optic chiasma

or optic chiasm

noun

1. 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.

Word History and Origins

Origin of optic chiasma¹

First recorded in 1870–75

Example Sentences

The anterior end of the fore-brain remains relatively small throughout life as the infundibulum, and the junction of this part of the fore-brain with the part which is so largely developed, as the rudiment of the cerebrum, is marked by the attachment of the optic chiasma.

From Project Gutenberg

It raced inward along the nerve trunk, split at the optic chiasma, and entered the corpora quadrigemina where it branched into innumerable microscopic filaments that followed the main neural paths of the man's brain, probing the major areas of thought and reflex.

From Project Gutenberg

From their position close to the back of the optic chiasma these growths affect the fibres passing to the nasal half of each retina, and so give rise to bilateral temporal hemianopsia, and although there is no choked disc, the optic nerves undergo primary atrophy from pressure, and there is failure of sight.

From Project Gutenberg

Operative treatment has been successful in a number of cases, but as the anterior lobe is essential to life, the operation is merely directed towards the relief of pressure on the optic chiasma with a view to preventing loss of vision.

From Project Gutenberg

Pressure on the optic chiasma, for example by a tumour of the pituitary body, is associated with bilateral temporal hemianopsia.

From Project Gutenberg