Chiasmatic groove | |
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Details | |
Identifiers | |
Latin | sulcus praechiasmaticus, sulcus chiasmaticus |
TA98 | A02.1.05.005 |
TA2 | 588 |
FMA | 75760 |
Anatomical terms of bone |
The chiasmatic groove (chiasmatic sulcus, optic groove, prechiasmatic sulcus) is a transverse [1] groove upon the superior aspect of the body of sphenoid bone [1] [2] : 509 within the middle cranial fossa. [2] : 508-509 It is bounded anteriorly by the sphenoidal limbus (a variably prominent ridge also representing the posterior boundary of the sphenoidal jugum [3] ), and posteriorly by the tuberculum sellae. [1] The opening of each optic canal is placed at either lateral end of the chiasmatic sulcus. The optic chiasm is situated superior and quite posterior to the chiasmatic groove (and not against the groove as the name suggests). [2] : 509
The pons is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum.
The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation. The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.
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 parietal bones are two bones in the skull which, when joined 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 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 biological morphology and anatomy, a sulcus is a furrow or fissure. It may be a groove, natural division, deep furrow, elongated cleft, or tear in the surface of a limb or an organ, most notably on the surface of the brain, but also in the lungs, certain muscles, as well as in bones, and elsewhere. Many sulci are the product of a surface fold or junction, such as in the gums, where they fold around the neck of the tooth.
The sphenoid sinus is a paired paranasal sinus occurring within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses. The pair of sphenoid sinuses are separated in the middle by a septum of sphenoid sinuses. Each sphenoid sinus communicates with the nasal cavity via the opening of sphenoidal sinus. The two sphenoid sinuses vary in size and shape, and are usually asymmetrical.
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 optic foramen is the opening to the optic canal. The canal is located in the sphenoid bone; it is bounded medially by the body of the sphenoid and laterally by the lesser wing of the sphenoid.
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 tuberculum sellae is a slight median elevation upon the superior aspect of the body of sphenoid bone at the anterior boundary of the sella turcica and posterior boundary of the chiasmatic groove. A middle clinoid process flanks the tuberculum sellae on either side.
The interpeduncular fossa is a deep depression of the ventral surface of the midbrain between the two crura cerebri.
The anterior interventricular sulcus is one of two grooves separating the ventricles of the heart. They can also be known as paraconal interventricular groove or subsinosal interventricular groove respectively. It is situated on the sternocostal surface of the heart, close to the left margin of the heart. It extends between the coronary sulcus, and the apex of the heart; upon reaching the diaphragmatic surface of the heart, it ends at the notch of cardiac apex. It contains the anterior interventricular branch of the left coronary artery, and great cardiac vein.
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 interpeduncular cistern is the subarachnoid cistern situated between the dorsum sellae (anteriorly) and the two cerebral peduncles of the mesencephalon (midbrain). Its roof is represented by the floor of the third ventricle. Its floor is formed by the arachnoid membrane extending between the temporal lobes of either side. Anteriorly, it extends to the optic chiasm.
The chiasmatic cistern or suprasellar cistern is a small subarachnoid cistern related to the optic chiasm.
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.
This article describes anatomical terminology that is used to describe the central and peripheral nervous systems - including the brain, brainstem, spinal cord, and nerves.
The arcuate eminence is a rounded prominence upon the superior surface of the petrous part of the temporal bone forming the lateral part of the posterior wall of the middle cranial fossa. The arcuate eminence indicates the position of the underlying superior semicircular canal.