Effects of Flexion and Extension on the Diameter of the Caudal Cervical Vertebral Canal in Dogs

Abstract

Objective: To quantify changes in the diameter of the vertebral canal with flexion and extension in the cervical vertebral column. Study Design: Cadaveric biomechanical study. Sample Population: Cadaveric canine cervical vertebral column (n=16 dogs). Methods: All vertebral columns were evaluated with MRI. Group 1 consisted of 8 normal vertebral columns. Group 2 included 8 vertebral columns with intervertebral disc degeneration. Flexion, extension, compression, and tension were applied to the caudal cervical region (C4-5, C5-6, C6-7). Sagittal vertebral canal diameters (VCD) were obtained by measuring the distance between the ventral and dorsal aspects of vertebral canal. Results: No differences were seen between groups, thus the results are for both groups. Comparison of VCD between flexion and extension with no load revealed a difference of 2.2mm (28.9%; P