53 GYNAECOLOGY

# GYNAECOLOGY

👩‍⚕️ For MRCS Part A, gynaecology is mostly tested through pelvic anatomy and the pathology of the ovary, uterus and Fallopian tube. The high-yield areas are: nerve injuries during pelvic surgery, ligamentous support of the uterus, the ureter's relationship to the uterine artery, ectopic pregnancy, ovarian tumours and post-menopausal bleeding.

Detailed notes

Ligamentous support of the uterus

The uterus sits in the pelvis tilted forwards (anteverted) and bent forwards on itself (anteflexed). It is held in place by four pairs of ligaments — but only two of them genuinely support it. The rest position it.

➡ Cardinal (transverse cervical) ligaments — run from the cervix and lateral vaginal fornix to the lateral pelvic wall. Main structural support of the cervix. Carry the uterine artery and the crossing point with the ureter.

➡ Uterosacral ligaments — run from the cervix posteriorly to the sacrum. Together with the cardinals, prevent uterine prolapse.

➡ Round ligaments — embryological remnants of the gubernaculum. Pass through the deep ring and inguinal canal to the labium majus. Maintain anteversion but contribute almost nothing to support.

➡ Broad ligament — a peritoneal fold, not a true ligament. Drapes over the uterus, tubes and ovaries; contains the mesovarium, mesosalpinx and mesometrium.

Weakening of the cardinal and uterosacral ligaments — typically after multiple vaginal deliveries — is the cause of uterine prolapse.

👩‍⚕️ Exam trap: the broad ligament suspends but does not support. The round ligament positions but does not support. The answer to "main support of the cervix" is almost always the cardinal (transverse cervical) ligament.

Ovarian attachments

➡ Suspensory ligament of the ovary (infundibulopelvic ligament) — connects the ovary to the lateral pelvic wall and carries the ovarian artery, vein and lymphatics. This is the ligament ligated first during oophorectomy.

➡ Ovarian ligament — connects the ovary to the uterus (remnant of the gubernaculum, contiguous with the round ligament).

The ovarian artery arises directly from the abdominal aorta at L2. The right ovarian vein drains to the IVC; the left ovarian vein drains to the left renal vein (mirror image of the testicular veins).

The ureter and uterine artery — "water under the bridge"

At the level of the cervix, the ureter passes UNDER the uterine artery within the cardinal ligament, roughly 1–2 cm lateral to the cervix. The mnemonic is "water (ureter) under the bridge (uterine artery)."

This is the single most clinically important relationship in gynaecological surgery. During hysterectomy, the ureter is at high risk of injury when clamping the uterine vessels — clamps must hug the cervix.

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Nerves at risk in pelvic and gynaecological surgery

Nerve	Roots	Sensory territory	Motor	Classical injury
Iliohypogastric	L1	Suprapubic skin	—	Pfannenstiel / appendicectomy
Ilioinguinal	L1	Upper medial thigh, labium majus	—	Inguinal / lower transverse incisions
Genitofemoral	L1–L2	Groin (genital) + anterior mid-thigh (femoral)	Cremaster	Retroperitoneal / ovarian / psoas surgery
Obturator	L2–L4	Medial thigh	Adductors	Compression by pelvic mass; pelvic lymphadenectomy
Pudendal	S2–S4	Perineum, vulva	External anal sphincter, levator ani	Block for episiotomy / forceps delivery

👩‍⚕️ Remember the two classical contrasts: genitofemoral = surgical injury (groin + anterior mid-thigh), obturator = mass compression (inner thigh + adductor weakness).

Episiotomy

A surgical incision through the posterior vaginal wall and perineum to enlarge the vaginal outlet during the second stage of labour.

➡ Mediolateral incision (posterolateral, starting at the posterior fourchette and angled away at ~45° from the midline) is preferred over a midline cut.

➡ Midline episiotomy risks extension into the external anal sphincter (third-degree tear) and rectum (fourth-degree). Mediolateral avoids this.

➡ The incision cuts skin, the bulbospongiosus and superficial transverse perineal muscles, and occasionally part of the levator ani.

➡ Angled to avoid Bartholin's gland (at the 4 and 8 o'clock positions of the vaginal opening).

➡ Pudendal nerve block (S2–S4) provides analgesia — landmark is the ischial spine, palpated transvaginally.

Ectopic pregnancy

Implantation of a fertilised ovum outside the uterine cavity. The ampulla of the Fallopian tube is by far the commonest site (~70%), followed by the isthmus, fimbrial end, ovary, cervix and abdomen.

➡ Risk factors — previous ectopic, pelvic inflammatory disease (tubal scarring), tubal surgery, IUCD in situ, IVF, endometriosis, smoking, increasing age.

➡ Presentation — 6–8 weeks amenorrhoea, unilateral pelvic pain, PV bleeding, shoulder-tip pain (diaphragmatic irritation from haemoperitoneum), haemodynamic collapse if ruptured.

➡ Investigation — serum β-hCG that fails to double in 48 hours, transvaginal ultrasound (empty uterus + adnexal mass).

➡ Management — expectant if β-hCG falling and patient stable; medical with methotrexate (β-hCG < 1500, unruptured, no fetal heartbeat, mass < 35 mm); surgical salpingectomy (laparoscopic) if ruptured, large or contralateral tube healthy.

👩‍⚕️ Exam trap: an IUCD reduces the absolute risk of pregnancy, but if pregnancy occurs with one in situ, the chance of it being ectopic is dramatically higher.

Ovarian cysts and tumours

Functional (benign, commonest in young women)

➡ Follicular cyst — unruptured Graafian follicle.

➡ Corpus luteum cyst — failure of regression.

Benign neoplasms

➡ Mature cystic teratoma (dermoid cyst) — commonest ovarian germ cell tumour in young women. Contains derivatives of all three germ layers (skin, hair, teeth, fat, thyroid, neural tissue). Malignant transformation in 1–2%, usually to squamous cell carcinoma. Risk of torsion due to weight.

➡ Serous and mucinous cystadenomas.

➡ Fibroma — part of Meigs' syndrome (ovarian fibroma + ascites + right pleural effusion).

Malignant

➡ Epithelial ovarian cancer — most common type overall; subtypes include serous (commonest), mucinous, endometrioid, clear cell.

➡ Germ cell tumours — younger women; dysgerminoma, yolk sac, choriocarcinoma.

➡ Sex-cord stromal — granulosa cell (oestrogen-secreting, post-menopausal bleeding), Sertoli–Leydig (androgenic).

➡ Krukenberg tumour — metastasis to ovary, classically from gastric signet-ring cell carcinoma.

Ovarian cancer — exam essentials

➡ "Silent killer" — vague abdominal symptoms (bloating, early satiety, urinary frequency); usually presents late (stage III/IV).

➡ Tumour marker CA-125 (also raised in endometriosis, fibroids, PID, pregnancy — not specific).

➡ Risk factors: nulliparity, early menarche/late menopause, HRT, BRCA1/2, Lynch syndrome.

➡ Protective: combined OCP, multiparity, breastfeeding (each reduces ovulation).

Ovarian torsion — surgical emergency. Sudden severe unilateral pain, nausea, palpable mass. USS shows enlarged ovary with absent Doppler flow. Detorsion + cystectomy; oophorectomy only if necrotic.

Endometrial pathology

➡ Endometrial carcinoma is the commonest gynaecological malignancy in the UK. Classically presents with post-menopausal bleeding (PMB) — until proven otherwise, PMB is endometrial cancer.

➡ Risk factors are essentially unopposed oestrogen exposure: obesity, nulliparity, late menopause, tamoxifen, PCOS, oestrogen-only HRT, Lynch syndrome.

➡ Investigation: transvaginal USS (endometrial thickness > 4 mm post-menopause) + endometrial biopsy (Pipelle or hysteroscopy).

Endometriosis

Ectopic endometrial tissue outside the uterine cavity — commonly ovaries (chocolate cysts), uterosacral ligaments, pouch of Douglas. Cyclical bleeding into these deposits causes inflammation, adhesions and fibrosis.

➡ Triad: cyclical pelvic pain, dysmenorrhoea, dyspareunia. Often subfertility.

➡ Gold-standard diagnosis: laparoscopy with biopsy.

➡ Adenomyosis = endometrial tissue within the myometrium (boggy, tender, bulky uterus).

Pelvic inflammatory disease (PID)

Ascending infection of the upper female genital tract — usually sexually transmitted.

➡ Commonest organisms: Chlamydia trachomatis and Neisseria gonorrhoeae.

➡ Presents with bilateral lower abdominal pain, deep dyspareunia, abnormal discharge, cervical motion tenderness ("cervical excitation").

➡ Complications: tubal scarring → infertility and ectopic pregnancy, chronic pelvic pain, tubo-ovarian abscess, and Fitz-Hugh–Curtis syndrome (perihepatitis — RUQ pain with "violin-string" adhesions between liver capsule and diaphragm).

Fibroids (leiomyomas)

Benign smooth-muscle tumours of the myometrium, oestrogen-dependent.

➡ Commonest benign tumour of the female pelvis; more common and larger in Afro-Caribbean women.

➡ May be submucosal, intramural or subserosal (pedunculated subserosal may tort).

➡ Symptoms: menorrhagia (commonest), pressure effects, subfertility, dysmenorrhoea.

➡ Classic exam association: red degeneration in pregnancy — acute pain from infarction as the fibroid outgrows its blood supply.

➡ Regress after menopause.

Caesarean section anatomy

The standard lower-segment (Pfannenstiel) approach. Layers traversed:

1. Skin

2. Camper's and Scarpa's fascia

3. Anterior rectus sheath

4. Rectus abdominis (split in the midline, not cut)

5. Transversalis fascia

6. Extraperitoneal fat

7. Parietal peritoneum

8. Visceral peritoneum reflected off the lower uterine segment

9. Lower uterine segment — transverse incision

The lower segment is preferred because it is thinner, less vascular, heals better and lowers the risk of uterine rupture in future pregnancies. The ureters and bladder are at risk — the bladder is reflected inferiorly before incising the uterus.

[Image: MCQs banner]

Test yourself

A pregnant woman is about to undergo episiotomy for labour. Which nerve is blocked?

• ((Internal pudendal::☑️ S2–S4; supplies perineum and vulva — blocked at the ischial spine for episiotomy.))
• ((Obturator::Supplies medial thigh adductors, not the perineum.))
• ((Ilioinguinal::Supplies suprapubic skin and upper medial thigh.))
• ((Inferior gluteal::Motor only — supplies gluteus maximus.))

👩‍⚕️ Landmark for the block is the ischial spine, palpated transvaginally.

A patient undergoes ovarian surgery and postoperatively develops numbness over the groin and anterior mid-thigh. Which nerve is most likely injured?

• ((Obturator nerve::Inner thigh sensory loss plus adductor weakness — not mid-thigh.))
• ((Genitofemoral nerve::☑️ L1–L2; genital branch supplies groin, femoral branch supplies anterior mid-thigh.))
• ((Iliohypogastric nerve::Suprapubic skin only — injured in Pfannenstiel incisions.))
• ((Ilioinguinal nerve::Upper medial thigh and labium majus, not anterior mid-thigh.))

👩‍⚕️ Genitofemoral = surgical injury; obturator = mass compression.

A patient with a large ovarian mass develops numbness on the inner thigh. Which nerve is compressed?

• ((Femoral::Anterior thigh and medial leg via saphenous; not isolated inner thigh.))
• ((Ilioinguinal::Upper medial thigh and external genitalia only.))
• ((Obturator::☑️ Runs along the pelvic side wall; classically compressed by pelvic masses.))
• ((Sciatic::Posterior thigh and entire leg below the knee.))

Which structure provides the main support of the cervix?

• ((Broad ligament::Peritoneal fold — suspends but does not support.))
• ((Ovarian ligament::Connects ovary to uterus only.))
• ((Round ligament::Maintains anteversion; minimal support.))
• ((Transverse cervical (cardinal) ligament::☑️ Anchors cervix to lateral pelvic wall; carries uterine artery.))

👩‍⚕️ Weakening of cardinal and uterosacral ligaments causes uterine prolapse.

A 42-year-old multiparous woman presents with uterine prolapse. Which structure gives the most direct support?

• ((Round ligaments::Maintain anteversion; do not prevent prolapse.))
• ((Central perineal tendon::Supports pelvic floor, not the uterus directly.))
• ((Ovarian ligaments::Connect ovary to uterus — non-supportive.))
• ((Cervical ligaments::☑️ Cardinal and uterosacral ligaments — the main anti-prolapse structures.))

Histology of an excised ovarian cyst in a 20-year-old shows keratinising squamous epithelium with fat, muscle, thyroid and neural tissue. Diagnosis?

• ((Cystadenoma::Benign epithelial tumour lined by columnar epithelium.))
• ((Dysgerminoma::Malignant germ cell tumour — sheets of primitive cells, no mature tissues.))
• ((Mesenchymoma::Rare; mesenchymal elements only.))
• ((Teratoma::☑️ Mature cystic teratoma (dermoid) — derivatives of all three germ layers.))

👩‍⚕️ Dermoid is the commonest ovarian germ cell tumour in young women; 1–2% undergo malignant change, usually to SCC.

During hysterectomy, the ureter is most at risk where it passes:

• ((Over the pelvic brim at the bifurcation of the common iliac::True anatomically but not the operative danger point in hysterectomy.))
• ((Under the uterine artery, 1–2 cm lateral to the cervix::☑️ "Water under the bridge" — clamping uterine vessels risks ureteric injury here.))
• ((Through the obturator canal::The obturator nerve passes here, not the ureter.))
• ((Behind the bladder trigone::The ureter enters the bladder here but is not at risk during hysterectomy.))

Which is the commonest site of ectopic pregnancy?

• ((Isthmus of Fallopian tube::Second commonest tubal site; highest rupture risk.))
• ((Ampulla of Fallopian tube::☑️ ~70% of ectopics implant here.))
• ((Ovary::Rare — under 3%.))
• ((Cervix::Very rare; high haemorrhage risk.))

👩‍⚕️ PID, previous ectopic, tubal surgery and IUCD in situ are the classic risk factors.

A 65-year-old woman presents with post-menopausal bleeding. The most likely diagnosis is:

• ((Atrophic vaginitis::Common cause but a diagnosis of exclusion.))
• ((Cervical ectropion::Typical in young women on the OCP.))
• ((Endometrial carcinoma::☑️ PMB is endometrial cancer until proven otherwise — investigate with TVUS and biopsy.))
• ((Fibroids::Regress after menopause; rarely cause PMB.))

A woman with advanced gastric signet-ring adenocarcinoma is found to have bilateral solid ovarian masses. The likely diagnosis is:

• ((Bilateral serous cystadenocarcinoma::Primary epithelial cancer — usually cystic, not the context here.))
• ((Krukenberg tumour::☑️ Metastasis to ovaries, classically from gastric signet-ring carcinoma.))
• ((Dysgerminoma::Germ cell tumour of young women; unrelated to GI primary.))
• ((Granulosa cell tumour::Oestrogen-secreting; presents with PMB, not GI primary.))

Revision summary

➡ Cardinal + uterosacral ligaments = main support of cervix; weakening causes prolapse.

➡ Suspensory ligament of ovary carries the ovarian vessels.

➡ Ureter passes UNDER the uterine artery at the cervix — "water under the bridge."

➡ Pudendal nerve block (S2–S4, at ischial spine) for episiotomy; mediolateral preferred to avoid anal sphincter and Bartholin's gland.

➡ Genitofemoral injury (surgery) = groin + anterior mid-thigh numbness.

➡ Obturator compression (pelvic mass) = inner thigh numbness + adductor weakness.

➡ Ectopic pregnancy — ampulla commonest; β-hCG + TVUS; methotrexate vs salpingectomy.

➡ Dermoid cyst (mature cystic teratoma) = commonest ovarian germ cell tumour in young women; all three germ layers.

➡ Ovarian cancer — epithelial (serous) commonest; CA-125; presents late; BRCA, nulliparity, HRT.

➡ Krukenberg = bilateral ovarian metastases from gastric signet-ring carcinoma.

➡ Endometrial cancer = commonest gynae malignancy in UK; PMB until proven otherwise; unopposed oestrogen.

➡ PID — Chlamydia/Gonorrhoea → infertility, ectopic, chronic pain, Fitz-Hugh–Curtis.

➡ Fibroids — oestrogen-dependent; menorrhagia; red degeneration in pregnancy; regress post-menopause.

➡ Endometriosis — cyclical pain, dysmenorrhoea, dyspareunia, subfertility; laparoscopy is gold standard.

➡ LSCS — lower segment is thinner, less vascular, lower rupture risk; bladder reflected before uterine incision.