Anatomical Relations
The kidneys sit in close proximity to many other abdominal structures which are important to be aware of clinically:
Anterior
Posterior
Left
- Suprarenal gland
- Spleen
- Stomach
- Pancreas
- Left colic flexure
- Jejunum
- Diaphragm
- 11th and 12th ribs
- Psoas major, quadratus lumborum and transversus abdominis
- Subcostal, iliohypogastric and ilioinguinal nerves
Right
- Suprarenal gland
- Liver
- Duodenum
- Right colic flexure
- Diaphragm
- 12th rib
- Psoas major, quadratus lumborum and transversus abdominis
- Subcostal, iliohypogastric and ilioinguinal nerves
Arterial Supply
The kidneys are supplied with blood via the renal arteries, which arise directly from the abdominal aorta, immediately distal to the origin of the superior mesenteric artery. Due to the anatomical position of the abdominal aorta (slightly to the left of the midline), the right renal artery is longer, and crosses the vena cava posteriorly.
The renal artery enters the kidney via the renal hilum. At the hilum level, the renal artery forms an anterior and a posterior division, which carry 75% and 25% of the blood supply to the kidney, respectively. Five segmental arteries originate from these two divisions.
The avascular plane of the kidney (line of Brodel) is an imaginary line along the lateral and slightly posterior border of the kidney, which delineates the segments of the kidney supplied by the anterior and posterior divisions. It is an important access route for both open and endoscopic surgical access of the kidney, as it minimises the risk of damage to major arterial branches.
Note: The renal artery branches are anatomical end arteries – there is no communication between vessels. This is of crucial importance; as trauma or obstruction in one arterial branch will eventually lead to ischaemia and necrosis of the renal parenchyma supplied by this vessel.
The segmental branches of the renal undergo further divisions to supply the renal parenchyma:
- Each segmental artery divides to form interlobar arteries. They are situated either side every renal pyramid.
- These interlobar arteries undergo further division to form the arcuate arteries.
- At 90 degrees to the arcuate arteries, the interlobular arteries arise.
- The interlobular arteries pass through the cortex, dividing one last time to form afferent arterioles.
- The afferent arterioles form a capillary network, the glomerulus, where filtration takes place. The capillaries come together to form the efferent arterioles.
In the outer two-thirds of the renal cortex, the efferent arterioles form what is a known as a peritubular network, supplying the nephron tubules with oxygen and nutrients. The inner third of the cortex and the medulla are supplied by long, straight arteries called vasa recta.
By TeachMeSeries Ltd (2023)
Fig 4 – Arterial and venous supply to the kidneys.
Myrto @ PatrasAnatomy
Fig 5 – Arterial supply to the kidney can be divided into five segments.