Each renal artery, as well as its segmental branches near the hilum, also supplies numerous small branches to the perinephric fat, renal fascia, renal capsule, renal pelvis, and ureter.

Segmental Branches. Near the hilum, each renal artery splits into a small posterior and a larger anterior branch. These major branches, in turn, give rise to segmental arteries, each destined for one of the kidney’s wedge-shaped vascular segments. In most kidneys, three to five segmental arteries supply the parenchyma in a characteristic pattern.

Most of the time, the posterior branch continues as the single posterior segmental artery, which runs posterior to the renal pelvis. The anterior branch, in contrast, courses farther into the sinus before dividing into two to four anterior segmental arteries, which enter the parenchyma between the veins and the renal pelvis.

Each segmental artery supplies a vascular renal segment, a distinct portion of the kidney named for the segmental artery it receives. In kidneys with five segmental vessels, a characteristic pattern has been identified. The superior and inferior segments, located at the poles, receive the superior and inferior segmental arteries from the anterior branch of the renal artery. On the anterior surface, the area between the poles is divided into the anterior superior and anterior inferior segments; these receive the anterior superior and anterior inferior segmental arteries from the anterior branch of the renal artery. On the posterior surface, a single posterior segment lies between the polar segments and receives the posterior segmental artery. The terminology is easily adjusted for kidneys with fewer than five segmental arteries/vascular segments via comparison with the five segment pattern. The superior or posterior segmental arteries/segments are most likely to be absent.