Search results
Results from the WOW.Com Content Network
The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes), it is located within the brain. [2] [3] 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)).
The optic tract is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus. [14] The optic tract represents the first stage in the visual pathway in which visual information is transferred in a homonymous nature. [15]
Clinically, no optic field deficits have been observed in a small series of optic nerve sections at the optic nerve-chiasm junction. [3] Several important structures are located adjacent to the optic chiasm. The supraclinoid branches of the internal carotid artery flank the chiasm. The cavernous sinuses are lateral and inferior to the chiasm.
Bitemporal hemianopsia is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary gland.
The optic recess – marks the inferior end of the lamina terminalis, with the optic chiasm forming the immediately adjacent floor. The portion of the floor immediately posterior of the optic chiasm distends inferiorly, and slightly anteriorly, to form a funnel (the infundibulum); the recess leading to the funnel is known as the infundibular ...
Optic gliomas are usually pilocytic tumors, and can involve the optic nerve or optic chiasm. [3] Optic gliomas are usually associated with neurofibromatosis type 1 in 30% of people with the condition. [3] Optic nerve gliomas have low mortality but extremely high prevalence of vision loss and eye-bulging exophthalmos) in children. [4]
Aneurysms of the anterior communicating artery are the most common circle of Willis aneurysm [4] and can cause visual field defects such as bitemporal heteronymous hemianopsia (due to compression of the optic chiasm), [5] psychopathology and frontal lobe pathology. [6]
The tuber cinereum is a convex mass of grey matter, [3]: 495 a ventral/inferior distention of the hypothalamus forming the floor of the third ventricle. [citation needed] The portion of the tuber cinerum at the base of the infundibulum (pituitary stalk) is the median eminence; [2] the infundibulum extends ventrally/inferiorly from the median eminence to become continuous with the infundibulum.