Myometrium

The myometrium is the middle layer of the uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue.

The inner layer of the uterine wall is the endometrium or uterine lining, and the outer layer the serosa or peritoneum. The myometrium stretches (the smooth muscle cells expand in both size and number^[1]) during pregnancy to allow for the harboring of the pregnancy, and contracts in a coordinated fashion during the process of labor. After delivery the myometrium contracts to expel the placenta and reduce blood loss.

Lack of contraction at this stage is termed uterine atony. After pregnancy the uterus returns to its nonpregnant size by a process of myometrial involution.

Pathology

Neoplasms of the myometrium are very common, termed uterine leiomyomata or fibroids. Their malignant version, leiomyosarcoma, is rare.

External links

• Histology at USC rep/c_52
• MeSH Myometrium

Female reproductive system
Follicles/Folliculogenesis	corpus (hemorrhagicum, luteum, albicans) • Theca folliculi (externa, interna) • Follicular antrum (Follicular fluid) • Corona radiata • Zona pellucida • Membrana granulosa (Granulosa cells)
Ovaries/Oogenesis	Germinal epithelium • Tunica albuginea • cortex (Cumulus oophorus, Stroma) • Medulla
Fallopian tubes	Isthmus • Ampulla • Infundibulum • Fimbria
Ligaments	Broad (components: Mesovarium, Mesosalpinx, Mesometrium contents: Round of uterus, Proper of ovary) • Suspensory of ovary • Cardinal
Uterus	cervix/neck (External orifice - Canal of the cervix, Internal orifice) • corpus/body (Cavity of the body, Fundus) • layers (Endometrium, Myometrium, Perimetrium) • Uterine horns
Vulva/mons pubis	Labium: commissures (Anterior • Posterior) • Frenulum labiorum pudendi • Labia majora • Cleft of venus • Labia minora • Vulval vestibule • interlabial sulci Clitoris: Vestibular bulbs • Clitoral crura • Corpus cavernosa • Clitoral glans (Frenulum, Hood) Vagina: vestibular glands/ducts (Bartholin's glands/Bartholin's ducts, Skene's glands/Skene's ducts) • Fossa of vestibule of vagina • Vaginal fornix • Hymen • Orifice
Vestiges	Wolffian (Gartner's duct, Epoophoron, Paroöphoron) • Canal of Nuck
Other	G-spot • Urethral sponge