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a narrow connection between two larger bodies or parts. adj., adj isth´mian.
isthmus of auditory tube (isthmus of eustachian tube) the narrowest part of the eustachian tube at the junction of its bony and cartilaginous parts.
isthmus of fauces (isthmus fau´cium) the constricted aperture between the cavity of the mouth and the pharynx.
isthmus of rhombencephalon the narrow segment of the fetal brain, forming the plane of separation between the rhombencephalon and cerebrum.
isthmus of thyroid the band of tissue joining the lobes of the thyroid.
isthmus of uterine tube the narrower, thicker-walled portion of the fallopian (uterine) tube closest to the uterus.
isthmus of uterus the constricted part of the uterus between the cervix and the body of the uterus.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
isth·mus·es(is'mŭs, -mī, -mŭs-ĕz), [TA]
1. A constriction in the embryonic neural tube delineating the anterior portion of the rhombencephalon, the future metencephalon, from the more rostrally located mesenephalon.
2. Synonym(s): rhombencephalic isthmus
Farlex Partner Medical Dictionary © Farlex 2012
n. pl. isth·muses or isth·mi (-mī′)
1. A narrow strip of land connecting two larger masses of land.
a. A narrow strip of tissue joining two larger organs or parts of an organ.
b. A narrow passage connecting two larger cavities.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
isthmusA narrow neck or portion of tissue connecting 2 structures.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
isth·mus, pl. isthmi (is'mŭs, -mī) [TA]
1. A constriction connecting two larger parts of an organ or other anatomic structure.
2. A narrow passage connecting two larger cavities.
3. The narrowest portion of the brainstem at the junction between midbrain and hindbrain.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012