Laryngeal paralysis

Laryngeal paralysis in animals is a condition in which the nerves and muscles that control the movements of one or both arytenoid cartilages of the larynx cease to function, and instead of opening during inspiration and closing during swallowing, the arytenoids remain stationary in a somewhat neutral position. Specifically, the muscle that causes abduction of the arytenoid cartilage, the cricoarytenoideus dorsalis muscle, ceases to function. This leads to inadequate ventilation during exercise and during thermoregulatory panting as well as incomplete protection of the airway during swallowing. Affected animals thus have reduced tolerance for exercise and heat and an increased risk of aspiration pneumonia. Laryngeal paralysis is fairly common in large breed dogs and is rarely found in cats. It can also occur in horses where it is referred to as roaring, roarer's syndrome, or medically as laryngeal hemiplegia or recurrent laryngeal neuropathy (RLN). Laryngeal paralysis can be unilateral or bilateral depending upon dysfunction of one or both arytenoid cartilages.