|
Chiasmatic Groove
The superior surface of the body 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, prechiasmatic sulcus), above and behind which lies the optic chiasma of cranial nerve 2 (the optic nerve). The groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery into the orbital cavity In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , .... References External links * * (#7) Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenoid Bone
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. 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 The more important of these are: * the pterygospinous, stretching between the spina angu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Chiasma
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 For the different types of optic chiasm, see 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 ... [...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 sphenoid bon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual information from the retina to the brain. In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells; it extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, pretectal nuclei, and superior colliculus. Structure The optic nerve has been classified as the second of twelve paired cranial nerves, but it is technically part of the central nervous system, rather than the peripheral nervous system because it is derived from an out-pouching of the diencephalon ( optic stalks) during embryonic development. As a consequence, the fibers of the optic nerve are covered with myelin produced by oligodendrocytes, rather than Schwann cells of the peripheral nervous system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmic Artery
The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some structures in the nose, face, and meninges. Occlusion of the ophthalmic artery or its branches can produce sight-threatening conditions. Structure The ophthalmic artery emerges from the internal carotid artery. This is usually just after the internal carotid artery emerges from the cavernous sinus. In some cases, the ophthalmic artery branches just before the internal carotid exits the cavernous sinus. The ophthalmic artery emerges along the medial side of the anterior clinoid process. It runs anteriorly, passing through the optic canal inferolaterally to the optic nerve. It can also pass superiorly to the optic nerve in a minority of cases. In the posterior third of the cone of the orbit, the ophthalmic artery turns sharply and mediall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Cavity
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of which the eye occupies . The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and duct, the eyelids, medial and lateral palpebral ligaments, cheek ligaments, the suspensory ligament, septum, ciliary ganglion and short ciliary nerves. Structure The orbits are conical or four-sided pyramidal cavities, which open into the midline of the face and point back into the head. Each consists of a base, an apex and four walls."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009 Openings There are two important foramina, or windows, two important f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiasmatic Groove
The superior surface of the body 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, prechiasmatic sulcus), above and behind which lies the optic chiasma of cranial nerve 2 (the optic nerve). The groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery into the orbital cavity In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , .... References External links * * (#7) Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
