optic chiasma

A structure in the brain formed by the partial intersection or crossing of the optic nerve fibers on the underside of the hypothalamus. Also called optic chiasm.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

op′tic chias′ma

(or chi′asm),

a site at the base of the forebrain where the inner half of the fibers of the left and right optic nerves cross to the opposite side of the brain.

[1870–75]

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun

optic chiasma - the crossing of the optic nerves from the two eyes at the base of the brain

chiasma opticum, optic chiasm

chiasm, chiasma, decussation - an intersection or crossing of two tracts in the form of the letter X

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References in periodicals archive

Caption: Figure 3: (a) T2 weighted image showing bilaterally oedematous optic nerves and optic chiasma with (b) patchy enhancement of the optic chiasma on T1 weighted image.

The Prevalence of Anti-Aquaporin 4 Antibody in Patients with Idiopathic Inflammatory Demyelinating Diseases Presented to a Tertiary Hospital in Malaysia: Presentation and Prognosis

Especially if they did not have prior surgical or radiation therapy, the tumour is invasive or is abutting the optic chiasma.

Preconception management of endocrine disorders

In this article, we present a patient who presented with fever, vomiting and sudden loss of vision and limited outward gaze in the left eye following trauma and who was found to have pituitary macroadenoma causing compression of the optic chiasma and optic nerve on the left side on cranial and pituitary magnetic resonance imaging.

A pediatric case of pituitary macroadenoma presenting with pituitary apoplexy and cranial nerve involvement: case report

Suprasellar extension displacing and compressing the optic chiasma, 5 cases were showing "figure of 8" appearance and 8 cases with cavernous sinus invasion.

Multiplanar MRI and CT imaging of sellar and parasellar tumours with clinical and pathological correlation

In mammals, the suprachiasmatic nucleus (SCN), located right above the optic chiasma (where two optic nerves from the eye criss-cross) in the hypothalamus section of our brain, functions as the master circadian clock.

Circadian Lighting for Health

Computed tomography and MRI of the head showed no abnormality of brain parenchyma, ventricles, vasculature, optic chiasma or other cranial nerves.

Optic nerve involvement in a borderline lepromatous leprosy patient on multidrug therapy