The V2 secyrnent of the vertebral artery and its branches

Object. The goal of this study was to demonstrate the origins. courses. anastomoses. and target tissues of the anerial branches that arise from the V-2 segment of the vertebral artery. Methods. Ten adult cadaveric necks (20 V-2 segment specimens) were examined (magnification X 40) after injection of colored silicon. The branches at each cervical level were classified in a new system according to anatomical features and tar-et tissues-anterior, posterior, medial. and lateral. Incidence with which each branch category was observed at each cervical level was calculated. Anterior branches were observed at C-3 in all 20 V-2 segment specimens. The incidence with which the posterior branch was present at C-4 was 45%. whereas the corresponding rates at segments superior and inferior were lower. The medial V-2 segment branches were assessed in four subcategories. The anterior spinal artery was present at C-3 in all specimens, whereas the mean incidence at the C4-6 level was 46.7%. The posterior spinal artery was most frequently detected at C-3 (60%). The anterior radicular artery (RA) was present at C-5 in 50% of the specimens. whereas the posterior RA was detected at C-5 in only 35%. Lateral branches were most frequently detected at C-3. Conclusions. The authors provide detailed anatomical information about the origins. Courses. anastomoses. and target tissues of the vessels that arise from the V-2 segment. This new classification allows for better understanding of die vasculature of the C3-6 region.