Commissure

Commissure

A commissure is the place where two things are joined. The term is used especially in the fields of anatomy and biology.

In anatomy, commissure refers to a bundle of nerve fibers that cross the midline at their level of origin or entry (as opposed to a decussation of fibers that cross obliquely).

  • The most common usage of the term refers to the brain's commissures, of which there are five—the anterior commissure, posterior commissure, corpus callosum, hippocampal commissure (commissure of fornix), and habenular commissure—and which consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord is found the anterior white commissure.
  • Commissure may also refer to cardiac anatomy of heart valves. In the heart, a commissure is the area where two valve leaflets have abnormally come together.
  • The term may also refer to the junction of the upper and lower lips (see labial commissure of mouth).
  • It may refer to the junction of the upper and lower mandibles of a bird's beak,[1] or alternately, to the full-length apposition of the closed mandibles, from the corners of the mouth to the tip of the beak.[2]
  • It may refer to the upper and lower eyelids.
  • In female genitalia, the joining points of the two folds of the labia major create two commissures - the anterior commissure just anterior to the prepuse of the clitoris, and the posterior commissure of the labia majora, directly posterior to the fenulum of the labia minora and anterior to the perineal raphe.

In biology, the meeting of the two valves of a brachiopod or clam is a commissure; in botany, the term is used to denote the place where a fern's laterally expanded vein endings come together in a continuous marginal sorus.

See also

References

  1. ^ Coues, Elliott (1890). Handbook of Field and General Ornithology. London: Macmillan and Co. p. 155. OCLC 263166207. http://books.google.com/?id=yU8aAAAAYAAJ&pg=PA1&lpg=PA1&dq=Handbook+of+Field+and+General+Ornithology#v=onepage&q&f=false. 
  2. ^ Campbell, Bruce; Lack, Elizabeth, eds (1985). A Dictionary of Birds. Carlton, England: T and A D Poyser. p. 105. ISBN 0-85661-039-9. 

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  • commissure — [ kɔmisyr ] n. f. • 1314; lat. commissura, de committere « joindre ensemble » 1 ♦ Anat. Point de jonction de deux parties. Commissure blanche, grise de la moelle. Commissures du cerveau. Adj. COMMISSURAL, ALE, AUX . 2 ♦ Cour. Commissures (des… …   Encyclopédie Universelle

  • commissure — COMMISSURE. sub. fém. Terme didactique, qui se dit Du point d union de quelques parties du corps humain. La commissure des nerfs optiques. La commissure des lèvres …   Dictionnaire de l'Académie Française 1798

  • Commissure — Com*mis sure (? or ?; 134 6), n. [L. commissura a joining together: cf. F. commissure. See {Commit}.] 1. A joint, seam, or closure; the place where two bodies, or parts of a body, meet and unite; an interstice, cleft, or juncture. [1913 Webster]… …   The Collaborative International Dictionary of English

  • commissure — [käm′ə shoor΄] n. [ME & OFr < L commissura < commissus, pp. of committere: see COMMIT] 1. a line where two parts join or unite; joint; seam 2. Anat. the area where symmetrical parts join, as of the lips or of the brain s hemispheres… …   English World dictionary

  • commissure — 1. Angle or corner of the eye, lips, or labia. 2. A bundle of nerve fibers passing from one side to the other in the brain or spinal cord. SYN: commissura [TA]. anterior c. [TA] a round bundle of …   Medical dictionary

  • COMMISSURE — s. f. T. d Anat., qui se dit Du point d union de quelques parties du corps. La commissure des nerfs optiques. La commissure des lèvres, des paupières …   Dictionnaire de l'Academie Francaise, 7eme edition (1835)

  • COMMISSURE — n. f. Point de jonction de deux ou plusieurs parties. En termes d’Anatomie. La commissure des nerfs optiques, La commissure des lèvres, des paupières. En termes d’Architecture, Les commissures d’un pilier …   Dictionnaire de l'Academie Francaise, 8eme edition (1935)

  • Commissure — En anatomie, une commissure est un moyen d union entre deux parties, par exemple la commissure du cerveau ou des lèvres. Lien interne Corps calleux Portail de la médecine Catégorie : Vo …   Wikipédia en Français

  • commissure — (ko mi ssu r ) s. f. 1°   Terme d anatomie. Point de jonction de certaines parties. La commissure des lèvres. 2°   Terme d architecture. Joint des pierres. Des ornements propres à cacher les commissures des colonnes. 3°   Terme de musique. S est… …   Dictionnaire de la Langue Française d'Émile Littré

  • Commissure palpébrale — ● Commissure palpébrale synonyme de canthus …   Encyclopédie Universelle

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