Prevalence of Anatomical Variation of the Sixth Cervical Vertebra and Association with Vertebral Canal Stenosis and Articular Process Osteoarthritis in the Horse.

This research examines the unique structures of the sixth cervical vertebra (C6) in horses which, due to a protrusion known as ventral lamina, can vary in form. The study specifically sought to determine the prevalence of such variation in a large horse sample, as well as its clinical significance. Findings indicate that horses with anomalous C6 vertebrae have higher odds of experiencing cervical pain.

Study Overview

• This observational, retrospective study sought to describe the various forms of the sixth cervical vertebra (C6) in horses.
• It used radiographic studies of the cervical vertebrae of 100 horses, recording factors such as the horses’ breed and sex, clinical history, shape of C6 ventral lamina, articular process osteoarthritis and vertebral canal stenosis.

Key Findings

• Out of the 100 horses studied, 24 exhibited morphologic variations in their C6 vertebrae—nine had a symmetric absence of the ventral lamina, and fifteen had an asymmetric absence.
• This irregularity was more prevalent in Warmblood horses with 19 out of 55 Warmblood horses in the study population having this anomaly.
• The study found no correlation between these C6 abnormalities and sex or articular process osteoarthritis. But, horses with unusual C6 vertebrae had a likelihood of a sagittal ratio of less than 0.5 at C6, indicting possible vertebral canal stenosis.
• Interestingly, anomalous C6 vertebrae correlated with a higher likelihood of cervical pain, shedding light on its clinical relevance.

Conclusion and Future Scope

• The authors suggest that these C6 variations could be signs of other developmental abnormalities such as vertebral canal stenosis and impact the biomechanics of the region.
• These findings hint at the clinical significance of C6 anomalies, warranting consideration in equine healthcare and treatment decisions.
• The authors advocate for future prospective studies to further validate this theory and investigate its potential implications.