optic chiasma


Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to optic chiasma: corpus callosum, optic tract

optic chiasma

n.
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.

op′tic chias′ma

(or chi′asm),


n.
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:
Noun1.optic chiasma - the crossing of the optic nerves from the two eyes at the base of the brain
chiasm, chiasma, decussation - an intersection or crossing of two tracts in the form of the letter X
References in periodicals archive ?
Especially if they did not have prior surgical or radiation therapy, the tumour is invasive or is abutting the optic chiasma.
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.
The subchiasmal growth of meningiomas may cause compression, elevation and dislocation of optic nerves and optic chiasma, which lead to visual function deterioration [3-6].
Suprasellar extension displacing and compressing the optic chiasma, 5 cases were showing "figure of 8" appearance and 8 cases with cavernous sinus invasion.
Computed tomography and MRI of the head showed no abnormality of brain parenchyma, ventricles, vasculature, optic chiasma or other cranial nerves.
It was causing suprasellar extension and abutment of optic chiasma.
Gadolinium contrast enhanced MRI revealed the three masses of CT scan to be single mass involving the optic nerves, optic chiasma and extending along optic tract on both sides.