CONCLUSIONS
Horses affected by epiglottic compression in the current manuscript presented primarily with signs of abnormal respiratory noise and/or poor performance, as well as one horse presenting after physically collapsing in a race. The pathophysiology of this disorder likely involves inward compression of the epiglottis from the hyoid apparatus, in the area of thyrohyoid bone and thyroid cartilage articulation, as the larynx and hyoid apparatus advances rostrally through a progressively narrowing intermandibular space during poll flexion. This is supported by the inward movement of the lateral nasopharyngeal walls seen visually during poll flexion in all cases, combined with current knowledge of how the laryngohyoid apparatus changes in position during poll flexion. The present treatment recommendation is to limit the degree of poll flexion by use of tack modifications in affected horses. Further studies are necessary to confirm the proposed pathogenesis of this URT disorder and objectively define how this disorder impacts upper airway dynamics in exercising horses.