Clinical correlations in pelvis/perineum

Clinical correlations in pelvis/perineum

Clinical correlations in pelvis/perineum

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Pelvic Floor Dysfunction - Prolapse & Problems

  • Pathophysiology: Weakness of pelvic floor muscles (levator ani) & endopelvic fascia allows herniation of pelvic organs.
  • Risk Factors: Multiparity, advancing age, obesity, hysterectomy, chronic ↑ intra-abdominal pressure (e.g., constipation, chronic cough). Pudendal nerve (S2-S4) damage is a key contributor.
  • Types & Symptoms:
    • Cystocele (Anterior): Bladder prolapse; stress urinary incontinence.
    • Rectocele (Posterior): Rectal prolapse; constipation, splinting.
    • Uterine/Apical: Uterine descent; pelvic pressure.

⭐ First-line treatment for mild-moderate cases is conservative: Kegel exercises (pelvic floor muscle training) to strengthen the levator ani.

Female Pelvis: Normal vs. Uterine Prolapse

Pudendal Nerve Entrapment - Canal Calamity

  • Pathophysiology: Compression of the pudendal nerve (S2-S4), typically within the pudendal canal (Alcock's canal) or between the sacrospinous and sacrotuberous ligaments.
  • Etiology: Commonly seen in cyclists ("cyclist's syndrome"), post-childbirth, or after pelvic surgeries. Prolonged sitting is a major risk factor.
  • Clinical Triad:
    • Perineal pain (burning, tingling); classically worsens with sitting.
    • Sexual dysfunction (dyspareunia, erectile dysfunction).
    • Sphincter dysfunction (urinary/fecal incontinence).
  • Diagnosis & Management: Primarily clinical. A positive Tinel's sign over the ischial spine can be elicited. Pudendal nerve block is both diagnostic and therapeutic.

Pudendal nerve pathway & entrapment sites

⭐ Pain is characteristically relieved by standing or sitting on a toilet seat, as this posture reduces direct pressure over the pudendal canal.

Prostate Zonal Anatomy - Gland Gone Wild

Prostate zonal anatomy and relation to urethra (sagittal)

  • Peripheral Zone (~70%):
    • Largest part of the gland, located postero-laterally.
    • Common site for adenocarcinoma (>70% of cases).
    • Readily palpable on Digital Rectal Exam (DRE).
  • Transitional Zone (~5%):
    • Surrounds the proximal prostatic urethra.
    • Undergoes hypertrophy in Benign Prostatic Hyperplasia (BPH).
    • BPH compresses the urethra, causing Lower Urinary Tract Symptoms (LUTS).
  • Central Zone (~25%):
    • Wedge-shaped area surrounding the ejaculatory ducts.
    • Generally spared from both BPH and carcinoma.

⭐ Most prostate cancers arise in the posterior peripheral zone, so a palpable, firm nodule on DRE is highly suspicious for malignancy until proven otherwise.

Iatrogenic Injury - Water Under the Bridge

  • 📌 Mnemonic: "Water under the bridge" refers to the course of the ureters ("water") passing inferior to the uterine artery and ductus deferens ("the bridge").
  • Surgical Risk: This relationship is critical in pelvic surgeries. The ureter is vulnerable to injury during procedures like hysterectomy (ligating uterine artery) or oophorectomy (ligating ovarian vessels in the suspensory ligament).
  • Consequences: Unilateral ureteric injury can lead to hydronephrosis and silent loss of kidney function.

Pelvic Ureter Relations: Male vs. Female Anatomy

⭐ The ureter is most commonly injured during hysterectomy at the cardinal ligament, where the uterine artery crosses it to reach the uterus.

  • Pudendal nerve blocks target the ischial spine to anesthetize the perineum during childbirth.
  • The ureter is at high risk during hysterectomy near the uterine artery (“water under the bridge”).
  • Posterolateral episiotomy helps avoid injury to the perineal body and anal sphincter.
  • Radical prostatectomy can damage the pelvic splanchnic nerves, causing erectile dysfunction.
  • Levator ani weakness predisposes to pelvic organ prolapse, like cystocele or rectocele.
  • Straddle injuries can rupture the bulbous urethra, with urine extravasating into the superficial perineal pouch.

Practice Questions: Clinical correlations in pelvis/perineum

Test your understanding with these related questions

A 33-year-old woman comes to the emergency department because of a 1-hour history of severe pelvic pain and nausea. She was diagnosed with a follicular cyst in the left ovary 3 months ago. The cyst was found incidentally during a fertility evaluation. A pelvic ultrasound with Doppler flow shows an enlarged, edematous left ovary with no blood flow. Laparoscopic evaluation shows necrosis of the left ovary, and a left oophorectomy is performed. During the procedure, blunt dissection of the left infundibulopelvic ligament is performed. Which of the following structures is most at risk of injury during this step of the surgery?

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Flashcards: Clinical correlations in pelvis/perineum

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The _____ plexus innervates internal pelvic viscera

TAP TO REVEAL ANSWER

The _____ plexus innervates internal pelvic viscera

inferior hypogastric

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