[The arterial irrigation of the optic chiasma]

The purpose of this study was to determine the distribution of the arterial branches that are supplying the optic chiasma. This study was carried out on 40 cerebral hemispheres fixed in formaldehid and dissected under a surgical microscope; 12 of them were at first injected with colored nitrolac. It was observed the origin, traject and distribution of the arterial branches which supply the optic chiasma. The arteries are branches from the anterior cerebral artery (100%); internal carotid artery (90%); anterior communicating artery (70%); posterior communicating artery (40%); anterior choroidal artery (5%). Some of this branches pass directly into the chiasma, others form a superficial, pial network, well represented on the inferior surface and posterior border of the optic chiasma. The data obtained add new aspects to a systematic description of the arterial branches distributed to the chiasma. The knowledge of the blood supply of the optic chiasma, in relationship with the somatopy of the optic fibers allow to understand some hemianopic visual field defects in different neuro-ophthalmologic syndromes.