Neck pain and stiffness, thoracic limb lameness, and neurological deficits are often overlooked yet significant contributors to poor performance in horses, particularly Warmbloods. The study by Dyson, Zheng, and Aleman offers a comprehensive exploration of caudal neck pathology, shedding light on its clinical features and implications for equine health.

Background and Objectives

The caudal cervical vertebrae play a pivotal role in a horse’s biomechanical and neurological function. Pathologies in this region can manifest as pain, stiffness, proprioceptive deficits, or lameness. While radiological abnormalities in this area are commonly observed, their clinical relevance remains debated. This study aimed to identify specific phenotypic traits associated with caudal neck pathology in Warmblood horses and compare their frequency with healthy controls. The ultimate goal was to enhance diagnostic accuracy for better management of affected horses.

Study Design and Methods

A case-control study design was employed, involving 223 Warmblood horses (96 cases and 127 controls). The cases exhibited symptoms such as neck-related thoracic limb lameness, neck pain, or proprioceptive deficits. Controls were free of neck-related issues, with lameness attributed to other causes.

Comprehensive orthopedic and neurological evaluations were conducted, including static and dynamic assessments, palpation, gait analysis, and electromyography (EMG). Horses were also evaluated for lateral and vertical neck flexion, posture, and response to palpation.

Key Findings: Clinical Markers of Caudal Neck Pathology

• Static Examination InsightsHorses with caudal neck pathology exhibited:

1. 1. Focal muscle atrophy (47.9%) and poor overall neck muscle development (39.6%).
   2. Pain, hypoesthesia, or hyperesthesia in the caudal cervical region upon palpation.
   3. Abnormal grazing posture, with thoracic limbs spread sideways or front-to-back, was a distinguishing marker.

• Dynamic Examination ObservationsCases showed a higher frequency of:
• • 1. Stiff neck movement and asymmetrical lateral flexion.
    2. Head and neck tilting during lunging or ridden exercise.
    3. Thoracic limb stumbling and hopping-type lameness unique to caudal cervical lesions.Interestingly, thoracic limb lameness often became more apparent during ridden exercises, particularly with rein tension. This underscores the importance of ridden assessments in diagnosing neck-related lameness.

• Neurological Deficits and EMG Findings
  Nearly half of the cases (49%) were classified as neurological, with symptoms ranging from mild to severe proprioceptive deficits. EMG confirmed nerve root or spinal cord involvement, aligning with clinical observations of stumbling, muscle weakness, and altered gait.
• Work Discipline Trends
  Show jumpers were disproportionately affected (42.7% of cases), potentially due to the biomechanical demands of landing forces and neck extension during jumps. Dressage horses, conversely, were underrepresented among cases.

Implications for Diagnosis and Management

The study highlights several actionable insights for equine practitioners:

1. Thorough Clinical Evaluation
   Systematic assessments, including detailed palpation and observation during dynamic exercises, are essential. Neck pain and stiffness, combined with specific postural and gait abnormalities, strongly indicate caudal cervical pathology.
2. Role of Electromyography (EMG)
   EMG proved invaluable in pinpointing neurologic dysfunction and localizing affected spinal cord segments. While not definitive in every case, it provides critical evidence for diagnosing cervical nerve compression or spinal disease.
3. Ridden Assessments as Diagnostic Tools
   Many neck-related abnormalities only became apparent during ridden exercise. This underscores the importance of incorporating ridden assessments into routine evaluations for performance issues.
4. Discipline-Specific Considerations
   The higher prevalence of neck pathology in show jumpers may reflect occupational hazards, emphasizing the need for preventive care in this discipline. For dressage horses, potential effects of hyperflexion on cervical health warrant further study.

Limitations and Future Directions

The study’s focus on Warmbloods limits its generalizability to other breeds. Additionally, the reliance on subjective assessments introduces potential bias, though the standardized approach minimized variability. Future research could explore advanced imaging modalities and long-term outcomes of surgical or therapeutic interventions.

Conclusion: Enhancing Equine Welfare Through Better Diagnostics

This study significantly advances our understanding of caudal neck pathology in Warmblood horses. By identifying key phenotypic traits and their frequency, it equips veterinarians with practical tools for more accurate diagnoses. As equine sports continue to evolve, addressing neck-related issues proactively will be crucial in promoting both performance and welfare.

Dyson S, Zheng S, Aleman M. Primary phenotypic features associated with caudal neck pathology in warmblood horses. J Vet Intern Med. 2024;38(4):2380-2390. doi:10.1111/jvim.17125