The sixth cervical vertebra (C6) has unique morphology due to a ventral extension from the transverse process known as the ventral lamina. Little information was found regarding the prevalence and clinical relevance of morphologic variations. Aims of this observational, retrospective study were to characterize C6 morphologic variations in a large sample of horses. Cervical radiographic studies of 100 horses were retrieved. Data recorded were signalment, clinical history, morphology of the C6 ventral lamina, presence of articular process osteoarthritis, and presence of static vertebral canal stenosis. Morphologic variations were found in C6 vertebrae for 24/100 horses, with symmetric absence of the ventral lamina in nine horses and asymmetric absence in 15. Anomalous C6 vertebrae were more common in Warmbloods, with 19/55 Warmbloods in the population being affected (P = 0.006). No association was found with sex. There was no significant difference in the mean of the intravertebral sagittal ratios between horses with normal or anomalous C6 vertebrae; however there was a significantly greater proportion of horses with anomalous C6 vertebrae that had an intravertebral sagittal ratio of less than 0.5 at C6 (P = 0.047). There was no association between the morphology of C6 and articular process osteoarthritis. Anomalous C6 vertebrae in our population were associated with a higher likelihood of cervical pain (P = 0.013). Authors propose that morphologic variations in the C6 ventral laminae could be linked to other developmental abnormalities such as vertebral canal stenosis, might affect regional biomechanics and should therefore be considered clinically relevant in horses. Future, controlled prospective studies are needed to test this theory.

Background Cervical osteoarthritis (OA) has been documented as a potential source of pain and poor performance in sport horses. Objectives To assess the prevalence of cervical OA in a population of Warmblood jumpers and its correlation with age, level of performance, neck pain and mobility. Study design Descriptive observational study. Methods Warmblood jumpers free of lameness or neurological disorders were selected. Cervical pain and range of motion of the neck were subjectively assessed. Left to right lateral views were taken at C3‐C4, C4‐C5, C5‐C6 and C6‐C7. The presence of OA at the cervical articular process joints (APJs) was evaluated and graded as absent, mild or moderate to severe by three board‐certified radiologists. The agreement between radiologists and the potential associations between OA grades with age and other variables were statistically assessed (P < .05). Results One hundred and four horses were included [median age = 10 years (range 6‐18 years)]. Agreement between radiologists varied from fair to substantial (Kappa‐weighted 0.37‐0.61). The C6‐C7 APJ was most commonly affected by OA with only 32.7% of APJ considered free of radiographic abnormalities at this location versus 60.5% at C5‐C6, 81.7% at C4‐C5 and 84.6% at C3‐C4. Horses competing in higher level classes (peak of performance) had significantly higher OA grades at C6‐C7 (P = .013). There was no association between age, age when started jumping, neck pain and neck range of motion with the presence of OA on radiographs. Main limitations Open enrolment and lack of orthogonal views. Conclusions This study showed that, although there is a range of interpretation of radiographic findings of the APJ, OA of the caudal cervical region is not rare in performing sound Warmblood jumpers. This suggests that OA in the caudal cervical region may be of low clinical significance.

CASE DESCRIPTION A 4-year-old sexually intact male pet guinea pig (Cavia porcellus) was evaluated for a routine wellness examination. CLINICAL FINDINGS During physical examination, a small mass was palpated in the cranial aspect of the abdomen. Abdominal radiographic and ultrasonographic findings were suggestive of a gastric mass. Cytologic evaluation of a fine-needle aspirate of the mass was indicative of spindle cell proliferation most consistent with a sarcoma. TREATMENT AND OUTCOME The patient was anesthetized, and an exploratory laparotomy and partial gastrectomy were performed to resect the gastric mass. Histologic and immunohistochemical examinations of the mass revealed that it was a gastric leiomyoma. The patient recovered from surgery without complications. No evidence of mass recurrence was observed during an abdominal ultrasonographic examination performed approximately 19 months after surgery. CLINICAL RELEVANCE To our knowledge, this was the first report of the clinical diagnosis and successful surgical treatment of a gastric neoplasm in a guinea pig. Gastric leiomyomas are not uncommon in guinea pigs, and although benign, they can cause clinical signs if they become large enough to impair gastric function. Gastrointestinal surgery should be considered as a treatment option for guinea pigs with similar gastric neoplasms.

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