What is the name of the organ located on one side of the vertebral column, behind the peritoneum and the spleen, and lies against the deep muscles of the back?

Kidneys are the organs which are present besides the vertebral coloumn behind the peritoneum covered in a mass of fat and loose aerolar tissue along the posterior abdominal wall.

Explanation:

Kidneys are the bean shaped organs which are responsible for excretion and maintaining the pH and elctrolyte balance of the body. They are the part of urinary system.

There are two kidneys in the body.

They lie along the posterioir abdominal wall on the either side of the vertebral column behind spleen and peritoneum. This is because they are called retroperitoneal organs. Left kidney is slighlty higher than the right kidney because liver is present on the right side which pusehes the right kidney a little lower. They typically extend from T12 to L3. Kidneys are covered by a capsule, fibrous mass of tissue and fat and aerolar tissue.