Female genital organs

Uterus

• Parts: fundus, body, isthmus (becomes the lower uterine segment in pregnancy), cervix (supravaginal and vaginal parts).
• Position: usually anteverted (cervix angled forward on the vagina, about 90°) and anteflexed (body bent forward on the cervix); about 20% are retroverted.
• Layers: endometrium, myometrium, perimetrium.
• The nulliparous external os is round; after vaginal delivery it becomes a transverse slit.
• In pregnancy the decidua capsularis fuses with the decidua parietalis (about the fourth month), obliterating the uterine cavity. Oestrogen everts endocervical columnar epithelium onto the ectocervix (ectropion).
• Nabothian follicles: smooth yellow-white cysts on the ectocervix where squamous metaplasia blocks endocervical gland openings; harmless.

Blood supply and the ureter

• Uterine artery (anterior division of internal iliac) runs medially in the base of the broad ligament and crosses above and in front of the ureter about 1.5–2 cm lateral to the cervix ("water under the bridge"), at about the level of the ischial spine. It ascends tortuously and anastomoses with the ovarian artery.
• The ureter is at risk when the uterine artery is clamped in hysterectomy, and when the ovarian vessels are tied at the pelvic brim.
• Advanced cervical cancer spreading laterally into the parametrium encases both ureters: bilateral hydronephrosis with an empty bladder and renal failure (stage IIIB regardless of tumour size).

Supports of the uterus and vagina

• The round ligament runs from the uterine cornu through the deep ring and inguinal canal to end in the labium majus. Lymph from around the cornu can follow it to superficial inguinal nodes.
• Weakness after childbirth (multiparity, prolonged labour, menopause, raised abdominal pressure) causes uterovaginal prolapse.

Broad ligament contents

Uterine tube (free edge), ovarian ligament, round ligament, uterine and ovarian vessels, ureter (at its base), lymphatics, nerves and mesonephric remnants: epoophoron, paroophoron and Gartner's duct (cysts in the lateral vaginal wall).

Uterine tubes

• Parts: intramural, isthmus (narrowest), ampulla (widest and longest: commonest site of fertilisation and ectopic pregnancy), infundibulum with fimbriae.
• Ciliated and secretory (peg) cells move the ovum; salpingitis damages them.
• Pelvic inflammatory disease (chlamydia, gonorrhoea) spreads from the tubes along the right paracolic gutter to the liver capsule: Fitz-Hugh–Curtis syndrome, with right upper quadrant pain and "violin-string" adhesions.
• Ectopic pregnancy: the endometrium still shows the Arias-Stella reaction (hypersecretory glands, large hyperchromatic nuclei, clear cytoplasm) without villi; transvaginal ultrasound is the key test. Rupture fills the rectouterine pouch, the lowest part of the female pelvis.

Ovaries

• Lie in the ovarian fossa: external iliac vessels above, ureter and internal iliac vessels behind, obturator nerve in the floor (ovarian disease can refer pain to the medial thigh).
• Suspensory (infundibulopelvic) ligament carries the ovarian vessels; the ovarian ligament joins the ovary to the uterus.
• Ovarian artery from the aorta at L2; right ovarian vein to the IVC, left to the left renal vein. Lymph to para-aortic nodes.
• Ovarian cancer spreads mainly transcoelomically: cells shed into peritoneal fluid seed the omentum, peritoneum and right hemidiaphragm, producing malignant ascites.

Vagina

• Anterior wall about 8 cm, posterior about 10 cm. The cervix forms the fornices; the posterior fornix is deepest and lies against the pouch of Douglas.
• Non-keratinised stratified squamous epithelium without glands; acidic pH from lactobacilli fermenting glycogen.
• Upper part from the paramesonephric ducts; lower part from the urogenital sinus (sinovaginal bulbs). This explains the split in lymph drainage.

Lymph drainage

Development and anomalies

• The uterus, tubes, cervix and upper vagina come from the paramesonephric (Müllerian) ducts; their lower ends fuse to make the uterus.

• An XX infant with virilised genitalia but normal uterus and ovaries suggests congenital adrenal hyperplasia.

Uterine and ovarian conditions

• Endometriosis: functioning endometrium outside the uterus, commonest in the ovary (chocolate cyst) and pouch of Douglas; best explained by retrograde menstruation through the tubes.
• Fibroids shrink with continuous GnRH agonist (goserelin): constant stimulation desensitises pituitary GnRH receptors, so FSH, LH and oestrogen fall after an initial flare.
• Theca lutein cysts: bilateral multicystic ovaries driven by very high hCG (molar pregnancy); they regress as hCG falls. The corpus luteum of pregnancy is the normal ovarian finding early in pregnancy.

Urinary fistula

Prolonged obstructed labour compresses the bladder base between the fetal head and pubis; ischaemic necrosis gives a vesicovaginal fistula with continuous vaginal leakage of urine days later.

Remember Water under the bridge: the ureter passes beneath the uterine artery 2 cm lateral to the cervix.

Exam trap The cardinal ligaments and pelvic floor support the uterus; the broad ligament does not.

Exam trap Lower vaginal cancer goes to superficial inguinal nodes; ovarian and fundal lymph go to para-aortic nodes.

How FCPS asks about this

• Ureter and uterine artery: ureter passes below the artery about 2 cm lateral to the cervix.
• Main support of the uterus: cardinal ligaments with the pelvic floor.
• Where the round ligament ends: labium majus, after traversing the inguinal canal.
• Bicornuate uterus: incomplete fusion of the Müllerian ducts.
• Site of fertilisation and ectopic pregnancy: ampulla of the uterine tube.
• Right upper quadrant pain after PID: spread along the right paracolic gutter (Fitz-Hugh–Curtis).
• Ovarian mass with ascites and pleural effusion that resolve after removal: fibroma (Meigs syndrome).