optic chiasma

optic chiasma n the X-shaped partial decussation on the undersurface of the hypothalamus through which the optic nerves are continuous with the brain called also optic chiasm

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the X-shaped structure formed by the two optic nerves, which pass backwards from the eyeballs to meet in the midline beneath the brain, near the pituitary gland. Nerve fibres from the nasal side of the retina of each eye cross over to join fibres from the lateral side of the retina of the opposite eye. The optic tracts resulting from the junction pass backwards to the occipital lobes.

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chiasma opticum [TA] optic chiasm: the part of the hypothalamus formed by the decussation, or crossing, of the fibers of the optic nerve from the medial half of each retina; called also optic decussation.


Medical dictionary. 2011.

Look at other dictionaries:

  • optic chiasma — noun the crossing of the optic nerves from the two eyes at the base of the brain • Syn: ↑optic chiasm, ↑chiasma opticum • Hypernyms: ↑chiasma, ↑chiasm, ↑decussation …   Useful english dictionary

  • optic chiasma — noun Date: 1872 the X shaped partial decussation on the undersurface of the hypothalamus through which the optic nerves are continuous with the brain called also optic chiasm …   New Collegiate Dictionary

  • optic chiasma — 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. Also, optic chiasm. [1870 75] * * * …   Universalium

  • optic chiasma — op′tic chias′ma (or chi′asm) n. anat. 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 • Etymology: 1870–75 …   From formal English to slang

  • Перекрест Зрительный (Optic Chiasma) — Х образная структура, образованная двумя перекрещивающимися зрительными нервами, которые идут в направлении мозга. Перекрест расположен на нижней поверхности мозга вблизи гипофиза. Перекрещиваются лишь волокна, идущие от медиальной половины… …   Медицинские термины

  • optic tract — n the portion of each optic nerve between the optic chiasma and the diencephalon proper * * * tractus opticus …   Medical dictionary

  • optic chiasm — noun the crossing of the optic nerves from the two eyes at the base of the brain • Syn: ↑optic chiasma, ↑chiasma opticum • Hypernyms: ↑chiasma, ↑chiasm, ↑decussation * * * noun see optic chia …   Useful english dictionary

  • Optic chiasm — Brain: Optic chiasm Visual pathway with optic chiasm (X shape outlined, red) (1543 image from Andreas Vesalius Fabrica) Latin chiasma opticum Gray s …   Wikipedia

  • Optic nerve — The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. These impulses are dispatched through the optic nerve… …   Medical dictionary

  • Optic nerve pathways — The left and right branches of the optic nerves join behind the eyes, just in front of the pituitary gland, to form a cross shaped structure called the optic chiasma. Within the optic chiasma, some of the nerve fibers cross. The fibers from the… …   Medical dictionary

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