The effect of the high palmar nerve block and the ulnar nerve block on lameness provoked by a collagenase-induced tendonitis of the lateral branch of the suspensory ligament.

The study analyzes nerve block impact on lameness caused by a specific tendon injury in the suspensory ligament of a horse’s leg. It concludes that the suspensory ligament is innervated by both ulnar and median nerves, and a high palmar block is more effective than an ulnar block in restoring original Ground Reaction Forces.

Objective and Background

• The main objective of this research is to identify the innervation of the suspensory ligament and investigate the influence of high palmar and ulnar nerve blocks on lameness caused by collagenase-induced tendonitis.
• The innervation of the suspensory ligament in horses has long been a topic of debate, with uncertainty surrounding whether the ligament is exclusively supplied by the ulnar nerve or partially also by the median nerve.

Methodology

• Tendonitis was artificially induced in horses through collagenase injection into the lateral branch of the suspensory ligament.
• Ground Reaction Forces (GRF) – forces exerted by the ground on a body in contact with it – were measured before and after inducing tendonitis, and also post high palmar and ulnar nerve blocks.

Results

• The high palmar nerve block was found to be effective in restoring all measured Ground Reaction Forces to their initial values before the tendonitis was induced.
• The ulnar nerve block, in contrast, did not achieve this restoration, indicating it did not completely alleviate the induced lameness.

Conclusion

• The study concludes that the suspensory ligament in horses is innervated by branches of both the ulnar and the median nerves.
• More crucially, it points out that the median nerve plays a relatively larger role in the distal part of the ligament.’