Authors: May-Davis Sharon, Eckelbarger Pamela Blades, Dzingle Diane, Saber Elle
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Morphological Dependencies in Equine Complex Vertebral Malformation Equine complex vertebral malformation (ECVM) continues to challenge practitioners managing cervical pathology, yet the specific anatomical relationships driving the condition remain incompletely understood. May-Davis and colleagues examined 85 C6 vertebrae and their corresponding C7 specimens to investigate whether absent or hypoplastic ventral tubercles on C6 predictably influence abnormal bone formation on C7. The researchers identified a striking pattern: when C6 demonstrated complete absence of the caudal ventral tubercle (grade 4) alongside partial absence of the cranial ventral tubercle (grades 1–3), 44 of 85 paired C7 vertebrae (approximately 52%) showed transposition of C6's ventral process onto C7's ventral surface, with roughly two-thirds of these transpositions replicating an ectopic transverse foramen. Importantly, the laterality was consistent—left-sided C6 defects correlated with left-sided C7 transpositions, with the same pattern observed on the right and in bilateral cases. These findings suggest a mechanistic dependency rather than random association, potentially helping practitioners interpret radiographic presentations of caudal cervical pain by recognising which morphological grades of C6 pathology warrant heightened scrutiny of corresponding C7 changes and their contribution to clinical signs.
Read the full abstract on PubMed
Practical Takeaways
- •When examining horses presenting with caudal cervical pain, radiographers should look specifically for the characteristic morphological relationship between C6 and C7 vertebrae, particularly absent ventral tubercles and their transposition patterns on C7
- •Sidedness matters—if you identify absent ventral processes on one side of C6, expect corresponding transposition on the same side of C7, which can help guide diagnosis and treatment planning
- •Understanding that these morphological variations often co-occur together can improve diagnostic accuracy and help differentiate ECVM from other causes of cervical pain in your cases
Key Findings
- •In 85 C6 specimens, absent caudal ventral tubercle (aCVT) grades 1-4 often extended cranially to create absent cranial ventral tubercle (aCrVT) grades 1-3
- •44/85 corresponding C7 vertebrae demonstrated complete or incomplete transposition of the C6 ventral process, with 30/44 replicating a transverse foramen
- •Strong statistical dependency existed between C6 grade 4 aCVTs with grades 1-3 aCrVTs and C7 transpositions with replicated transverse foramen
- •Sidedness was demonstrated with left-sided absent C6 associated with left-sided C7 transposition, and bilateral cases showed consistent patterns