Laryngeal hemiplegia is a problem that can leave your horse breathless. It damages the function of one of the arytenoids [ah-RIT-en-oids], structures that open to let air into the windpipe, resulting in a smaller working airway and a horse left gasping for air.
Common signs of laryngeal hemiplegia are a roaring sound when the horse breathes in, labored breathing and difficulty performing exercise. Some roarers show more signs at rest, while others suffer most with exercise.
At the University of Florida’s Large Animal Hospital, endoscopy is used to pinpoint the problem. A tube is passed to magnify and illuminate the opening and closing of the windpipe, first while the horse is standing and again during a trot or canter on a treadmill. Surgeons can then perform the procedure best suited to help the equine athlete return to full form.