This tab covers the features specific to the female pelvis — the gynecologic ligaments, the uterine and ovarian vasculature, the external genitalia, the pelvic organs, and the female urethra — with emphasis on the ureter's vulnerability to injury near the uterine artery.
Bony Pelvis and Ligaments
The female pelvis has a wider diameter and a more oval inlet than the male. Key ligaments:
- Broad ligament — contains the fallopian tube and ovary, and is divided into mesometrium, mesosalpinx, and mesovarium; the mesometrium carries the gonadal vessels and nerves.
- Round ligament — runs within the broad ligament from the uterus, enters the internal inguinal ring, crosses the external iliac artery, traverses the inguinal canal, and ends in the labium majus; it is homologous to the male gubernaculum.
- Cardinal (transverse cervical) and uterosacral ligaments — within the parametrium; the cardinal ligament contains the uterine vessels, and the nerves of the inferior hypogastric plexus run with them — damage during hysterectomy can cause bladder dysfunction.
- Suspensory (infundibulopelvic) ligament of the ovary — contains the gonadal (ovarian) vessels.
Vasculature
- Uterine artery — from the anterior trunk of the internal iliac; it passes anterior to the ureter, so the ureter is vulnerable when the uterine pedicle is divided (it lies near the cervix).
- Ovarian artery — arises from the aorta below the renal arteries and is found at the infundibulopelvic ligament; it crosses the iliac vessels anterior and lateral to the ureter and joins the uterine artery.
- Ovarian vein — drains a pampiniform plexus: the right drains into the IVC, the left into the left renal vein (as in the male).
- Three structures are at risk in a sacrospinous-ligament vault suspension: the lateral sacral artery, the sacral plexus, and the pudendal nerve.
Innervation
- Sacral plexus (L4–S3) — exits the greater sciatic foramen just posterior to the sacrospinous ligament (motor/sensory to the posterior thigh and leg); at risk in sacrospinous vault suspension.
- Cavernous nerve — from the pelvic (inferior hypogastric) plexus; mediates clitoral engorgement.
- Pudendal nerve (S2–S4) — vulnerable during sacrospinous culdosuspension.
External Genitalia
- Clitoris — bounded by the labia minora laterally, the prepuce dorsally, and the frenulum ventrally; two corpora cavernosa split as crura onto the ischiopubic rami (surrounded by ischiocavernosus) and fuse distally as the glans.
- Labial fat pad — used in the Martius flap; supplied superiorly by the external pudendal, laterally by the obturator, and inferiorly by the posterior labial (internal pudendal) arteries.
- Bartholin (vestibular) glands — sit at the end of each bulb and empty between the hymen and labia minora; obstruction causes Bartholin gland cysts. They are analogous to the male bulbourethral (Cowper's) glands.
- Parasympathetic stimulation increases vaginal secretion and engorges the clitoris and erectile tissues; lymphatic drainage of the vulva, clitoris, and labia minora is to the inguinal nodes.
Pelvic Organs
- Uterus — composed of body and cervix and normally anteverted and anteflexed. The uterine artery crosses the ureter close to the cervix (giving it a small branch). The base of the bladder lies directly in front of the cervix on the anterior vaginal wall.
- Ovaries — lie in the ovarian fossa (bordered by the obliterated umbilical artery, ureter, and internal iliac artery), suspended by the infundibulopelvic ligament and attached to the uterus by the ovarian ligament. The ovarian artery (from the aorta) runs in the infundibulopelvic ligament and joins the uterine artery.
- Vagina — lined by non-keratinised stratified squamous epithelium (anterior wall ~7.5 cm, posterior ~9 cm); the ureters pass close to the lateral fornices, anterior to the vagina, as they enter the bladder. The lower quarter has somatic (pudendal) innervation.
- Ureter — crosses the infundibulopelvic ligament posterior to the ovarian artery and posterior and medial to the uterine artery, near the cardinal ligament and cervix.
- Pelvic organ support — the cardinal and uterosacral ligaments provide level I support (uterus, cervix, upper vagina); the paravaginal attachments to the arcus tendineus provide level II support; the anterior vagina supports the urethra.
Female Urethra
The female urethra is ~4 cm long, with a lining that changes from transitional to non-keratinised squamous. Periurethral glands — most prominently the Skene glands (opening just inside the meatus) — can obstruct and form diverticula. There is no internal urinary sphincter in females; the external urethral sphincter invests the distal two-thirds. Blood supply is from the inferior vesical, vaginal, and internal pudendal arteries. Clinical: incisions through the vaginal wall into the retropubic space should be made far lateral and parallel to the urethra to avoid denervating the striated sphincter. Pelvic MRI best characterises urethral diverticula and distinguishes them from benign vaginal cysts (müllerian, Gartner duct, epidermal inclusion, Bartholin, and Skene gland cysts).