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.

Controversy exists with respect to the innervation of the suspensory ligament (SL) in the fore limb of the horse. It is uncertain whether this structure is exclusively innervated by branches of the ulnar nerve or also to some extent by median nerve branches. Ground Reaction Forces (GRF) were determined in horses before and after the induction of a tendonitis in the lateral branch of the SL by the injection of collagenase, and before and after a high palmar and an ulnar block respectively. The high palmar block succeeded in bringing all GRF variables back to their original values which the ulnar block did not. It is concluded that the SL is innervated by branches of both the ulnar and the median nerves, with the median nerve being relatively more important for the distal part of the SL.