Anatomical variation of the spinous and transverse processes in the caudal cervical vertebrae and the first thoracic vertebra in horses.
Authors: Santinelli I, Beccati F, Arcelli R, Pepe M
Journal: Equine veterinary journal
Summary
# Editorial Summary Anatomical variation in the caudal cervical spine is poorly documented in the equine literature, yet understanding normal morphological diversity is essential for accurate radiographic interpretation and avoiding false diagnoses of pathology. Santinelli and colleagues retrospectively evaluated radiographs from 270 horses to characterise anatomical variants of the 6th and 7th cervical vertebrae and first thoracic vertebra (T1), testing for breed and sex associations using Chi-square analysis. The researchers identified three distinct variants in the C7 spinous process and two in the T1 spinous process; notably, the presence or absence of the C7 spinous process showed breed-related variation, whilst transposition of the C6 ventral process demonstrated sex-related differences, with morphological features of T1 correlating significantly with both C7 configuration and C6 ventral process presentation. For practitioners reporting on cervical radiographs, these findings highlight the critical importance of recognising breed-specific and sex-influenced anatomical variation as normal rather than pathological, thereby reducing the risk of overinterpreting incidental bony changes as new bone formation associated with cervical articular disease or other conditions. This knowledge base should inform clinical decision-making when evaluating horses with cervical dysfunction, ensuring that radiographic findings are interpreted within the context of each animal's individual anatomical presentation.
Read the full abstract on PubMed
Practical Takeaways
- •Familiarize yourself with normal anatomical variants in C6-T1 on radiographs to avoid misinterpreting them as signs of periarticular new bone formation or pathology
- •Expect breed and sex-related differences in cervical spine morphology when evaluating radiographs—use breed-specific reference data when available
- •These variants appear to be benign anatomical differences rather than indicators of disease, so their presence alone should not influence clinical decision-making without other supporting evidence of pathology
Key Findings
- •Three morphological variants identified in the spinous process of C7 and two variants in the first thoracic vertebra spinous process
- •Presence of C7 spinous process variant was associated with breed; transposition of C6 ventral process was associated with sex
- •Shape of first thoracic vertebra spinous process correlated with C7 spinous process shape and C6 ventral process transposition
- •Anatomical variants are common radiographically in the caudal cervical region and must be distinguished from pathological new bone formation