Location of the vertebral artery in the cervicothoracic junction.

Eight sectioned specimens and 8 cadavers were used to evaluate the location of the vertebral artery in the cervicothoracic junction. The results of the measurements showed that there was no significant difference between either sides at the C7-T1 junction in terms of all distances taken. The mean width of the vertebral artery was 2.9 mm at the levels of the C-7 and T-1. The sagittal distance between the vertebral artery and the posterior cortex was 16.8+/-3.0 mm at the C7 and 21.7+/-2.8 mm at T-1. The coronal distance between the vertebral artery and the midline of the vertebra was 17.5+/-1.8 mm at the C7 and 22.3+/-2.9 mm at the T-1. The mean angle between the line connecting the lateral border of the vertebral artery with the posterior midway of the lateral mass and the parasagittal line at C-7 was 14.1+/-6.1 degrees. The mean angle of the vertebral artery with respect to the midline was 22.8+/-6.4 degrees. This study suggests that the vertebral artery has closer anatomic relationship to the C-7 lateral mass. Care should be taken to avoid injury to the vertebral artery if lateral mass screw fixation at the C-7 is intended.