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.