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 (kī-ăz′mə) also chi·asm (kī′ăz′əm)
n. pl. chi·as·ma·ta (-mə-tə) or chi·as·mas also chi·asms
1. Anatomy A crossing or intersection of two tracts, as of nerves or ligaments.
2. Genetics The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over.

[Greek khīasma, cross-piece, from khīazein, to mark with an X, from khei, khī, chi (from the letter's shape).]

chi·as′mal, chi·as′mic, chi′as·mat′ic (-măt′ĭk) adj.


(kaɪˈæzmə) or


n, pl -mas, -mata (-mətə) or -asms
1. (Genetics) cytology the cross-shaped connection produced by the crossing over of pairing chromosomes during meiosis
2. (Anatomy) anatomy the crossing over of two parts or structures, such as the fibres of the optic nerves in the brain
[C19: from Greek khiasma wooden crosspiece, from khiazein to mark with an X, from khi chi1]
chiˈasmal, chiˈasmic adj


(kaɪˈæz mə)

also chi•asm

(ˈkaɪ æz əm)

n., pl. -as•mas, -as•ma•ta (-ˈæz mə tə) also -asms.
1. Anat. a crossing or decussation. Compare optic chiasma.
2. a point of overlap of paired chromatids at which fusion and exchange of genetic material take place during prophase of meiosis.
[1830–40; < Greek: crosspiece of wood, cross-bandage =chi chi + -asma n. suffix]
chi•as′mal, chi•as′mic, chi`as•mat′ic (-ˈmæt ɪk) adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.chiasma - an intersection or crossing of two tracts in the form of the letter X
anatomical structure, bodily structure, body structure, complex body part, structure - a particular complex anatomical part of a living thing; "he has good bone structure"
chiasma opticum, optic chiasm, optic chiasma - the crossing of the optic nerves from the two eyes at the base of the brain


, chiasma
n. quiasma.
1. cruzamiento de dos vías o conductos;
2. punto de cruzamiento de las fibras de los nervios ópticos.
References in periodicals archive ?
technology, Chiasma is evaluating additional proteins, peptides and small molecule drugs that are currently only available by injection, but could potentially be converted to oral delivery.
Companies Involved in acromegaly therapeutics development and mentioned in this pipeline review report include Aegis Therapeutics, LLC, Antisense Therapeutics Limited, Chiasma, Inc.
70 million Series E financing round has been gathered by Chiasma, Inc.
The hypothalamus is located at the base of the forebrain beneath the thalamus and posterior to the optic chiasma.
It was causing suprasellar extension and abutment of optic chiasma.
Linda Cummins, Debussy and the Fragment, Chiasma, 18 (New York: Amsterdam: Rodopi, 2006; originally presented as the author's Louisiana State University Ph.
At the same time, she found her spiritual home at the University's Business School, where she was inaugural chief executive of Spark, the student-led entrepreneurship Challenge, and the founder and first chief executive of Chiasma for enterprising science students and graduates.
Magnetic resonance imaging (MRI) of the sellar area revealed a large intrasellar mass with a dimension of 15x14x12mm that extended to the suprasellar cisterns, with thickening of the infundibular stalk and elevating optic chiasma.
Depth, which only appears when it is paired with given surfaces, points attention toward a chiasma of formless color and screen design.
In another study on neuroepithelial cells migration in mice subsequent poisoning with vincristine during pregnancy has been expressed that this drug can cause abnormalities in the cephalic fold and optic chiasma which is seen from blight to Asymmetric growth [17].
Chiasma is developing technology that could enable oral delivery of protein- and peptide-based drugs that are available only by injection or intravenous methods.
Optic nerve gliomas (ONGs) are seen in 5-15% of cases, can involve one or both optic nerves and commonly extend posteriorly to involve the chiasma (Fig.