Axial anatomical evaluation of the posterior atlantoaxial transarticular screw fixation

Objective: To provide morphological basis for the posterior atlantoixal transarticular screw fixation. Methods:The clinical significant data were measured on 100 dry axis specimens.Results:The pedicle width of 96.5% specimen was larger than 4.5 mm. In 11.5% specimens, the internal height of the lateral mass was smaller than 2.1 mm. The internal height of the pedicle was smaller than 4.5 mm in 20.6 % of all specimens, while 8.1% was at the right side and 12.5% was at the left side.The internal height of the pedicle was smaller than 4.5 mm in 15.7% male specimens and 10% female specimens.The axis of the screw fixation was found to lie at 39.2°±* 5.04° in the medical direction and 5. 79°± 2. 45° in the superior direction. Conclusion: 21. 5% Chinese are unsuitable for posterior atlantoaxial transarticular screw fixation.