[Plate 355, Uterus and Adnexa]Uterus
Basic structure
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Pear-shaped organ
Approximately 8 cm long and 5 cm wide
Supported by the pelvic diaphragm
Composed of
Body (corpus) -upper two thirds
Fundus-rounded upper part superior to the entrances of the uterine tubes
Isthmus-narrower area just above the cervix
Cervix (neck) -cylindrical inferior part that projects into the superior vagina
Uterine cavity is small (6 cm in length) and slit-like
Uterine horns are superolateral regions where the uterine (Fallopian tubes) enter
Uterine wall has three layers
Perimetrium-outer layer of peritoneum with underlying connective tissue
Myometrium-middle, thick layer of smooth muscle
Endometrium-vascular inner mucosal layer the thickness of which varies with menstrual cycle and age
The uterus has two surfaces: anteroinferior and posterosuperior
A portion of the cervix, body, and fundus of the uterus is covered with peritoneum
Cervix
Thick-walled canal, 2.5 cm long, connecting the body of the uterus with the vagina
Communicates superiorly via internal os with uterus
Communicates with vagina inferiorly via external os
Approximately half of the cervix lies above the vagina (supravaginal) and is covered posteriorly with the peritoneum of the rectouterine
pouch
The bladder is separated from the anterior surface of the supravaginal part of the cervix by connective tissue
The lower half of the cervix (vaginal part) protrudes into the vagina and can be examined clinicallyRelationships of the uterus
Laterally- Broad ligament, transverse cervical (cardinal ligaments), ureters