The renal arteries arise at the level of the intervertebral disc between the L1 and L2 vertebrae. The longer right renal artery passes posterior to the
inferior vena cava. Typically, each artery divides close to the hilum
into five segmental arteries that are end arteries (i.e., they do not
anastomose significantly with other segmental arteries, so that the area
supplied by each segmental artery is an independent, surgically
resectable unit or renal segment). Segmental arteries are distributed to
the renal segments as follows:
• The superior (apical) segment is
supplied by the superior (apical) segmental artery; the anterosuperior
and anteroinferior segments are supplied by the anterosuperior segmental
and anteroinferior segmental arteries; and the inferior segment is
supplied by the inferior segmental artery. These arteries originate from
the anterior branch of the renal artery.
• The posterior segmental
artery, which originates from a continuation of the posterior branch of
the renal artery, supplies the posterior segment of the kidney.
Multiple renal arteries are common and usually
enter the hilum of the kidney. Extrahilar renal arteries from the renal
artery or aorta may enter the external surface of the kidney, commonly
at their poles.