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The Collaborative International Dictionary
Commissure

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.

  2. (Anat. & Zo["o]l.)

    1. The point of union between two parts, as the angles of the lips or eyelids, the mandibles of a bird, etc.

    2. A collection of fibers connecting parts of the brain or spinal marrow; a chiasma.

  3. (Bot.) The line of junction or cohering face of two carpels, as in the parsnip, caraway, etc.

Wiktionary
commissure

n. the place where two things are joined, especially the line where two parts of an anatomical structure join

Wikipedia
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, or alternately, to the full-length apposition of the closed mandibles, from the corners of the mouth to the tip of the beak.
  • It may refer to the upper and lower eyelids.
  • In female genitalia, the joining points of the two folds of the labia majora create two commissures - the anterior commissure just anterior to the prepuce of the clitoris, and the posterior commissure of the labia majora, directly posterior to the frenulum 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.

Usage examples of "commissure".

In fact, the ganglionic corpuscles of each eye may be considered as constituting a little brain, connected with the masses behind by the commissure, commonly called the optic nerve.

In addition to the corpus callosum there is another neural cabling between the left and right hemispheres, which is called the anterior commissure.

In human split-brain experiments in which the corpus callosum is cut, but not the anterior commissure, olfactory information is invariably transferred between the hemispheres.

Occasional transfer of some visual and auditory information through the anterior commissure also seems to occur, but un-predictably from patient to patient.

I noticed the thing-a growth smaller than a pea-near the left commissure when I was giving our beagle an illicit chocolate biscuit.

Our brains all have two hemispheres connected by the corpus callosum or great commissure.