Fig. 2.

This cervical spine demonstrated opposite characteristics in each transverse foramen. On the left side, FA, PTA and LMA are larger than those of the right side. Therefore, insertion of pedicle screws would be difficult, and lateral mass screws should be selected. Furthermore, longer sizes can be selected. In contrast, when the values of the right side are smaller than those of the left side, insertion of pedicle screws is easier. a FA (Rt). b FA (Lt). c PTA (Rt). d PTA (Lt). e LMA (Rt). f LMA (Lt)