Tortuosity of Vertebral Artery between the Atlas and the Axis

Kang, Ho Suck; Kim, Ji Won; Choi, Byoung Young; Cho, Byung Pil; Hwang, Tae Sun; Koh, Ki Seok

Abstract

This study was performed to investigate the anatomical features of vertebral artery between the atlas and the axis. For this, we examined four angles (angle I, angle II, angle III and angle IV) to identify tortuosity of vertebral artery and diameter between the atlas and the axis. Materials used in this study were 93 vertebral arteries obtained from 48 adult Korean cadavers (34 males, 14 females) ranging from 18 to 90 years in age. On the anterior view, the vertebral artery relatively ascended vertically from C6 to the axis and then laterally passed through the foramen transversarium (FT) of the axis. The average of this angle I was 83.3 degree. The average of the right and left sides of this angle I were 84.7 degree and 82.0 degree, respectively. The average of angle I (95.4 degree) in female was larger than that (80.5 degree) of male. The artery passed through the FT of the axis turned to the superior direction. The average of this angle II was 95.9 degree. The right and left sides of the angle II were 97.8 degree and 93.8 degree, respectively. As the angle I, the average of angle II (110.6 degree) in female was larger than that of angle II (93.1 degree) in male. On the lateral view, the vertebral artery relatively ascended vertically from C6 to the axis and then posteriorly passed through the FT of the axis. The average of this angle III was 71.3 degree. The artery passed through the FT of the axis turned to the superior direction. The average of this angle IV was 87.3 degree. In angle III and angle IV, the average of angle in female were larger than that of male. These results show that female has greater tortuosity than male. The average diameter of the vertebral artery was 3.7 mm and the average diameter of right and left are 3.5 mm and 4.0 mm, respectively. In 76% of the total, left vertebral artery diameter was larger than that of the right.