OBJECTIVE: to evaluate de morphometry of the pars of the second cervical vertebra, assess the variations existent and predict its safety for the placement of screws through a posterior cervical approach. METHODS: 58 vertebrae were obtained for anatomic study (116 pars of C2) and measured the height and width of the pars, besides the length of the axis-pedicle, width and length of the pedicle, sagittal and medial angulations. All measurements were separated as to their right and left sides, completed the calculation of media, variation, standard deviation and compared to previous studies. RESULTS: the medium width of the pars of C2 was 9,5 mm, the height, 9,5 mm, without significant difference between right and left sides. The medium length of the pedicle was 10.5 mm and the medium measurement found for the length axis-pedicle was of 24.9 mm and the width of the pedicle was of 2.8 mm. The sagittal angulation found was of 19.6º and the horizontal was of 28.5º. CONCLUSIONS: this study demonstrates the viability of positioning screws in the pars of C2 in a Caucasian population, emphasizing, however, the great anatomic variability found in the referred measurements.
Cervical Vertebrae; Spine; Bone screws; Spinal fusion; Humans
