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Chiasmatic Groove
The chiasmatic groove (chiasmatic sulcus, optic groove, prechiasmatic sulcus) is a transverse groove upon the superior aspect of the body of sphenoid bone within the middle cranial fossa. It is bounded anteriorly by the sphenoidal limbus (a variably prominent ridge also representing the posterior boundary of the sphenoidal jugum), and posteriorly by the tuberculum sellae. The opening of each optic canal is placed at either lateral end of the chiasmatic sulcus. The optic chiasm In neuroanatomy, the optic chiasm, or optic chiasma (; , ), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, ... is situated superior and quite posterior to the chiasmatic groove (and not against the groove as the name suggests). References External links * * (#7) Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Of Sphenoid Bone
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. Superior surface The superior surface of the body ig. 1presents in front a prominent spine, the ethmoidal spine, for articulation with the cribriform plate of the ethmoid bone; behind this is a smooth surface slightly raised in the middle line, and grooved on either side for the olfactory lobes of the brain. This surface is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the prechiasmatic groove, above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery into the orbital cavity. Behind the chiasmatic groove is an elevation, the tuberculum sellae; and behind this is a deep depression, the saddle-shaped sella turcica (Turkish seat), the deepe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cranial Fossa
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. It is bounded in front by the posterior margins of the lesser wings of the sphenoid bone, the anterior clinoid processes, and the ridge forming the anterior margin of the chiasmatic groove; behind, by the superior angles of the petrous portions of the temporal bones and the dorsum sellae; laterally by the temporal squamae, sphenoidal angles of the parietals, and greater wings of the sphenoid. It is traversed by the squamosal, sphenoparietal, sphenosquamosal, and sphenopetrosal sutures. Anatomy Features Middle part The middle part of the fossa presents, in front, the chiasmatic groove and tuberculum sellae; the chiasmatic groove ends o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenoidal Limbus
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, bat or wasp with its wings extended. The name presumably originates from this shape, since () means in Ancient Greek. Structure It is divided into the following parts: * a median portion, known as the body of sphenoid bone, containing the sella turcica, which houses the pituitary gland as well as the paired paranasal sinuses, the sphenoidal sinuses * two greater wings on the lateral side of the body and two lesser wings from the anterior side. * Pterygoid processes of the sphenoides, directed downwards from the junction of the body and the greater wings. Two sphenoidal conchae are situated at the anterior and inferior part of the body. Intrinsic ligaments of the sphenoid T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberculum Sellae
The tuberculum sellae (or the tubercle of the sella turcica) is a slight median elevation upon the superior aspect of the body of sphenoid bone (that forms the floor of the middle cranial fossa) at the anterior boundary of the sella turcica ( hypophyseal (pituitary) fossa) and posterior boundary of the chiasmatic groove. A middle clinoid process The middle clinoid process is a small, bilaterally paired elevation on either side of the tuberculum sellae, at the anterior boundary of the sella turcica. A (larger) anterior clinoid process is situated lateral to each middle clinoid process. ... flanks the tuberculum sellae on either side. Additional images File:Slide1iiii.JPG, Tuberculum sellae References External links * Diagram at uni-mainz.de Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Foramen
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 superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery (with accompanying sympathetic nerve fibres) into the orbital cavity. Compared to the optic nerve, the ophthalmic artery is located inferolaterally within the canal. The left and right optic canals are 25mm apart posteriorly and 30mm apart anteriorly. The canals themselves are funnel-shaped (narrowest anteriorly). Additional images File:Orbital_bones.png, The seven bones which articulate to form the orbit. File:Gray145.png, Sphenoid bone The spheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Chiasm
In neuroanatomy, the optic chiasm, or optic chiasma (; , ), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes), it is located within the brain. This article is about the optic chiasm of vertebrates, which is the best known nerve chiasm, but not every chiasm denotes a crossing of the body midline (e.g., in some invertebrates, see Chiasm (anatomy)). A midline crossing of nerves inside the brain is called a decussation (see Definition of types of crossings). Structure In all vertebrates, the optic nerves of the left and the right eye meet in the body midline, ventral to the brain. In many vertebrates the left optic nerve crosses over the right one without fusing with it. In vertebrates with a large overlap of the visual fields of the two eyes, i.e., most mammals and birds, but also amphibians, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiasmatic Groove
The chiasmatic groove (chiasmatic sulcus, optic groove, prechiasmatic sulcus) is a transverse groove upon the superior aspect of the body of sphenoid bone within the middle cranial fossa. It is bounded anteriorly by the sphenoidal limbus (a variably prominent ridge also representing the posterior boundary of the sphenoidal jugum), and posteriorly by the tuberculum sellae. The opening of each optic canal is placed at either lateral end of the chiasmatic sulcus. The optic chiasm In neuroanatomy, the optic chiasm, or optic chiasma (; , ), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, ... is situated superior and quite posterior to the chiasmatic groove (and not against the groove as the name suggests). References External links * * (#7) Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
