CHAPTER 4: Anatomy

RENAL ARTERY

• Multiple possible sites of origin of the renal arteries, including but not limited to:¹

  • Lumbar arteries

  • Middle sacral artery

  • Main hilar renal artery

  • Common, external, or internal iliac arteries

  • Inferior phrenic artery

  • Gonadal artery

  • Suprarenal artery

  • Right colic artery

  • Twelfth intercostal artery

  • Right hepatic artery

  • Celiac trunk

  • Superior or inferior mesenteric arteries

  • Aorta

• Multiple renal arteries:^1,3–5

  • Embryologically, multiple renal arteries develop as persistent entities of the initial mesonephros:

    • The ascent of the embryologic kidney is normally accompanied by changes in its vascular supply, shifting from the iliac arteries while in the pelvic cavity to increasingly superior aspects of the abdominal aorta as it continues its ascent to its final resting position

  • Usually 1–3 additional arteries, but may reach up to 7

  • No significance between race and gender

  • Mean prevalence of 28% (11%–31%)

    • 87% incidence of unilateral multiple renal arteries

    • Of those kidneys with multiple renal arteries:

      • 6.5% incidence of prehilar branching

      • 22%–83% had 2 arteries

      • 4.5%–13% had 3 arteries

      • 1.4%–4% had 4 arteries

      • 0.2% had 5 arteries

    • In 30% of kidneys with multiple renal arteries, there was a short common trunk dividing into the main renal artery and a thinner artery

    • Multiple renal arteries on the left side were also found to emerge lower than the right ones and displayed a greater variability at origin

  • 23%–52% incidence on the right

  • 32%–48% incidence on the left

  • 10% incidence of bilateral additional renal arteries³

RENAL VEIN

• Single renal veins found in 92% of kidneys^2,4–8

• Multiple renal veins:

  • 0.4%–39% incidence^5,6

  • Greater incidence on the right side

  • 11%–28% on the right

  • 1%–2% on the left⁷

• Left renal vein:

  • 89% preaortic

  • 6% left preaortic with a small posterior branch similar to a lumbar vein

  • 2% retroaortic

  • 3% circumaortic

• No association between gender and renal vein variations

RENAL SEGMENTS

• Five renal anatomical segments (Superior, Anterior-Superior, Anterior-Inferior, Inferior, and Posterior) have been described based on arterial blood supply (Figures 4-1, 4-2, 4-3, and 4-4)¹³

• Such segmentation may show a greater or lesser degree of variation in as much as 50% of instances