The 2 kidneys are bean shaped organs approximately 12cm in length sitting either side of the spine at the level of the middle back.
They have many functions including removal of waste products from the body, production of urine and are important in controlling the body's water and salt balance.
The kidneys are also play an important role in controlling blood pressure.
KUB stands for kidney, ureter and bladder and it is a plain X-ray film to look at the urinary system and the abdomen as a whole. This plain X-ray usually reveals any obvious calcifications or stones within the urinary system.