Which statement describes a normal right kidney on ultrasound?

• A. Right kidney length about 10 cm from pole to pole and hypoechoic relative to liver
• B. Right kidney length about 6 cm
• C. Right kidney is hyperechoic relative to liver
• D. Left kidney length about 10 cm

Answer: (A)

A normal right kidney on ultrasound should have a length in the adult range and a mild echogenicity that is lower than the liver. In adults, the kidney length is typically about 9–12 cm; describing the right kidney as around 10 cm fits within normal limits. The renal cortex is normally less echogenic than the liver, so the kidney appears hypoechoic relative to the liver.

So the best description matches a right kidney about 10 cm in length with cortex that is hypoechoic compared with the liver. A length of 6 cm would be abnormally small, a hyperechoic kidney relative to the liver suggests pathology, and mentioning the left kidney does not describe the right kidney.