The larynx is a tube of cartilages that form the throat and contain the vocal cords. Laryngeal inflammation manifests as poor performance and noise on inspiration during exercise. Horses with this condition are called “roarers”. The most common cause of roaring (also known as stridor) is weakness or paralysis of the arytenoid cartilage, typically on the left side. Because the arytenoid cartilage does not move normally, it impairs normal airflow, which is of particular concern during activity.