Expansion
From T12 to L3, with the right kidney lying lower than the left
Expansion
- Retroperitoneal, on the posterior abdominal wall
- Extend from about T12 to L3
- The right kidney lies lower, pushed down by the liver
- The hila lie at the transpyloric plane (L1) - right just below, left just above
- Each is about 11 cm long, and moves 2 to 3 cm with respiration
Posterior relations include the diaphragm, psoas major, quadratus lumborum and transversus abdominis, with the twelfth rib crossing behind the upper pole (and the eleventh rib behind the left as well).
That rib relation matters: the pleura dips down behind the kidney, so a posterior approach for renal biopsy or percutaneous nephrolithotomy carries a risk of pneumothorax if the puncture is too high. Similarly, penetrating injury below the twelfth rib posteriorly may involve the kidney.