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Animals : an open access journal from MDPI2026; 16(3); 482; doi: 10.3390/ani16030482

Identifying by Radiograph Grade 4 Aplasia of the Caudal Lamina Ventralis in the Equine Sixth Cervical Vertebra and Three Coinciding Morphological Variations.

Abstract: To date, radiographically identifying the bony landmarks relevant to diagnosing the complete C6 aplasia of the caudal lamina ventralis (C6 aCLV4) has not been described. Furthermore, a gross study has identified C6 aCLV4 as the main correlation between transposition of the CLV from C6 to C7, where coinciding neck pain was commonly reported. This study aimed to identify C6 aCLV4 in radiographs, where the outcome might benefit equine practitioners in isolating neck pain. Initially, the relevant bony landmarks were radiographically determined from a normal C6 by applying a lateral 30° dorsal-ventral oblique view. From here, the caudal border of the transverse process (TP) projecting from the vertebral body became the defining point of reference due to the image clearly demarcating the adjacent CLV. In C6 aCLV4 cases, the CLV is completely aplastic caudal to the TP. Twenty mixed-breed horses (13 males/7 females) aged 3-22 years radiographically demonstrated a C6 aCLV4, which was confirmed by their corresponding gross morphology. During this process three anomalous variations became apparent-in the longus colli muscle, C7 foramen transversarium, and vertebral artery. Therefore, this study demonstrates effective techniques for identifying C6 aCLV4 in horses, where the results might assist veterinarians in diagnosing neck pain while providing anatomical clarity.
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Publication Date: 2026-02-04 PubMed ID: 41681463PubMed Central: PMC12897093DOI: 10.3390/ani16030482Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Identifying complete aplasia of the caudal lamina ventralis of the sixth cervical vertebra (C6 aCLV4) through radiographs can help veterinarians diagnose neck pain in horses. This study establishes clear radiographic landmarks and notes three associated anatomical variations that occur alongside this vertebral anomaly.

Research Purpose and Background

  • The study focuses on identifying complete aplasia (Grade 4) of the caudal lamina ventralis (CLV) in the equine sixth cervical vertebra (C6).
  • C6 aCLV4 is linked to the transposition of the CLV from C6 to C7, often associated with neck pain in horses.
  • Previously, no standardized radiographic method existed to reliably detect this congenital bony defect.
  • The goal is to improve clinical diagnosis of neck pain via radiographic identification of this anomaly.

Methodology

  • Radiographs of normal equine C6 vertebrae were taken using a lateral 30° dorsal-ventral oblique view to establish relevant bony landmarks.
  • The caudal border of the transverse process (TP) was identified as the key reference point for assessing the adjacent CLV.
  • In cases of C6 aCLV4, the caudal lamina ventralis was entirely absent posterior to the TP on radiographs.
  • Twenty mixed-breed horses, aged 3 to 22 years (13 males and 7 females), were evaluated radiographically and then confirmed through gross anatomical examination.

Findings

  • The lateral 30° dorsal-ventral oblique radiographic view clearly depicted the presence or absence of the caudal lamina ventralis of C6.
  • In C6 aCLV4 cases, complete absence of the caudal lamina ventralis was evident caudal to the transverse process.
  • Gross dissection confirmed the radiographic findings, verifying the aplasia.
  • Three additional morphological variations were consistently noted in these horses with C6 aCLV4:
    • Variation in the longus colli muscle morphology.
    • Anomalous formation of the C7 foramen transversarium.
    • Variations in the vertebral artery pathway or structure.

Clinical Implications

  • The study provides veterinarians with a reliable radiographic technique to identify C6 aCLV4, aiding in differential diagnosis of equine neck pain.
  • Understanding the associated anatomical variations can help avoid misdiagnosis and better inform prognosis and therapeutic approaches.
  • This radiographic method and anatomical insights enhance clinical awareness and potentially prevent unnecessary treatments by pinpointing the source of discomfort.

Conclusion

  • The lateral 30° dorsal-ventral oblique radiograph, focusing on the caudal border of the transverse process, effectively identifies Grade 4 aplasia of the caudal lamina ventralis in C6.
  • Three coinciding anatomical variations accompany this vertebral aplasia, providing additional context for diagnosis.
  • These findings offer a practical tool for equine practitioners to correlate radiographic changes with neck pain symptoms, improving diagnostic accuracy.

Cite This Article

APA
DeClue A, Workman K, May-Davis S. (2026). Identifying by Radiograph Grade 4 Aplasia of the Caudal Lamina Ventralis in the Equine Sixth Cervical Vertebra and Three Coinciding Morphological Variations. Animals (Basel), 16(3), 482. https://doi.org/10.3390/ani16030482

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 16
Issue: 3
PII: 482

Researcher Affiliations

DeClue, Audrey
  • DeClue Equine LLC, 6955 NW 100th Street, Ocala, FL 34482, USA.
Workman, Kate
  • Rexos Incorporated (5O1c3b-Nonprofit Research Facility), 1087 Lakebay Rd., Vass, Carthage, NC 28394, USA.
  • Denali Equine PLLC, 1087 Lakebay Rd., Vass, NC 208394, USA.
May-Davis, Sharon
  • Faculty of Science, Agriculture, Business and Law, University of New England, Armidale, NSW 2350, Australia.

Conflict of Interest Statement

Author Audrey DeClue is employed by the company “DeClue Equine LLC”. Author Kate Workman is employed by the company “Denali Equine PLLC”. The authors declare no conflicts of interest.

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