The central portion of the kidney contains major and minor calyces and part of the renal pelvis. What is this central region called?

• A. Cortex
• B. Medulla
• C. Central
• D. Hilum

Answer: (C)

The central region that houses the major and minor calyces and part of the renal pelvis is the renal sinus, the central cavity of the kidney. In anatomy terms this central area is described as the renal sinus, so describing it as the central region fits—the other terms refer to different parts: the cortex is the outer shell, the medulla lies deeper with the pyramids and collecting ducts, and the hilum is the notch where vessels and the ureter connect, not the space that contains the calyces and pelvis. That’s why naming this area as central best matches its location and contents.