COMPUTED TOMOGRAPHIC ANATOMY OF THE CANINE LUMBOSACRAL SPINE

The lumbosacral spine (L5-S3) was examined by high resolution computed tomography (CT) in five canine cadaver specimens and one anesthetized dog using 5mm thick transverse slices at 5mm intervals. In each dog, anatomic features observed on CT images were confirmed by comparison w ith corresponding 5mm thick anatomic transverse sections and section r adiographs. CT anatomic features visualized in all dogs included the v ertebral bodies, pedicles, laminae, articular processes, spinous proce sses, transverse processes, mammillary processes, basivertebral venous canals, vertebral foramina, intervertebral foramina, sacral wings, me dian sacral crest, intermediate sacral crests, lateral sacral crests, articular process joints, sacroiliac joints, internal vertebral venous plexus, epidural fat, thecal sac, L5-S3 nerve roots, and spinal nerve s. Spinal ganglia, yellow ligaments, and portions of the intervertebra l discs were visible in some dogs. The spinal cord, intrathecal nerve roots, dorsal and ventral longitudinal ligaments, spinal arteries, and radicular vessels were not distinguishable. Accessory processes were identified on the caudal L5 pedicles in most dogs, an observation that differed from descriptions in standard anatomy texts. Previously unde scribed osseous grooves, termed ''lateral recesses,'' were identified in the caudal L7 vertebral foramen of all dogs.