Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
uterus[u´ter-us] (pl. u´teri) (L.)
The upper part of the uterus, or fundus uteri, is broad and flattened; the middle part (body), or corpus uteri, is large and open; and the lower part, or cervix uteri, is narrow and tubular and opens downward into the vagina. Two fallopian tubes enter the uterus at the upper end, one on each side. The walls of the uterus are composed of muscle, and its lining is mucous membrane. The muscular substance of the uterus is called the myometrium, and the inner lining is called the endometrium. Between puberty and menopause, the lining goes through a monthly cycle of growth and discharge, known as the menstrual cycle. menstruation is the time in the cycle when the tissue prepared by the uterus for a possible embryo or fertilized egg is unused and passes out through the vagina.
The menstrual cycle is interrupted by pregnancy when a mature ovum is fertilized by a spermatozoon. Fertilization usually takes place in the fallopian tube; the fertilized ovum continues moving along the tube and comes to rest in the uterus, where it implants in the endometrium. The endometrium then serves to anchor the placenta, which filters nutrients from the mother's blood into the blood of the growing fetus. (See also reproduction and female reproductive organs.)
u·ter·us di·del·phys(yū'tĕr-ŭs dī-del'fis)
uterus(ut'e-rus) [L. uterus, womb]
The uterus is a muscular, hollow, pear-shaped organ situated in the midpelvis between the sacrum and the pubic symphysis. Before child-bearing, it is about 3 in. (7.5 cm) long, 2 in. (5 cm) wide, and 1 in. ( 2.5 cm) thick. Its upper surface is covered by the perimetrium, and it is supported by the pelvic diaphragm supplemented by the two broad ligaments, two round ligaments, and two uterosacral ligaments. It is usually tilted forward over the top of the urinary bladder. The upper portion of the uterus, between the openings of the fallopian tubes, is the fundus; the large central portion is the body; and the narrow lower end is the cervix, which projects into the vagina. The cavity of the uterus is widest in the fundus. The canal of the cervix is narrow, opens into the uterine cavity at the internal os, and into the vagina at the external os.
The wall of the uterus consists of the outer perimetrium, middle myometrium, and inner endometrium. The uterine and ovarian arteries supply blood to the uterus.
Anteflexion: The uterus bends forward. Anteversion: The fundus is displaced forward toward the pubis, while the cervix is tilted up toward the sacrum. Retroflexion: The uterus bends backward at the junction of the body and the cervix. Retroversion: The uterus inclines backward with retention of the normal curve; this position is the opposite of anteversion.See: hysterectomy; pregnancy