The role of B-mode ultrasonography in the musculoskeletal anatomical evaluation of the cervical region of the dog spine

This study characterized the normal musculoskeletal anatomy of the cervical segment of the spine of dogs by means of B-mode ultrasonography. The objective was to establish the role of B-mode ultrasonography for the anatomical evaluation of the cervical spine segment in dogs, by comparing the ultrasonographic findings with images by computed tomography and magnetic resonance imaging. The ultrasound examination, in transverse and median sagittal sections, allowed to identify a part of the epaxial cervical musculature, the bone surface of the cervical vertebrae and parts of the spinal cord through restricted areas with natural acoustic windows, such as between the atlanto-occipital joint, axis and atlas, and axis and the third cervical vertebra. The images, on transverse and sagittal planes, by low-field magnetic resonance imaging, were superior for the anatomical identification of the structures, due to higher contrast between the different tissues in this modality. Computed tomography showed superiority for bone detailing when compared with ultrasonography. As for magnetic resonance imaging, in addition to the muscles and cervical vertebrae, it is possible to identify the cerebrospinal fluid and differentiate between the nucleus pulposus and annulus fibrosus of the intervertebral discs. Although not the scope of this study, with knowledge of the ultrasonographic anatomy of this region, it is believed that some lesions can be identified, yet in a limited manner, when compared with the information obtained mainly with magnetic resonance imaging. The ultrasound examination presented lower morphology diagnostic value compared with the other modalities.