isthmus

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isthmus

 [is´mus]
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 thyroid gland, connecting the two lobes. From Dorland's, 2000.
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.

isth·mus

, pl.

isth·mi

,

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.
[G. isthmos]

isthmus

/isth·mus/ (is´mus) pl. isth´mi   a narrow connection between two larger bodies or parts.isth´mian
isthmus of auditory tube , isthmus of eustachian tube the narrowest part of the auditory tube at the junction of its bony and cartilaginous parts.
isthmus of fauces  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 gland  the band of tissue joining the lobes of the thyroid gland.
isthmus of uterine tube  the narrower, thicker-walled portion of the uterine tube closest to the uterus.
isthmus of uterus  the constricted part of the uterus between the cervix and the body of the uterus.

isthmus

(ĭs′məs)
n. pl. isth·muses or isth·mi (-mī′)
1. A narrow strip of land connecting two larger masses of land.
2. Anatomy
a. A narrow strip of tissue joining two larger organs or parts of an organ.
b. A narrow passage connecting two larger cavities.

isthmus

[is′məs] pl. isthmuses, isthmi
Etymology: Gk, isthmos, a narrow connection, passage, or constriction
a constriction between two larger parts of an organ or anatomical structure, such as the isthmus of the thyroid.

isthmus

A narrow neck or portion of tissue connecting 2 structures.

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.
[G. isthmos]

isthmus

a narrow connection between two larger bodies or parts.

aortic isthmus
that part of the aorta between the origin of the brachiocephalic trunk, or the left subclavian artery, and that of the ductus arteriosus which is partly constricted in the fetus; it marks the partial separation of fetal blood flow derived from right and left ventricles, and is most conspicuous in the newborn calf.
isthmus of auditory tube
the narrowest part of the pharyngotympanic tube at the junction of its bony and cartilaginous parts. Called also isthmus of pharyngotympanic tube.
isthmus of fauces, isthmus faucium
the constricted aperture between the cavity of the mouth and the pharynx.
oviduct isthmus
the short slightly narrower section of the oviduct of the bird between the magnum and the uterus, where the shell membranes are laid down.
pharyngeal isthmus
the aperture between the dorsal and ventral parts of the pharynx and separated by the free edge of the soft palate and the palatopharyngeal arch.
isthmus of pharyngotympanic tube
see isthmus of auditory tube (above).
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. It is fibrous in sheep and horses and glandular in dogs and cattle.
isthmus of uterine tube
the narrower, thicker-walled portion of the uterine tube closest to the uterus.