G1. Anatomy of Female Genitalia

I. External Genitalia

Vulva

• Vulva: all externally visible female genital structures from mons pubis to perineum.
• Components: mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulbs, greater vestibular glands.
• Vestibule: between labia minora; contains urethral opening, vaginal opening, Bartholin duct openings and Skene gland ducts.
• Blood/nerve/lymph: internal + external pudendal vessels, pudendal nerve, mainly superficial inguinal nodes.

Clitoris and Vestibular Glands

• Clitoris: erectile organ homologous to the male penis.
• Parts: glans, body/corpora cavernosa, two crura.
• Bartholin glands: greater vestibular glands at 4 and 8 o'clock of vaginal orifice.
• Function/homology: mucus secretion for lubrication; homologous to male bulbourethral glands.
• Clinical: normally non-palpable; painful unilateral swelling suggests Bartholin abscess.
• Skene glands: paraurethral glands opening beside urethra; often described as female prostate.

II. Vagina and Cervix

Vagina

• Vagina: tubular fibromuscular canal from vulva to cervix.
• Position: posterior to urethra/bladder and anterior to rectum.
• Epithelium: non-keratinized stratified squamous epithelium.
• Hymen: mucosal fold at vaginal introitus; practical anatomical border between external and internal genitalia.
• Blood supply: vaginal branches of uterine/internal iliac system.
• Lymph/innervation: lower vagina → superficial inguinal nodes + pudendal nerve; upper vagina → pelvic nodes + autonomic plexus.

Cervix

• Cervix: narrow inferior part of uterus projecting into the upper vagina.
• Portio vaginalis: vaginal part visible on speculum; external os opens into vagina, internal os into uterine cavity.
• Ectocervix: portion outside the external os; covered by non-keratinized stratified squamous epithelium.
• Endocervix: lined by mucus-producing columnar epithelium.
• Squamocolumnar junction/transformation zone: key site for HPV-related CIN and cervical cancer screening.
• Blood/nerve: cervical and vaginal branches of uterine artery; autonomic fibers from inferior hypogastric plexus.

III. Uterus and Tubes

Uterus

• Uterus: hollow muscular organ between bladder anteriorly and rectum posteriorly.
• Non-pregnant uterus: pelvic organ; in pregnancy enlarges into abdominal cavity.
• Parts: fundus, corpus, uterine cornua, cervix.
• Position: usually anteverted and anteflexed.
• Blood supply: uterine arteries from internal iliac arteries; anastomosis with ovarian arteries from aorta.
• Innervation: superior and inferior hypogastric plexuses.

Uterine Wall

• Endometrium: mucosal layer; cyclic hormone-dependent proliferation, secretion and shedding.
• Myometrium: smooth muscle layer responsible for menstruation-associated contractions and labor contractions.
• Perimetrium: outer serosal/peritoneal covering where present.
• Clinical: endometrium is target tissue for implantation, menstrual disorders, hyperplasia and endometrial carcinoma.

Fallopian Tubes

• Fallopian tubes: paired ducts from uterine cornua toward ovaries, running in the upper free edge of the broad ligament.
• Function: pick up oocyte, provide site for fertilization, transport embryo to uterine cavity.

1. Infundibulum: distal funnel-shaped part with fimbriae; catches ovulated oocyte.
2. Ampulla: widest and longest part; usual site of fertilization and common site of ectopic pregnancy.
3. Isthmus: narrow medial part near uterus.
4. Intramural / interstitial part: passes through uterine wall into uterine cavity.

IV. Ovaries and Support

Ovaries

• Ovaries: paired gonads on posterior aspect of broad ligament, attached by mesovarium.
• Function: oogenesis + steroid hormone production.
• Blood supply: ovarian arteries from abdominal aorta around L1; anastomose with uterine arteries.
• Venous drainage: right ovarian vein → inferior vena cava; left ovarian vein → left renal vein.
• Lymph drainage: para-aortic/lumbar nodes because ovaries develop high in the abdomen.

Ligaments and Pelvic Support

• Broad ligament: peritoneal fold containing uterus, tubes, vessels and connective tissue; not a strong support ligament.
• Ovarian ligament: ovary → uterus.
• Suspensory ligament of ovary / infundibulopelvic ligament: ovary → pelvic wall; contains ovarian vessels.
• Round ligament: uterine cornu → inguinal canal → labia majora; maintains anteversion.
• Cardinal ligament: cervix/lateral uterus → pelvic wall; contains uterine vessels.
• Uterosacral ligaments: cervix/upper vagina → sacrum; important apical support.
• Pelvic floor: levator ani + perineal body support pelvic organs and continence.