Variations of testicular vessels are more common than supposed. The testicular artery varies because of abnormal regression of the lateral mesonephric arteries in the fetus, whereas variations in the testicular vein are due to abnormalities in the involution of the intersubcardinal anastomosis. Such variations are usually found incidentally during surgical procedures around the renal pedicle and they often lead to complications. Several authors have attempted to classify them. However, these attempts have not been comprehensive. Therefore, the aim of this study is to provide a simple yet comprehensive classification of variations of the testicular vessels. The PubMed database was searched using keywords pertaining to the testicular vessels. The results were subjected to the Anatomical Quality Assessment (AQUA) tool analysis and were screened for appropriateness for inclusion in this study. The screening procedure yielded 31 original articles, 83 case reports, and 1 review article. Both testicular arterial and venous variations were more common on the left side (20.73% and 24.61%) than the right (12.69% and 18.4%, respectively). We classified the testicular arteries on the basis of their number (N), site of origin (O), and course (C). Similarly, the testicular veins were classified on the basis of their number (N) and site of drainage (D). The proposed classification facilitates identification, understanding, and reporting of variations of the testicular vessels by radiologists. It will also help surgeons to enhance the quality of their treatment. Clin. Anat. 31:854-869, 2018. © 2018 Wiley Periodicals, Inc.
