chiasm


chiasm
1. An intersection or crossing of two lines. 2. [TA] In anatomy, a decussation or crossing of two fibrous bundles, such as tendins, nerves, or tracts. 3. In cytogenetics, the site at which two homologous chromosomes make contact (thus appearing to be crossed), enabling the exchange of genetic material during the prophase stage of meiosis. SYN: chiasma [TA]. [G. chiasma]
- Camper c. SYN: tendinous c. of the digital tendons.
- optic c. [TA] a flattened quadrangular body in front of the tuber cinereum and infundibulum, the point of crossing or decussation of the axons of the optic nerves; axons from the nasal retina cross to the opposite side while axons from the temporal retina run directly caudal without crossing, some pass transversely on the posterior surface between the two optic tracts and others pass transversely on the anterior surface between the two optic nerves. SYN: chiasma opticum [TA], optic decussation.
- tendinous c. of the digital tendons [TA] crossing of the tendons, the passage of the tendons of the flexor digitorum profundus (flexor digitorum longus in the foot) through the interval left by the decussation of the fibers of the tendons of the flexor digitorum superficialis (flexor digitorum brevis in the foot). SYN: chiasma tendinum [TA], Camper c..

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chi·asm 'kī-.az-əm, 'kē- n CHIASMA (1)

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chi·asm (kiґaz-əm) [L., Gr. chiasma] a decussation or X-shaped crossing; see chiasma.

Medical dictionary. 2011.

Look at other dictionaries:

  • chiasm — CHIÁSM, chiasme, s.n. Figură de stil care constă în reluarea, în ordine inversă, a două cuvinte sau expresii. – Din fr. chiasme. Trimis de valeriu, 03.03.2003. Sursa: DEX 98  chiásm (figură de stil) s. n., pl. chiásme Trimis de siveco,… …   Dicționar Român

  • Chiasm — may refer to: Chiasm (musical project), an electronic music project by Emileigh Rohn Optic chiasm, the part of the brain where the optic nerves partially cross Chiasma (genetics), the point where two chromatids are intertwined (interwoven) in a… …   Wikipedia

  • Chiasm — Chi asm (k[imac] [a^]z m), ||Chiasma Chi*as ma (k[ i]*[a^]z m[.a]), n. [NL. chiasma, fr. Gr. chi asma two lines placed crosswise, fr. ? to mark with a [chi].] (Anat.) A commissure; an intersection or crossing of two tracts; especially, the optic… …   The Collaborative International Dictionary of English

  • chiasm — [kī′az΄əm] n. 1. CHIASMA (n. 1 & 2) 2. CHIASMUS * * * …   Universalium

  • chiasm — anglicized form of CHIASMUS (Cf. chiasmus) …   Etymology dictionary

  • chiasm — [kī′az΄əm] n. 1. CHIASMA (n. 1 & 2) 2. CHIASMUS …   English World dictionary

  • Chiasm — Emileigh Rohn ist eine Musikerin aus Detroit im US Bundesstaat Michigan. Ihre CDs werden von COP International vertrieben. Sie ist Betreiberin des von ihr 1998 gegründeten Elektronik Musikprojekts Chiasm. Der Projektname (von griechisch χίασμα,… …   Deutsch Wikipedia

  • chiasm — noun an intersection or crossing of two tracts in the form of the letter X • Syn: ↑chiasma, ↑decussation • Derivationally related forms: ↑decussate (for: ↑decussation), ↑chiasmal, ↑chiasmic, ↑ …   Useful english dictionary

  • chiasm — noun Etymology: New Latin chiasma Date: 1870 chiasma 1 …   New Collegiate Dictionary

  • chiasm — n. crossing, intersecting, point of intersection (Genetics, Anatomy) …   English contemporary dictionary


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