OBJECTIVE : To establish sagittal area and length reference values and ratios between
apparently normal canine cervical vertebrae and intervertebral disks using magnetic
SAMPLE : Retrospective evaluation of cervical vertebral column magnetic resonance
imaging studies of 44 dogs representing 5 different breeds (Labrador Retriever, n = 10;
French Bulldog, n = 10; Great Dane, n = 9; Chihuahua, n = 10; Dachshund, n = 5).
PROCEDURES : Mid-sagittalmeasurements of vertebral body and disk areaswere obtained
from C3 through C7 vertebrae and C2/C3 through C6/C7 intervertebral disks. Disk to
vertebra area ratios were calculated and compared among dog breeds. Additionally,
sagittal vertebral body and disk length measurements were obtained and disk to vertebra
length ratios calculated. Inter and intra observer variability was assessed.
RESULTS : There were significant differences for disk to vertebral body area and length
ratios between evaluated dog breeds and cervical vertebral locations (p < 0.001). Mean
area ratio of Chihuahuas was significantly larger than all other breeds, while results from
Dachshunds were only significantly different than Chihuahuas and Labrador Retrievers.
Mean area ratios were statistically different between the cranial and caudal cervical
vertebral locations. Regarding length ratios, results from Chihuahuas were significantly
different than all breeds except Dachshunds. Mean length ratios were statistically
different between all cervical locations, except C2/C3 compared to C3/C4. Intra- and
interobserver variability was very good to excellent.
CONCLUSION AND CLINICAL RELEVANCE : There are significant differences in area and length ratios between dog breeds. Differences also exist in area and length ratios between
the cranial and caudal cervical vertebral column. These differences may play a role in the
development of vertebral column diseases including intervertebral disk disease.