Right kidney

The right kidney, like the left, is a paired excretory organ responsible for urine formation, osmoregulation, and various metabolic functions. In most domestic mammals, the right kidney is:

• More cranial in position than the left kidney.

• Retroperitoneal and located in the sublumbar region, closely associated with the dorsal abdominal wall.

• Typically bean-shaped (reniform), except in certain species like the ox.

2. Topographical Anatomy

a. Dog and Cat

• Located opposite T13–L2 vertebrae.

• Lies in the renal fossa of the liver—a unique adaptation for close hepatic contact.

• Covered by the costal arch, making it harder to palpate.

• The renal hilus faces medially, with the ureter, renal artery, and renal vein arranged ventral to dorsal.

b. Ox (Bovine)

• The right kidney is distinctly lobated (multilobar and multipyramidal).

• Situated entirely to the right of the median plane, caudal to the liver.

• Lies opposite the last rib and the first three lumbar vertebrae.

• Renal lobes are externally visible, and no renal pelvis is present—urine drains via major calyces directly into the ureter.

c. Horse (Equine)

• Heart-shaped in external appearance.

• Located from T16 to L1, deep under the last few ribs and the transverse processes.

• Renal pelvis is present but has terminal recesses extending from it.

d. Pig (Porcine)

• Similar to the dog but more flattened and elongated.

• Lies from the last thoracic to the second lumbar vertebra.

• Multipapillate kidney with a well-developed pelvis and calyces system.

e. Small Ruminants (Goat, Sheep)

• Smooth, bean-shaped, similar to the dog.

• Positioned between L1 and L4, right kidney being more cranial.

• Has a well-defined cortex and medulla with a single renal papilla (unipyramidal).

3. Internal Structure

• Cortex: Granular and contains glomeruli, proximal and distal convoluted tubules.

• Medulla: Radially striated due to collecting ducts and loops of Henle.

• Renal pelvis (except in ox): Funnel-shaped structure where urine collects before entering the ureter.

• Renal sinus: Contains the pelvis, vessels, and fat.

4. Vascularization

• Arterial supply: From the right renal artery, branching directly off the abdominal aorta.

• Venous drainage: Into the right renal vein, which drains into the caudal vena cava.

• Segmental arteries give rise to interlobar, arcuate, and interlobular branches.

5. Innervation and Lymphatics

• Sympathetic innervation from the celiac and cranial mesenteric ganglia.

• Afferent fibers carry pain sensation.

• Lymphatic drainage is to the lumbar lymph nodes.