Description of the Anatomical Landmarks for Measuring Intravertebral and Intervertebral Sagittal Diameter Ratios on Equine Cervical Radiographs

 

Introduction: The objective of this study is to describe the anatomical landmarks for the floor of the vertebral canal to be used when measuring the intravertebral and intervertebral minimum sagittal diameter ratios on cervical spinal radiographs of horses. Our hypothesis is that on lateral cervical radiographs, the most ventrally located, craniocaudally oriented mineral opaque line seen on the craniodorsal aspect of the vertebral bodies (floor of the vertebral canal) represents the mid sagittal aspect of the vertebral canal.

Materials and Methods: The cervical spine of an adult horse was obtained postmortem. A radiographic marker was sequentially placed at three discreet locations along the craniodorsal aspect of the C4 vertebral body including the left and right osseous ridges abaxial to midline, and on sagittal midline. The cervical vertebrae were then manually realigned and lateral radiographs of the C3–C5 vertebrae were subsequently made. Computed tomographic images of the cervical spine were obtained to depict the anatomy of the vertebral canal.

Results: When the marker was placed on the abaxial osseous ridges and midsagittal aspect of the C4 vertebral body, it demarcated the more dorsally located and more ventrally located, craniocaudally oriented mineral opaque lines at the craniodorsal aspect of the vertebral body, respectively.

Discussion/Conclusion: This study describes the radiographic appearance of the anatomical landmark for the floor of the vertebral used to measure the intravertebral and intervertebral minimum sagittal diameter ratios for evaluation of equine cervical vertebra malformation.

Acknowledgment: There was no proprietary interest or funding provided for this project. The authors thank Bobbie Davis for helping with radiographs.