Histological study of the innervation of the suspensory ligament of the forelimb of the horse.

The innervation pattern of the interosseus muscle of the forelimb was studied in two ponies and two horses. The nerves of the suspensory ligament were studied histologically after neurectomy of the ulnar and median nerve branches proximal to the carpal joint. The results demonstrated that the interosseus muscle is innervated by the deep branch of the lateral palmar nerve which emerges at the level of the midcarpal region and contains fibres from the ulnar and the median nerve. These findings provide evidence that an ulnar nerve block proximal to the accessory bone would fail to anaesthetise the entire suspensory ligament.