What is the normal sonographic appearance of the kidney?
The adult kidney usually measures 9 to 13 cm in length. The renal cortex is normally isoechoic to hypoechoic compared to the liver and hypoechoic compared to the spleen. Renal medullary pyramids are hypoechoic relative to the renal cortex. The renal sinus is predominantly composed of fat and is hyperechoic.