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🫀 ANATOMY IMPORTANT QUESTIONS — COMPLETE NOTES

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1. UTERUS — Anatomy, Clinical Correlations & Cases

Structure

• Thick-walled muscular organ in the midline, between bladder (anterior) and rectum (posterior)
• Parts: Fundus (above uterine tubes), Body, Cervix, and it joins the Vagina inferiorly
• The cavity of the body = narrow slit laterally; inverted triangle shape anteriorly
• Superior corners → continuous with uterine tube lumina; inferior corner → continuous with cervical canal
• During pregnancy, the uterus expands dramatically superiorly into the abdominal cavity

Ligaments (Supports of Uterus)

• Also supported by: perineal membrane, levator ani, perineal body

Cervix & Vaginal Fornices

• The cervix is a dome-shaped structure visible on speculum examination
• Vaginal fornices surround it (anterior, posterior, lateral)
• Posterior fornix is closely related to the recto-uterine pouch (Pouch of Douglas)

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⚕️ Clinical Correlations & Cases

1. Hysterectomy

• Surgical removal of uterus (body + fundus + cervix ± ovaries & tubes)
• Full: Total Abdominal Hysterectomy + Bilateral Salpingo-Oophorectomy (TAH + BSO)
• Indications: uterine/cervical/ovarian cancer, endometriosis, excessive bleeding, postpartum hemorrhage
• Done via transverse suprapubic incision
• ⚠️ Key danger: The ureter runs close to the uterine artery — "water under the bridge" — risk of ureteric injury during ligation of uterine arteries

2. Recto-Uterine Pouch (Pouch of Douglas)

• Lies between rectum and uterus — lowest part of the abdominopelvic cavity in supine position
• Site of collection of pus, blood, or peritoneal fluid
• Cannot be palpated transabdominally — examined by transvaginal or transrectal digital palpation
• If abscess → drained via posterior vaginal wall (culdocentesis / posterior colpotomy)

3. Uterine Prolapse

• Weakness of cardinal (transverse cervical) ligaments + pelvic diaphragm → uterus descends
• Classified as 1st, 2nd, 3rd degree (procidentia = complete prolapse)

4. Implantation abnormalities

• Normal implantation = body of uterus
• Ectopic pregnancy = implantation in uterine tube (ampulla most common) → risk of rupture → hemoperitoneum collecting in Pouch of Douglas

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2. ISCHIO-ANAL (ISCHIO-RECTAL) FOSSA

Shape & Location

• Inverted wedge-shaped gutters on either side of the anal aperture, in the anal triangle
• Walls:
  • Lateral wall: ischium + obturator internus muscle + sacrotuberous ligament
  • Medial wall: levator ani muscle
  • Medial & lateral walls converge superiorly where levator ani attaches to fascia of obturator internus

Contents

• Fat (fills the fossa — allows movement of pelvic diaphragm and expansion of anal canal during defecation)
• Pudendal nerve + internal pudendal vessels — pass through the pudendal canal (Alcock's canal) in the lateral wall
• Inferior rectal nerves and vessels cross the fossa to reach external anal sphincter

Anterior Recesses

• The ischio-anal fossae extend anteriorly as recesses into the urogenital triangle, superior to the deep perineal pouch
• These recesses = three-sided pyramid shape, apex pointing anteriorly toward pubis

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⚕️ Clinical Correlation — Ischio-anal Abscess

• Anal mucosa can be torn by hard feces → infection of anal sinuses/crypts
• Infection can spread:
  • Between sphincters → intersphincteric fistula
  • Superiorly → pelvic cavity
  • Laterally → ischio-anal fossa abscess (most common perianal abscess)
• The fat-filled fossa is a good medium for bacterial proliferation → painful perianal swelling
• If untreated → horseshoe abscess (crosses midline via posterior communication)
• Treatment: Surgical drainage

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3. OVARIAN FOSSA

Definition

• A depression of the peritoneum on the lateral wall of the pelvis

Boundaries

Position of Ovary

• In a nulliparous adult woman: ovary lies in the ovarian fossa
• In multiparous women: ovary is usually somewhat lower
• The ureter is closely related — separated from ovary only by parietal peritoneum

Support of Ovary

• Mesovarium — peritoneal fold anchoring it to the posterior broad ligament
• Suspensory ligament of ovary (infundibulopelvic ligament) — contains ovarian vessels, attaches to superior pole
• Ligament of ovary — from inferior pole to tubal angle of uterus

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⚕️ Clinical Note

• Ovarian cancer (80–90% of ovarian tumors) arises from the epithelial surface of the ovary
• The ovary is NOT covered by peritoneum (covered by germinal epithelium = modified peritoneum) — explains peritoneal spread
• Because of proximity of ureter to the ovarian fossa, ureteric injury is a risk during oophorectomy

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4. PERINEAL POUCHES & PERINEAL BODY

Perineal Membrane

• Thick fibrous sheet filling the urogenital triangle
• Has a free posterior border anchored in midline to the perineal body
• Attached laterally to pubic arch
• Functions: supports external genitalia + pelvic viscera (below the urogenital hiatus)

Deep Perineal Pouch

• Immediately superior to the perineal membrane
• Contains:
  • External urethral sphincter (skeletal muscle)
  • Deep transverse perineal muscle
  • Neurovascular tissues
• In women: urethra AND vagina pass through the deep perineal pouch and perineal membrane

Superficial Perineal Pouch

• Inferior to the perineal membrane
• Contains:
  • Erectile structures: crura of clitoris/penis (attached to pubic arch), bulbs of vestibule (women) / corpus spongiosum (men)
  • Skeletal muscles: ischiocavernosus, bulbospongiosus, superficial transverse perineal
  • In women: bulbs of vestibule flank the vaginal opening; glans clitoris at midline anteriorly

Perineal Body

• A fibromuscular node in the midline, at the junction of the urogenital and anal triangles
• Convergence point for multiple muscles:
  • External anal sphincter
  • Bulbospongiosus
  • Superficial and deep transverse perinei
  • Levator ani (pubovaginalis)
• Clinical importance: Torn during difficult childbirth → episiotomy to prevent uncontrolled tear

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5. PROSTATE — Pathology & HBC Clinicals

Zones of Prostate

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A. Prostatitis

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B. Benign Prostatic Hyperplasia (BPH)

• Most common benign prostatic disease in men >50 years; rises to 90% by 8th decade
• Zone: Transition zone (inner glands) → compresses urethra to slit-like orifice
• Pathogenesis: DHT (from testosterone via 5α-reductase type 2) drives stromal + glandular proliferation
  • DHT is 10× more potent than testosterone
  • Estrogen (levels relatively ↑ with age) acts synergistically

• Prostate weight: 60–100 g (normal ~20 g)
• Microscopy: hyperplastic glands lined by tall columnar epithelium + peripheral basal cell layer (key: basal cells PRESENT — distinguishes from carcinoma)
• Corpora amylacea = laminated proteinaceous material in lumina

• Urinary frequency, nocturia, difficulty starting/stopping stream, overflow dribbling, dysuria
• Residual urine → bacterial infections (cystitis, pyelonephritis)
• Can → hydronephrosis if complete obstruction

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C. Carcinoma of the Prostate

• Most common cancer in men — 21% of male cancer cases; 2nd leading cause of cancer death in men
• Largely a disease of aging: 20% in 50s → ~70% in 70–80 years (autopsy studies)
• Zone: Peripheral zone → palpable on Digital Rectal Examination (DRE)
• African American men have >2× the death rate (partly due to unequal access to screening)

• Androgens, heredity, environmental factors, acquired somatic mutations

• Malignant glands lack basal cell layer (vs BPH — basal cells present)
• Gleason grading system (grades 1–5; sum = Gleason score)

• Old man + nocturia + weak stream + elevated PSA → BPH vs Prostate Ca → need TRUS-guided biopsy
• DRE: BPH = smooth, rubbery enlargement; Carcinoma = hard, irregular, nodular
• Acute bacterial prostatitis: Never do DRE → order urine culture instead
• Bone pain in elderly man + elevated PSA → osteoblastic metastases to spine (prostate ca → blastic lesions)

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Quick Memory Tricks

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