning "stone-like, hard". It is one of the densest bones in the body.
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal.
The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest.
The mastoid foramen is a hole in the posterior border of the temporal bone. It transmits a Mastoid emissary vein to the sigmoid sinus and a small branch of the occipital artery, the posterior meningeal artery to the dura mater.
The petrosquamous sinus, is a fetal vein that generally disappears by birth and, when present, runs backward along the junction of the squama and petrous portion of the temporal, and opens into the transverse sinus.
The calvaria is the top part of the skull. It is the upper part of the neurocranium and covers the cranial cavity containing the brain. It forms the main component of the skull roof.
