Pelvic Vasculature

Pelvic Vasculature - Pelvic Powerhouse

• Internal Iliac Artery (IIA): Primary arterial supply to pelvis; bifurcates into anterior & posterior divisions.

• Posterior Division: Supplies pelvic wall & gluteal region.
  • Key: Superior gluteal a. (largest branch).
• Anterior Division: Supplies pelvic viscera, perineum, medial thigh, gluteal region.
  • Key: Internal pudendal a. (perineum), Uterine a. (uterus), Obturator a. (adductors).

⭐ Uterine artery crosses superior to the ureter ("water under the bridge") approx. 2 cm lateral to the cervix. Critical landmark in hysterectomy.

• Ovarian Artery: Arises from abdominal aorta, supplies ovaries.
• Median Sacral Artery: Arises from posterior aorta, supplies sacrum/coccyx.

Pelvic Vasculature - Life Givers

• Internal Iliac Artery (IIA): Chief pelvic artery.
  • Posterior Division (Parietal):
    • Iliolumbar A.
    • Lateral Sacral A.
    • Superior Gluteal A. (Largest IIA branch)
    • 📌 Mnemonic: PILS (Posterior: Iliolumbar, Lateral sacral, Superior gluteal)
  • Anterior Division (Visceral & Parietal):
    • Visceral Branches:
      • Umbilical A. → Superior Vesical A. (→ A. to Ductus Deferens)
      • Inferior Vesical A. (♂) / Vaginal A. (♀)
      • Middle Rectal A.
      • Uterine A. (♀) - crosses superior to ureter ("water under the bridge")
      • Internal Pudendal A. (main perineal artery)
    • Parietal Branches:
      • Obturator A.
      • Inferior Gluteal A.

⭐ The Uterine Artery, from anterior division of IIA, passes superior to the ureter ("water under the bridge") - a key surgical landmark.

Pelvic Vasculature - Back & Beyond

• Internal Iliac Artery (IIA) - Posterior Division (Parietal Branches):
  • Iliolumbar a.: Supplies iliacus, psoas major, quadratus lumborum.
  • Lateral Sacral aa. (Superior & Inferior): Supply sacral canal structures, piriformis.
  • Superior Gluteal a.: Largest IIA branch; exits greater sciatic foramen (GSF) above piriformis. Supplies gluteal muscles.
• IIA - Anterior Division (Selected Parietal Branches):
  • Obturator a.: Exits via obturator canal. Supplies adductor muscles.
  • Inferior Gluteal a.: Exits GSF below piriformis. Supplies gluteal muscles, hamstrings.
• Other Key Arteries:
  • Median Sacral a.: Unpaired; from abdominal aorta bifurcation. Supplies sacrum, coccyx.
  • Gonadal aa. (Ovarian/Testicular): From abdominal aorta; supply gonads.

⭐ An aberrant obturator artery (variant origin, often from inferior epigastric a.) is found in approximately 20-30% of individuals. Its course over the superior pubic ramus creates the "corona mortis" (crown of death), a crucial surgical landmark due to high bleeding risk if injured, especially during hernia repair or pelvic fracture fixation.

Pelvic Vasculature - Drain & Defend

• Venous Drainage:

  • Internal Iliac Vein (IIV): Drains pelvic viscera, walls, perineum, gluteal. Mirrors IIA branches.
  • Gonadal Veins: Right → IVC; Left → Left Renal Vein.
  • Median Sacral Vein: Drains to Left Common Iliac Vein or IVC.
  • 📌 Batson's Plexus: Valveless vertebral veins. Metastasis route (e.g., prostate Ca to spine).

• Lymphatic Drainage: Generally follows arterial supply.

  • Key Nodal Groups:
    • Internal Iliac Nodes: Most pelvic viscera, deep perineum.
    • External Iliac Nodes: Upper bladder/cervix/vagina, lower limb.
    • Common Iliac Nodes: From internal/external iliac.
    • Para-aortic Nodes: Gonads, uterus, tubes; from common iliac.
    • Superficial Inguinal Nodes: Perineum, lower vagina, anal canal (distal to pectinate).

⭐ Cloquet's node (Rosenmüller's node) is the highest deep inguinal node, sentinel for penile/clitoral Ca.

High‑Yield Points - ⚡ Biggest Takeaways

• Internal iliac artery (IIA): main pelvic artery, with anterior & posterior divisions.
• IIA Posterior division: Iliolumbar, Lateral sacral, Superior gluteal (parietal).
• IIA Anterior division: supplies viscera (e.g., Uterine, Vesical) & perineum (Internal pudendal).
• Uterine artery crosses ureter superiorly ("water under the bridge") - critical surgical landmark.
• Internal pudendal artery: main perineal supply, via greater & lesser sciatic foramina.
• Ovarian (aortic branch) & Median sacral arteries contribute; pelvic veins drain to internal iliac vein.