1Alpha-hydroxyvitamin D3 prevents the decrease of bone mineral density in lactating beagles

We assessed the change of bone mineral density (BMD) in lactating beagles with dual energy X-ray absorptiometry (DXA) and the preventive effect of 1alpha-hydroxyvitamin D3 (1alpha(OH)D3) on the BMD. Beagles, two to five years old, were used for detecting the time course change of BMD. Since the coefficient of variation (CV(%)) on detecting lumber vertebral (L2-L4) and tibial BMD by DXA was about 0.5%, DXA was useful to detect the change of BMD in beagles. There was a marked decrease in vertebral BMD during lactational period in the control group. The BMD levels after weaning were found to reverse to the initial level at mating. The same tendency was observed in tibial BMD as vertebral BMD, though the BMD changes were not marked. Beagles were administered at a dose of 0.1 microg/kg of 1alpha(OH)D3 three times in a week, and it was found to suppress the decrease in vertebral BMD during the breast feeding period. Also, the administration of 1alpha(OH)D3 promoted the prevention of decreased BMD during lactation both in vertebrae and tibiae. Significant effects of 1alpha(OH)D3 administration on tibial BMD were not observed. No adverse effects, such as hypercalcemia and hypercalciuria, were observed during the experimental period. Therefore, DXA was useful for detecting the changes of BMD in lactating beagles and the change of BMD was marked in lumber vertebrae, which are rich in trabecular bone. The preventive effect of 1alpha(OH)D3 on the decrease of BMD during the lactation period was observed in beagles.     

Osteology and radiology of the vertebral column in the white-eared opossum (Didelphis albiventris)

The white-eared opossum present a higher roadkill number in Brazil, and the vertebral column is often affected when some type of trauma occurs. Thus, this study describes the osteology and radiology of the vertebral column in white-eared opossum to serve as a basis for support in the veterinary clinical care, since the casuistry of care of this marsupial has increased every year. Radiographs of the cervical (C), thoracic (T), lumbar (L), sacral (S) and caudal (Cd) segments of the vertebral column were taken in thirty-five white-eared opossums (Didelphis albiventris). Furthermore, ten opossums without evident vertebral acquired or congenital abnormalities at the radiographic study were selected for anatomical study. Osteology was correlated with the radiographic images. The use of radiographs allowed the identification of congenital and acquired vertebral changes, as well as the identification of anatomical structures, their distribution and morphology and the number of vertebrae. The vertebral formula varied in the white-eared opossum. In 27 of 35 white-eared opossums (77.2%) with normal vertebral morphology, three vertebral formulas were observed: C7/T13/L6/S2 (62.9%), C7/T13/L5/S2 (5.7%) and C7/T13/L7/S2 (8.6%). Most of the specimens presented 27 caudal vertebrae. The anticlinal vertebra was identified as T10 in 77.2% and T11 in 22.8% of opossums. Cervical block vertebra was observed in two animals and sacrocaudal block vertebra in one animal. The haemal arches could be seen from Cd3–Cd4 in 80% and Cd2–Cd3 in 20% of opossums. The white-eared opossum showed a slender vertebral column with a relatively short thoracic region, a relatively long lumbar region and a highly flexible lumbosacral transition, suggesting that this animal is a fast-running and agile opossum. Therefore, these findings may serve as a basis for further research and support the veterinary clinical care, since the casuistry of care for this marsupial has increased every year.     

Comparison of the access window created by hemilaminectomy and mini-hemilaminectomy in the thoracolumbar vertebral canal using computed tomography

Hemilaminectomy and mini-hemilaminectomy were performed on opposite sides of the spine at T11–T12, T13-L1, and L2–L3 in 11 canine cadavers in order to report differences in the access provided to the thoracolumbar vertebral canal. Measurements of the vertebral canal height, defect height, and dorsal and ventral remnants of the vertebral arch were obtained after computed tomography. A median of 7% to 20% of the vertebral canal height was not removed dorsally after mini-hemilaminectomy compared to 1% to 2% in hemilaminectomy. Thirteen to 25% of the vertebral canal height was left ventrally in mini-hemilaminectomy and 11% to 27% in hemilaminectomy. Potential for a restricted exposure of thoracolumbar lesions should be considered if lesions are located in the ventral 11% to 27% vertebral canal height when performing either procedure or in the dorsal 7% to 20% of the canal height when performing a mini-hemilaminectomy.     

Vertebral mineral density measured by dual-energy X-ray absorptiometry (DEXA) in a group of healthy Italian boxer dogs

We studied the feasibility of using dual-energy X-ray absorptiometry (DEXA) to obtain reference bone density values in relation to age, gender and body weight in growing and young adult Italian boxer dogs. The study was performed on eight animals (three males and five females) at 7, 12 and 18 months of age. Animals were carefully examined and blood samples were collected from each dog to detect any sign of metabolic and/or endocrine disease. Each subject underwent radiographs to evaluate growth of the spine and hip. One female was not considered in the statistical model because of the development of grade 4 spondylosis deformans during the study period. All animals were serially scanned using DEXA; the region of interest was the whole spine T12-L2, while the subregions of interest were the four vertebrae (T12-T13-L1-L2) within the scanned spine. Statistical analysis was performed separately for each region of interest. Age had the strongest relationship with bone density (P < 0.001). Gender effect on spinal mineral density was not significant while vertebral site effect was highly significant. Average bone mineral density (BMD) +/- SD for the whole spine trait was 0.862 +/- 0.108 g/cm2 while average BMD +/- SD for subregions of interest ranged from 0.836 +/- 0.141 g/cm2 for T12 to 0.928 +/- 0.119 g/cm2 for L2. Estimated reference BMD values at 7, 12 and 18 months of age for each vertebral site in males and females are provided.     

A PROPOSED RADIOGRAPHIC CLASSIFICATION SCHEME FOR CONGENITAL THORACIC VERTEBRAL MALFORMATIONS IN BRACHYCEPHALIC “SCREW‐TAILED” DOG BREEDS

Congenital vertebral malformations are common in brachycephalic “screw‐tailed” dog breeds such as French bulldogs, English bulldogs, Boston terriers, and pugs. The aim of this retrospective study was to determine whether a radiographic classification scheme developed for use in humans would be feasible for use in these dog breeds. Inclusion criteria were hospital admission between September 2009 and April 2013, neurologic examination findings available, diagnostic quality lateral and ventro‐dorsal digital radiographs of the thoracic vertebral column, and at least one congenital vertebral malformation. Radiographs were retrieved and interpreted by two observers who were unaware of neurologic status. Vertebral malformations were classified based on a classification scheme modified from a previous human study and a consensus of both observers. Twenty‐eight dogs met inclusion criteria (12 with neurologic deficits, 16 with no neurologic deficits). Congenital vertebral malformations affected 85/362 (23.5%) of thoracic vertebrae. Vertebral body formation defects were the most common (butterfly vertebrae 6.6%, ventral wedge‐shaped vertebrae 5.5%, dorsal hemivertebrae 0.8%, and dorso‐lateral hemivertebrae 0.5%). No lateral hemivertebrae or lateral wedge‐shaped vertebrae were identified. The T7 vertebra was the most commonly affected (11/28 dogs), followed by T8 (8/28 dogs) and T12 (8/28 dogs). The number and type of vertebral malformations differed between groups (P = 0.01). Based on MRI, dorsal, and dorso‐lateral hemivertebrae were the cause of spinal cord compression in 5/12 (41.6%) of dogs with neurologic deficits. Findings indicated that a modified human radiographic classification system of vertebral malformations is feasible for use in future studies of brachycephalic “screw‐tailed” dogs.     

北京黑猪NR6A1、VSX2、VRTN、LTBP2基因多态性与脊椎数及胴体性状的关联分析

旨在研究NR6A1、VSX2、VRTN、LTBP2基因在北京黑猪群体中基因的多态性与脊椎数和胴体性状(胴体长、胴体直长、胴体斜长及胴体重)的关联。本研究提取410头(210±7)日龄健康北京黑猪耳组织DNA,通过PCR技术和Sanger测序技术对4个基因外显子区进行基因分型,计算变异位点基因型频率以及等位基因频率的分布,并与脊椎数和胴体性状进行关联分析。结果表明,在VSX2、VRTN、LTBP2三个基因中共筛选到15个SNPs,其中包含1个CDS区的同义突变和14个3'UTR突变。使用Duncan's多重检验统计分析发现,VSX2基因中CDS区的1个突变c.536 G＞A与脊椎数关联显著(P＜0.05)。VRTN中3'UTR区共4个突变与性状关联显著(P＜0.05),其中c.2598 A＞G和c.2607 G＞T与脊椎数、胴体长、胴体直长及胴体斜长关联显著,c.3087 G＞C只与胴体斜长关联显著,c.3094 A＞G与脊椎数及胴体斜长关联显著(P＜0.05)。LTBP2上6个3'UTR突变位点(c.7158 A＞G、c.6869 C＞T、c.6319 G＞C、c.6246 G＞T、c.6170 A＞G、c.6079 G＞T)与脊椎数关联显著(P＜0.05),但与胴体性状关联不显著。综上所述,VSX2、VRTN、LTBP2基因中共有10个SNPs与脊椎数性状关联显著(P＜0.05),仅VRTN基因中4个SNPs与胴体性状关联显著(P＜0.05)。这些关联显著的SNPs可以作为北京黑猪脊椎数及胴体性状变异的候选基因功能位点。     

Confirmed and presumptive cervical vertebral compressive myelopathy in older horses: a retrospective study (1992-2004)

BACKGROUND: Cervical vertebral compressive myelopathy (CVCM) is a common cause of myelopathy in horses aged 6 months to 4 years. Little information is available regarding the types of lesions, treatment, and outcomes in horses with CVCM that are > or =4 years old. ANIMALS: Twenty-two affected horses (10 with a confirmed diagnosis of CVCM and 12 presumptive cases) and 210 contemporaneous control horses. METHODS: Horses > or =4 years old that were diagnosed with CVCM between January 1992 and January 2004 were identified from medical records at Texas A&M University and the University of Florida. Data analyzed included history, signalment, neurologic examination findings, lesion location, treatment, and outcome. Signalment was also recorded in a population of contemporaneous controls. RESULTS: Horses identified had a median age of 8.4 years, and there was a greater percentage of male horses among the cases than among the controls. The most common breeds represented were warmblood (n=6) and quarter horse (n=5) types; warmbloods were significantly (P < .05) overrepresented relative to control horses. The caudal cervical vertebral column was the most common site of CVCM lesions, and the C5-C6 (4/9) and C6-C7 (3/9) articulations were most often identified as abnormal via myelography. The most common lesions seen with radiography and myelography were articular process osteophytes. Of the 22 affected horses, 8 were euthanized and a diagnosis of CVCM was confirmed by necropsy for all; 5 of 8 of these horses had spinal cord compression caused, entirely or in part, by articular process osteophytes. Medical management was the therapy chosen in all horses, and administration of corticosteroids and nonsteroidal anti-inflammatory drugs resulted in improvement in the greatest number of horses. CONCLUSIONS AND CLINICAL IMPORTANCE: CVCM should be a differential diagnosis in older horses with cervical myelopathy. Articular process osteophytes are the most frequently identified cause of spinal cord compression in this group. Male horses and horses of warmblood or Tennessee Walking Horse breeds may be predisposed to this condition.     

Facet joint geometry and intervertebral disk degeneration in the L5-S1 region of the vertebral column in German Shepherd dogs

OBJECTIVE: To evaluate the possible association between facet joint geometry and intervertebral disk degeneration in German Shepherd Dogs. ANIMALS: 25 German Shepherd Dogs and 11 control dogs of similar body weight and condition. PROCEDURE: Facet joint angles in the caudal portion of the lumbar region of the vertebral column (L5-S1) were measured by use of computed tomography, and the intervertebral discs were evaluated microscopically. The relationship between facet joint geometry and disk degeneration was evaluated by use of statistical methods. RESULTS: German Shepherd Dogs had significantly more facet joint tropism than control dogs, but an association with disk degeneration was not found. However, German Shepherd Dogs had a different facet joint conformation, with more sagittally oriented facet joints at L5-L6 and L6-L7 and a larger angle difference between the lumbar and lumbosacral facet joints, compared with control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: A large difference between facet joint angles at L6-L7 and L7-S1 in German Shepherd Dogs may be associated with the frequent occurrence of lumbosacral disk degeneration in this breed.     

Distribution of new methylene blue injected into the lumbosacral epidural space in cats

OBJECTIVE: To determine the effects of injection volume and vertebral anatomy on the spread of new methylene blue (NMB) injected into the lumbosacral epidural space in cats. STUDY DESIGN: Prospective experimental study. SAMPLE POPULATION: Sixteen cats. METHODS: Cats were randomly assigned to four groups and received from 0.1 to 0.4 mL kg(-1) of 0.12% NMB in 0.9% saline. Injection was made into the lumbosacral epidural space using a dorsal approach with the cats in sternal recumbency. The extent of cranial migration of the dye as indicated by the staining of epidural fat and dura mater was measured. RESULTS: The mean +/- SD (range) number of stained vertebrae in the 0.3 and 0.4 mL kg(-1) groups, were 11.5 +/- 1.5 (T7-T11) and 12.4 +/- 1.8 (T6-T10), respectively. This was significantly greater than the number in the 0.1 and 0.2 mL kg(-1) groups, 4.3 +/- 0.6 (L3-L4) and 6.0 +/- 0.7 (L1-L2) vertebrae, respectively (p < 0.001). Linear regression analysis showed that the volume injected correlated significantly with the number of stained vertebrae (R2 = 0.83, p < 0.001). In the dorsal and lateral aspect of the spinal cord, NMB solution distributed between epidural fat and dura mater. Migration under the spinal cord occurred along the two longitudinal epidural veins. CONCLUSIONS AND CLINICAL RELEVANCE: The larger the volume of solution injected into the lumbosacral epidural space in cats, the greater the spread.     

Chordoma of the thoracic vertebrae in a Bengal tiger (Panthera tigris tigris)

A 19-year-old female Bengal tiger (Panthera tigris tigris) was presented with hind limb weakness, ataxia and respiratory distress. Computed tomography revealed a mass between the left side of the T7 vertebra and the base of the left 7th rib. The tiger then died, and necropsy was performed. Grossly, the vertebral mass was 6 × 5.7 × 3 cm, and invaded the adjacent vertebral bone and compressed the T7 spinal cord. Histologically, the mass was composed of large, clear, vacuolated and polygonal cells with osteochondral matrix. Cellular and nuclear atypia were moderate. The vacuolated cells stained positively for cytokeratin and vimentin and negatively for S-100. Based on these findings, the present case was diagnosed as a vertebral chordoma; the first report in a tiger.     

Intradural extramedullary granular cell tumour in a cat

A 7-year-old domestic shorthair cat was evaluated for progressive paraparesis, inability to jump, a paralysed tail and inability to void the bladder. Neurologic examination was consistent with a L4-S3 localisation. Survey radiographs of the lumbar vertebral column revealed L4-L7 vertebral body remodelling. A pre-contrast T1-weighted hyperintense, diffusely enhancing intradural lesion extending from L4 to S1 vertebral bodies was detected by MRI. Large, mesenchymal, round-to-polygonal cells arranged in nests or sheets were found on histologic examination at post mortem. These cells were characterised by abundant intracytoplasmic PAS-positive, diastase-resistant granules and positive immunoexpression of vimentin, S-100, neuron-specific enolase and desmin. This is the first report of a spinal granular cell tumour in a cat.     

北京黑猪HoxB簇基因多态性与脊椎数及胴体性状的关联分析

旨在对北京黑猪HoxB簇9个基因(HoxB1-7、9和13)的多态性与脊椎数和胴体性状(胴体长、胴体直长、胴体斜长及胴体重)进行关联分析。本研究提取251头220日龄的健康北京黑猪耳组织DNA,对HoxB簇的9个基因通过引物设计、聚合酶链式反应(PCR)技术、Sanger测序技术等对SNPs进行基因分型，并计算变异位点基因型频率以及等位基因频率分布，并与脊椎数和胴体性状进行关联分析。结果，本试验共筛选到4个基因共12个非编码区的(UTR)SNPs,包括HoxB2基因的1个5′UTR突变、HoxB5基因的2个3′UTR突变、HoxB9基因的2个3′UTR突变以及HoxB13基因的7个3′UTR突变。将12个SNPs分别与脊椎数和胴体性状使用Duncan′s多重检验统计分析发现，HoxB2基因的1个5′UTR突变(c.40 C>T)、HoxB5基因的2个3′UTR突变(c.1766 A>G、c.1767 A>G)均与性状关联不显著(P>0.05);而HoxB9基因中的1个3′UTR突变(c.2743 C>T)与胴体性状关联显著(P<0.05),HoxB1...     

Prevalence of diseases of the spinal cord of cats

A retrospective review of records of 205 cats with histologically confirmed disease of the spinal cord was performed to identify the prevalence of disease in this nonrandomly selected population of cats. Clinical records were reviewed, and age, duration of neurologic illness, and clinical and histopathologic findings in cats with spinal cord disease were abstracted. Disease processes were classified into 7 categories and 23 groups. The most common diseases affecting the spinal cord of cats were feline infectious peritonitis (FIP), lymphosarcoma (LSA), and neoplasia of the vertebral column secondarily affecting the spinal cord. Information on age, onset and duration of clinical signs, and lesion localization at the postmortem examination in cats belonging to the 7 categories of disease were analyzed to create a practical list of differential diagnoses. Cats were also subcategorized into 3 groups based on their age at death. FIP was the most common disease of cats younger than 2 years of age. LSA and vertebral column neoplasia were the most common diseases affecting cats between 2 and 8 years of age. Vertebral column neoplasia was the most common disease affecting cats older than 8 years of age. Results of this histopathologic study showed that FIP and LSA were the most common disease processes affecting the spinal cord of cats. However, at least 21 other groups of diseases and their relative prevalence were identified.     

Distribution of neurons supplying the porcine mammary gland

The distribution of neurons projecting to the mammary gland was investigated by using the retrograde tracing method in juvenile pigs (n = 12). Fluorescent retrograde tracer Fast Blue (FB) was injected into the nipple (n = 3) or parenchyma (n = 3) of the second, right thoracic mamma or into the nipple (n = 3) and parenchyma (n = 3) of the last, right abdominal mamma. FB-positive (FB+) mammary gland-projecting neurons were found in some right dorsal root ganglia (DRG) and sympathetic chain ganglia (SChG) only. After injection of the tracer into the second, right thoracic mamma, FB+ neurons were observed in Th9-Th12 DRG but most of them were located in Th11 and Th12 ganglia. As concerns SChG, FB+ neurons were found in Th1-Th4, Th7-Th14 and L1-L4 ganglia. The vast majority of them were located in Th10 and Th11 SChG, which appeared to be the main sources of efferent innervation of this mamma. Neurons projecting to the last right abdominal mamma were found in L1-L3 DRG and L1-L4 SChG but most of them were located in L1-L2 ganglia and L1-L2 ganglia, respectively. This study for the first time has disclosed the localization of neurons supplying the mammary gland in larger domestic animal species, the pig, by using the retrograde tracing method.     

Daily controlled physiotherapy increases survival time in dogs with suspected degenerative myelopathy

The purposes of the study reported here were to evaluate the signalment and clinical presentation in 50 dogs with degenerative myelopathy, to evaluate whether mean survival time was significantly affected by various means of physiotherapy performed in 22 dogs, and to determine whether neurologic status, anatomic localization, or age at onset had an influence on survival time in dogs that received physiotherapy. We found a significant (P < .05) breed predisposition for the German Shepherd Dog, Kuvasz, Hovawart, and Bernese Mountain Dog. Mean age at diagnosis was 9.1 years, and both sexes were affected equally. The anatomic localization of the lesion was spinal cord segment T3-L3 in 56% (n = 28) and L3-S3 in 44% (n = 22) of the dogs. Animals that received intensive (n = 9) physiotherapy had longer (P < .05) survival time (mean 255 days), compared with that for animals with moderate (n = 6; mean 130 days) or no (n = 7; mean 55 days) physiotherapy. In addition, our results indicate that affected dogs which received physiotherapy remained ambulatory longer than did animals that did not receive physical treatment.     

Diffuse idiopathic skeletal hyperostosis of the spine in a nine‐year‐old cat

A nine‐year‐old intact female domestic shorthair cat was evaluated for paraparesis, ataxia and severe spinal hyperaesthesia. Neurological examination indicated a T3‐L3 spinal cord segment lesion. Computed tomography of the thoracolumbar and lumbosacral vertebral column was performed. This showed contiguous smooth new bone formation ventral and lateral to the vertebrae extending from the cranial thoracic area to the lumbosacral junction and appearing similar to canine diffuse idiopathic skeletal hyperostosis. There was also marked dorsolateral stenosis of the vertebral canal at the level of T4‐T5 because of degenerative changes of the facet joints. To the authors’ knowledge, this is the first published report of feline diffuse idiopathic skeletal hyperostosis.     

The effect of induced hindlimb lameness on thoracolumbar kinematics during treadmill locomotion

REASON FOR PERFORMING STUDY: There are no detailed studies describing a relationship between hindlimb lameness and altered motion of the back. OBJECTIVES: To quantify the effect of induced subtle hindlimb lameness on thoracolumbar kinematics in the horse. METHODS: Kinematics of 6 riding horses were measured during walk and trot on a treadmill before and during application of pressure on the sole of the left hindlimb using a well-established sole pressure model. Reflective markers were located at anatomical landmarks on the limbs, back, head and neck for kinematic recordings. Ground reaction forces (GRF) in individual limbs were calculated from kinematics to detect changes in loading of the limbs. RESULTS: When pressure on the sole of the hindlimb was present, horses were judged as lame (grade 2 on the AAEP scale 1-5) by an experienced clinician. No significant unloading of this limb was found in the group of horses (unloading was observed in 4 animals, but was not detectable in the other 2), but statistically significant effects on back kinematics were detected. The overall flexion-extension (FE) range of motion (ROM) of the vertebral column was increased at walk, especially in the thoracic segments. Axial rotation (AR) ROM of the pelvis was also increased. At trot, the FE ROM was decreased only in the segment L3-L5-S3. During the stance phase of the lame limb, the segment T6-T10-T13 was more flexed and the neck was lowered at both gaits; the thoracolumbar segments were more extended at walk and trot. There were no significant changes in the stride length or protraction-retraction angles in any of the limbs. CONCLUSIONS: Subtle hindlimb lameness provoked slight but detectable changes in thoracolumbar kinematics. The subtle lameness induced in this study resulted in hyperextension and increased ROM of the thoracolumbar back, but also in decreased ROM of the lumbosacral segment and rotational motion changes of the pelvis. POTENTIAL RELEVANCE: Even subtle lameness can result in changes in back kinematics, which emphasises the intricate link between limb function and thoracolumbar motion. It may be surmised that, when chronically present, subtle lameness induces back dysfunction.     

辣根过氧化物酶标记法研究鸡直肠传入神经元的分布

采用辣根过氧化物酶（HRP）逆行追踪法研究了鸡直肠感觉传入神经元的分布，证明鸡直肠脊神经感觉传入神经元集中分布于双侧T5～LS3和LS7～LSl2脊神经节，峰值位于T7和LS10脊神经节；LS7-LS12区段脊神经节内标记细胞明显多于T5～LS3区段脊神经节内的标记细胞；标记细胞为椭圆形和圆形。     

RADIOGRAPHIC DIAGNOSIS: CARTILAGINOUS EXOSTOSES IN A DOG

A 6 month-old dog was examined for progressive paraparesis. On physical examination bony malformations were palpated over the cranial lumbar vertebral bodies and on the left metatarsal bone. Neuroanatomic lesion localization for the paraparesis was a T3-L3 spinal cord lesion. Radiographs confirmed bony masses at L1-L2 and on the left 3rd metatarsal bone. Magnetic resonance imaging was performed from T3-L3. Severe spinal cord compression was identified at L1-L2. Surgical decompression and biopsy confirmed the mass to be cartilaginous exostoses. This paper is an example of cartilaginous exostoses imaged with MR.     

EVALUATION OF TRADITIONAL AND NOVEL RADIOGRAPHIC VERTEBRAL RATIOS IN GREAT DANES WITH VERSUS WITHOUT CERVICAL SPONDYLOMYELOPATHY

Great Danes are predisposed to osseous‐associated cervical spondylomyelopathy (Wobbler syndrome). The first aim of this prospective study was to compare values measured using previously published intravertebral and intervertebral ratio methods and a novel ventrodorsal ratio method in radiographs of clinically normal and affected Great Danes. The second aim was to determine whether these ratios could be used as predictors of sites of spinal cord compression based on magnetic resonance imaging (MRI). Thirty dogs (15 normal, 15 affected) were prospectively enrolled. Lateral and ventrodorsal radiographs were obtained and six measurements were recorded from C3‐T1. For each vertebral location, intravertebral ratios and intervertebral ratios were calculated from lateral views, and the ratio of the distance between the articular process joints vs. vertebral body width (novel ventrodorsal ratio) was calculated from ventrodorsal views. Values for these three ratios were compared, by vertebral location and dog group. Intravertebral and intervertebral ratios did not differ between dog groups. The ventrodorsal ratio was significantly smaller in affected Great Danes at C5–6 (P = 0.005) and C6–7 (P < 0.001). The ventrodorsal ratio was significantly associated with MRI presence of spinal cord compression. For each 0.1 unit increase in this ratio value, there was a 65% decrease in the odds of spinal cord compression being present at that site, independent of vertebral location (P = 0.002). Findings from this study supported use of the novel ventrodorsal ratio as an initial radiographic screening method for Great Danes with suspected cervical spondylomyelopathy.