Morphological variability of the renal artery branching pattern: a brief review and an anatomical study

The segmental branches of the renal artery vary in number and origin. The 1998, Terminologia Anatomica homologates two branches of the renal artery (anterior, posterior) and five segmental arteries: four from the anterior branch and one from the posterior one. The purpose of this study is to evaluate the renal artery branching pattern, the number and origin of the segmental arteries, as well as to review data from similar studies. The study material consisted of 60 formalin-fixed adult kidneys. Dissections and microdissections were performed on the renal arteries and their branches. The branching of the renal artery was prehilar in 81.67% of cases, hilar in 10% and intra-sinusal in 8.33%. The number branches varied as follows: two branches in 42 cases (70%), three branches in 14 cases (23.33%) and four branches in four cases (6.67%). We subsequently analyzed the origin of the segmental arteries and found that in 53% of the cases the segmental arteries arose independently from the renal artery's branches, while in 47% of the cases they derived from common trunks of type I (85%) or II (15%). Type I trunks are those that originate directly from the main renal artery. They divide either into 2-3 segmental branches, or into just 1-2 branches and a smaller trunk (type II). The type II trunks further divide into 2-3 other segmental branches. These common trunks must be taken into account to avoid confusion with the segmental arteries. Knowledge of these variations is useful not only morphologically, but also clinically.