Uterus | |
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Female internal reproductive anatomy | |
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1. Round ligament 2. Uterus 3. Uterine cavity 4. Intestinal surface of Uterus 5. Versical surface(toward bladder) 6. Fundus of uterus 7. Body of uterus 8. Palmate folds of cervical canal 9. Cervical canal 10. Posterior lip 11. Cervical os (external) 12. Isthmus of uterus 13. Supravaginal portion of cervix 14. Vaginal portion of cervix 15. Anterior lip 16. Cervix |
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Gray's | subject #268 1258 |
Artery | ovarian artery, uterine artery, helicine branches of uterine artery |
Vein | uterine veins |
Lymph | body and cervix to internal iliac lymph nodes, fundus to superficial inguinal lymph nodes |
Precursor | Müllerian duct |
MeSH | Uterus |
The uterus (Latin word for womb) is a major female reproductive organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation. The term uterus is used exclusively within the medical and related professions; some lay persons use the less formal term, womb. The plural of uterus is uteruses or uteri.
One end, the cervix, opens into the vagina; the other is connected on both sides to the Fallopian tubes.
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The main function of the uterus is to accept a fertilized ovum which becomes implanted into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, develops into a fetus and gestates until childbirth. Due to anatomical barriers such as the pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. Even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).
In mammals, the four main forms in which it is found are:
The uterus is located inside the pelvis immediately dorsal (and usually somewhat rostral) to the urinary bladder and ventral to the rectum. Outside of pregnancy, its size in humans is several centimeters in diameter. The uterus is a pear shaped muscular organ which can be divided anatomically into four segments: The fundus, corpus, cervix and the internal os.
From outside to inside, the path to the uterus is as follows:
The layers, from innermost to outermost, are as follows:
The uterus is primarily supported by the pelvic diaphragm and the urogenital diaphragm. Secondarily, it is supported by ligaments and the peritoneum (broad ligament of uterus) [1]
It is held in place by several peritoneal ligaments, of which the following are the most important (there are two of each):
Name | From | To |
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uterosacral ligament | the posterior cervix | the sacrum of pelvis |
cardinal ligaments | the side of the cervix | the ischial spines |
pubocervical ligament [1] |
Other named ligaments near the uterus, i.e. the broad ligament, the round ligament, the suspensory ligament of the ovary, the infundibulopelvic ligament, have no role in the support of the uterus.
Under normal circumstances the uterus is both "anteflexed" and "anteverted." The meaning of these terms are described below:
Distinction | More common | Less common |
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Position tipped | "anteverted": tipped forward | "retroverted": tipped backwards |
Position of fundus | "anteflexed": the fundus is pointing forward relative to the cervix | "retroflexed": the fundus is pointing backwards |
The bilateral Müllerian ducts form during early fetal life. In males, MIF secreted from the testes leads to their regression. In females these ducts give rise to the Fallopian tubes and the uterus. In humans the lower segments of the two ducts fuse to form a single uterus, however, in cases of uterine malformations this development may be disturbed. The different uterine forms in various mammals are due to various degrees of fusion of the two Müllerian ducts.
Some pathological states include:
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