Page kidney

The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about 12 centimetres (4 1⁄2 inches) in length. [Source: Wikipedia ]

Kidney compressed by perirenal collection
Kidney compressed by subcapsular collection
May Cause
Decreased renal artery diastolic flow
Increased resistance index of renal transplant
May Be Caused by
Perirenal abscess
Perirenal hematoma
Perirenal lymphocele
Perirenal urinoma