Surgical Anatomical Landmarks of the Thoracolumbar Vertebral Column on Magnetic Resonance Imaging in Dogs

Abstract

Magnetic resonance imaging (MRI) in veterinary medicine profoundly improved spinal cord disease investigation in canine patients. We aimed to further describe the anatomical landmarks of the thoracolumbar junction in sagittal MRI sequences. MRI studies from 90 dogs were reviewed retrospectively, representing a broad cross section of breeds and body weights. The ratio of the distance from the dorsal aspect of the vertebral canal to the dorsal aspect of the transverse process or rib articulation relative to the length of L2 vertebra was determined for T12, T13, L1 and L2 vertebrae. A statistically significant difference was noted with the transverse processes being more ventrally located than the cranial fovea costalis. The lumbar transverse processes and rib articulations dramatically varied in shape, being oval or round, respectively. The sagittal image at the level of the lateral margin of the articular facet joint proved to be the most consistent for review of these structures.

Diagnostic Imaging in Intervertebral Disc Disease

“…In one study the celiac artery and mesenteric arteries were ventral to the first lumbar vertebra in 71 and 97% of dogs, respectively (78). In another study where they were under the body of L1 in only 59.6% of dogs, with an additional 11.2 and 20.2% under the intervertebral discs T13-L1 and L1-2, respectively (79). As such, their location is variable and they do not represent an accurate vertebral landmark.…”

“…The dorsal plane can be very useful in these instances since the ribs and transverse processes can be easily identified. In cases where dorsal images are not available, sagittal (parasagittal) images can be used (79). Rib articulations and lumbar transverse processes can be easily distinguished based on different shapes and heights relative to the vertebral canal (79).…”

“…In cases where dorsal images are not available, sagittal (parasagittal) images can be used (79). Rib articulations and lumbar transverse processes can be easily distinguished based on different shapes and heights relative to the vertebral canal (79). The transverse plane is essential for circumferential assessment of spinal cord compression and lateralization.…”