Characterization of the Caudal Ventral Tubercle in the Sixth Cervical Vertebra in Modern Equus ferus caballus.
Abstract: This study examined the anomalous variations of the ventral process of C6 in modern E. ferus caballus. The aim was to provide an incremental grading protocol measuring the absence of the caudal ventral tubercle (CVT) in this ventral process. The findings revealed the most prevalent absent CVT (aCVT) was left unilateral (n = 35), with bilateral (n = 29) and right unilateral (n = 12). Grading was determined in equal increments of absence 1/4, 2/4, 3/4, with 4/4 representing a complete aCVT in 56/76, with a significance of p = 0.0013. This also applied to bilateral specimens. In those C6 osseous specimens displaying a 4/4 grade aCVT, 41/56 had a partial absence of the caudal aspect of the cranial ventral tubercle (CrVT). Here, grading absent CrVTs (aCrVT) followed similarly to aCVTs, though 4/4 was not observed. The significance between 4/4 grade aCVTs and the presentation of an aCrVT was left p = 0.00001 and right p = 0.00018. In bilateral specimens, C6 morphologically resembled C5, implying a homeotic transformation that limited the attachment sites for the cranial and thoracal longus colli muscle. This potentially diminishes function and caudal cervical stability. Therefore, it is recommended that further studies examine the morphological extent of this equine complex vertebral malformation (ECVM) as well as its interrelationships and genetic code/blueprint.
Publication Date: 2023-07-22 PubMed ID: 37508161PubMed Central: PMC10376820DOI: 10.3390/ani13142384Google Scholar: Lookup
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Summary
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This research paper focused on a study that scrutinized anomalies in the sixth cervical vertebra (C6) of the modern domestic horse – Equus ferus caballus. Primarily, the study sought to understand the gradation process of the absence of caudal ventral tubercle (CVT) in the C6 ventral process and its potential implications on stability and function of the equine neck.
Examination of Variations in the Ventral Process
- The researchers conducted an assessment of the irregular variations found in the ventral or forward-facing part of the C6 vertebra.
- Their main objective was to devise a methodical increment process to quantify the absence of a small protrusion (CVT) found particularly in the ventral process of C6.
- Study outcomes indicated that the most generally encountered absence of the CVT was unilateral on the left side, followed by both sides, and least on the right side.
Grading Protocol and Findings
- The researchers used a grading protocol to quantify the absence of the CVT with increments of 1/4, 2/4, 3/4, with 4/4 signifying a complete absence.
- This grading system proved to be significant as it revealed that a total absence of CVT occurred 56 times out of 76.
- Such grading protocol also proved to be relevant for samples exhibiting bilateral anomalies.
Morphological Resemblance with C5 and Functional Implications
- Interestingly, when the C6 vertebra specimens exhibited a complete 4/4 grade absence of the CVT, they morphologically resembled the fifth cervical vertebra (C5).
- This resemblance suggests a possible homeotic transformation, an architectural shift from C6 to C5, that decreases attachment sites for specific neck muscles.
- This potential shift could be linked to diminished function and stability of the caudal or ‘tail-end’ of the horse’s neck.
Recommendations and Implications for Future Studies
- The findings of this study pointed to the need for further research investigations to better understand the extent of this potential misshaping of the equine vertebra (ECVM).
- Future research needs to further explore the interrelationships and the genetic blueprint responsible for the ECVM as such abnormalities can have significant health and performance implications for the Equus ferus caballus species.
Cite This Article
APA
May-Davis S, Dzingle D, Saber E, Blades Eckelbarger P.
(2023).
Characterization of the Caudal Ventral Tubercle in the Sixth Cervical Vertebra in Modern Equus ferus caballus.
Animals (Basel), 13(14).
https://doi.org/10.3390/ani13142384 Publication
Researcher Affiliations
- Canine and Equine Research Group, University of New England, Armidale, NSW 2351, Australia.
- Equus Soma-Equine Osteology and Anatomy Learning Center, Aiken, SC 29805, USA.
- Biological Data Science Institute, Australian National University, Canberra, ACT 2601, Australia.
- Equus Soma-Equine Osteology and Anatomy Learning Center, Aiken, SC 29805, USA.
Conflict of Interest Statement
The authors declare no conflict of interest.
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Citations
This article has been cited 7 times.- DeClue A, Workman K, May-Davis S. Identifying by Radiograph Grade 4 Aplasia of the Caudal Lamina Ventralis in the Equine Sixth Cervical Vertebra and Three Coinciding Morphological Variations. Animals (Basel) 2026 Feb 4;16(3).
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- May-Davis S, Eckelbarger PB, Dzingle D, Saber E. Characterization and Association of the Missing Ventral Tubercle(s) from the Sixth Cervical Vertebra and Transpositions on the Ventral Surface of the Seventh Cervical Vertebra in Modern Equus ferus caballus. Animals (Basel) 2024 Jun 20;14(12).
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