Abstract

Abstract Object Knowledge of the quantitative anatomy of the C2 spine is essential to safely perform anterior plate-screw fixation of the C2 spine. Injury to the spinal cord during drill or screw placement is the most feared complication of this procedure. Therefore, proper screw length is the most important issue for safety of vertebral body screw placement. Obviously, understanding the safety distance between the entry point of screw insertion and the posterior cortex of the vertebral body is essential. In this study, we analyze the anatomy of the C2 body relevant to C2 anterior plate-screw fixation. Materials and Methods Eighty-six dried C2 spines were evaluated directly for this study. Measurements were made on the C2 body width and midsagittal anteroposterior (AP) depth as well as AP parasagittal depth 5 mm lateral to the midline on the inferior endplates, in addition to on the middle body. Measurements also were made on AP parasagittal vertebral depth with both medial and lateral inclination of 10 degrees, with respect to the parasagittal plane of the vertebral body. Results The ideal maximum screw length and trajectory was found to be AP medial parasagittal depth of inferior surface of the C2 body [Right: 13.7±1.4 mm (11.0-17.9), Left: 13.6±1.5 mm (10.7-17.8)]. Conclusions We report the measurements of the vertebral body of the C2. We think these measurements provide guidelines for conducting operations on the anterior C2 spine, and enhance the confidence interval of the surgeon. Key Words: anterior plate, screw, corpus, C2, axis.