Left renal artery

At a glance

English

Left renal artery

Latin (TA2)

Arteria renum sinistra

System

Artery

Region

Trunk

Side

Single, on the midline

About the left renal artery

The left renal artery is one of the two large lateral branches of the abdominal aorta that carry blood to the kidneys. It arises at about the level of the disc between the first and second lumbar vertebrae, a little below the origin of the superior mesenteric artery, and leaves the aorta almost at a right angle. Together the two renal arteries carry a very large share of the heart's output, up to about a fifth to a quarter at rest, because the kidneys filter the whole blood volume many times a day.

Because the aorta lies slightly to the left of the midline, the left renal artery is shorter than the right and often a little higher. It runs laterally across the left crus of the diaphragm and psoas major to the hilum of the left kidney. In front of it on this course are the left renal vein, the splenic vein and the pancreatic body, and the inferior mesenteric vein also crosses it.

Before it reaches the hilum it divides into an anterior and a posterior division. The anterior division gives the apical, upper, middle and lower segmental arteries, which pass between the renal vein in front and the renal pelvis behind; the posterior division gives the posterior segmental artery, which passes behind the pelvis. Segmental arteries are end arteries, so each supplies its own zone of kidney with little overlap. The main artery also gives an inferior suprarenal artery and small twigs to the ureter and perirenal fat.

Variation is common. One or more accessory renal arteries, usually straight from the aorta, may enter the upper or lower pole without passing through the hilum, and these must be found before kidney surgery or transplantation. Narrowing of the artery, whether from atherosclerosis or fibromuscular dysplasia, lowers flow to the kidney, which then releases renin and raises blood pressure; it can be treated with balloon angioplasty and a stent. The vessel can also be injured in abdominal trauma.

Course and supply

Arises from

Arises from the left side of the abdominal aorta at about the L1-L2 level, just below the superior mesenteric artery.

Ends in

Divides near the hilum of the left kidney into anterior and posterior divisions that give the five segmental arteries.

Supplies

Supplies the left kidney, with an inferior suprarenal branch to the suprarenal gland and twigs to the upper ureter and perirenal fat.