| Skull base | |
|---|---|
 Base of the skull, inferior or inner surface | |
 Base of the skull, exterior or outer surface. Showing various muscle attachments. | |
| Details | |
| Identifiers | |
| Latin | basis cranii externa et. interna |
| MeSH | D019291 |
| TA98 | A02.1.00.044 |
| TA2 | 447 |
| FMA | 52801 |
| Anatomical terms of bone | |
The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria.
Structures found at the base of the skull are for example:
There are five bones that make up the base of the skull:
Articles related to anatomy include:
The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit. Its shape somewhat resembles that of a butterfly or bat with its wings extended.
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 the 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 at a fibrous joint known as a cranial suture, form the sides and roof of the neurocranium. 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 an artery in the neck which supplies the anterior and middle cerebral circulation.
The sella turcica is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, gorillas and orangutans. It serves as a cephalometric landmark. The pituitary gland or hypophysis is located within the most inferior aspect of the sella turcica, the hypophyseal fossa.
In mammalian anatomy, the cribriform plate, horizontal lamina or lamina cribrosa is part of the ethmoid bone. It is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities. It supports the olfactory bulb, and is perforated by olfactory foramina for the passage of the olfactory nerves to the roof of the nasal cavity to convey smell to the brain. The foramina at the medial part of the groove allow the passage of the nerves to the upper part of the nasal septum while the foramina at the lateral part transmit the nerves to the superior nasal concha.
The posterior cranial fossa is the part of the cranial cavity located between the foramen magnum, and tentorium cerebelli. It is formed by the sphenoid bones, temporal bones, and occipital bone. It lodges the cerebellum, and parts of the brainstem.
A jugular foramen is one of the two large foramina (openings) in the base of the skull, located behind the carotid canal. It is formed by the temporal bone and the occipital bone. It allows many structures to pass, including the inferior petrosal sinus, three cranial nerves, the sigmoid sinus, and meningeal arteries.
The greater wing of the sphenoid bone, or alisphenoid, is a bony process of the sphenoid bone, positioned in the skull behind each eye. There is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally, and backward.
The carotid canal is a passage in the petrous part of the temporal bone of the skull through which the internal carotid artery and its internal carotid (nervous) plexus pass from the neck into the cranial cavity.
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles and it has openings for 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. In other mammals, it is a separate bone, the petrosal bone.
The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the condyles for articulation with the superior facets of the atlas.
The middle cranial fossa is formed by the sphenoid bones, and the temporal bones. It lodges the temporal lobes, and the pituitary gland. It is deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior cranial fossa by the clivus and the petrous crest.
The anterior cranial fossa is a depression in the floor of the cranial base which houses the projecting frontal lobes of the brain. It is formed by the orbital plates of the frontal, the cribriform plate of the ethmoid, and the small wings and front part of the body of the sphenoid; it is limited behind by the posterior borders of the small wings of the sphenoid and by the anterior margin of the chiasmatic groove. The lesser wings of the sphenoid separate the anterior and middle fossae.
The perpendicular plate of palatine bone is the vertical part of the palatine bone, and is thin, of an oblong form, and presents two surfaces and four borders.
The body of the sphenoid bone, more or less cubical in shape, is hollowed out in its interior to form two large cavities, the sphenoidal sinuses, which are separated from each other by a septum.
The following outline is provided as an overview of and topical guide to human anatomy:
