The kidneys are bilateral bean-shaped organs, reddish-brown in colour and located in the posterior abdomen. Their main function is to filter and excrete waste products from the blood. They are also responsible for water and electrolyte balance in the body.
Metabolic waste and excess electrolytes are excreted by the kidneys to form urine. Urine is transported from the kidneys to the bladder by the ureters. It leaves the body via the urethra, which opens out into the perineum in the female and passes through the penis in the male.
In this article we shall look at the anatomy of the kidneys – their anatomical position, internal structure and vasculature.
By TeachMeSeries Ltd (2023)
Fig 1 – Overview of the urinary tract.
Anatomical Position
The kidneys lie retroperitoneally (behind the peritoneum) in the abdomen, either side of the vertebral column.
They typically extend from T12 to L3, although the right kidney is often situated slightly lower due to the presence of the liver. Each kidney is approximately three vertebrae in length.
The adrenal glands sit immediately superior to the kidneys within a separate envelope of the renal fascia.
Kidney Structure
The kidneys are encased in complex layers of fascia and fat. They are arranged as follows (deep to superficial):
- Renal capsule – tough fibrous capsule.
- Perirenal fat – collection of extraperitoneal fat.
- Renal fascia (also known as Gerota’s fascia or perirenal fascia) – encloses the kidneys and the suprarenal glands.
- Pararenal fat – mainly located on the posterolateral aspect of the kidney.
By TeachMeSeries Ltd (2023)
