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In anatomy, isthmus refers to a constriction between organs. This is a list of anatomical isthmi:
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Aortic isthmus, section of the aortic arch
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Cavo-tricuspid isthmus of the right atrium of the heart, a body of fibrous tissue in the lower atrium between the inferior vena cava, and the tricuspid valve
* Isthmus, the ear side of the
eustachian tube
* Isthmus, narrowed part between the trunk and the splenium of the
corpus callosum
The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental m ...
* Isthmus, formation of the shell membrane in
birds oviduct's
* Isthmus lobe, lobe in the
prostate
The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and phys ...
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Isthmus of cingulate gyrus
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Isthmus of fauces, opening at the back of the mouth into the throat
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Isthmus organizer, secondary organizer region at the junction of the midbrain and metencephalon
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Isthmus tubae uterinae, links the fallopian tube to the uterus
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Kronig isthmus, band of resonance representing the apex of lung
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Thyroid isthmus
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thy ...
, thin band of tissue connecting some of the lobes that make up the thyroid
*
Uterine isthmus
The uterine isthmus is the inferior-posterior part of uterus, on its cervical end — here the uterine muscle ( myometrium) is narrower and thinner. It connects the body and cervix.
The uterine isthmus can become more compressibile in pregnanc ...
, inferior-posterior part of uterus
Isthmus
An isthmus (; ; ) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea counterpart of an isthmus ...
Anatomical isthmus