system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, RESULTS. Meshes: Animals, Epiglottis, Female, Glossopharyngeal Nerve, Horses, Hypoglossal Nerve, Male, Nerve Block, Orchiectomy, Palate, Soft, Pharynx, Physical Exertion, Pressure, Respiration, Trachea.
user
Does effects of bilateral hypoglossal and glossopharyngeal nerve block on epiglottic and soft palate position in exercising horses? Context: To determine the effect of bilateral hypoglossal and and glossopharyngeal nerve block on epiglottic and soft palate position and tracheal and pharyngeal pressures in exercising horses. 5 Standardbreds. Tracheal and pharyngeal pressures were measured in 5 Standardbreds exercising at the speed at which the horses achieved 50, 75, and 100% of maximal heart rate after bilateral hypoglossal and glossopharyngeal nerve block and without nerve block. Nerve block was achieved by injection of 1 to 2 ml of 2% mepivicaine hydrochloride between the glossopharyngeal and hypoglossal nerves, as they coursed through the medial compartment of the diverticulum of the auditory tube (guttural pouch), using videoendoscopic guidance and an injection apparatus. Compared with control values, peak inspiratory tracheal pressure was significantly (P = 0.02) more negative, and peak pharyngeal inspiratory pressure was less negative (P = 0.004) after bilateral hypoglossal and glossopharyngeal nerve block. Respiratory frequency was significantly (P = 0.024) lower after nerve block, compared with control values. The epiglottis was unstable and retroflexed through the rima glottis during inspiration after bilateral hypoglossal and glossopharyngeal nerve block. Despite loss of contact between the epiglottis and the caudal free margin of the soft palate, dorsal displacement of the soft palate did not occur.
assistant
Loss of contact of the epiglottis with the soft palate did not affect soft palate position, suggesting that when the soft palate is normal, the epiglottis does not function as a support, holding the soft palate in a ventral position. Therefore, epiglottic dysfunction is not solely responsible for intermittent dorsal displacement of the soft palate in horses, and neuromuscular dysfunction involving the hyoepiglotticus muscle, geniohyoideus muscle, or the hypoglossal nerve may cause epiglottic retroflexion in horses. Final Decision: yes