These conditions are not detectable at rest; they occur secondary to the negative inspiratory pressure in the larynx during deep breathing at exercise.
Vocal fold collapse results in axial deviation of the vocal fold within the rima glottidis. This can occur with laryngeal hemiplegia or after laryngoplasty, ventriculectomy or tie-forward procedures. Bilateral ventriculocordectomy should be performed.
Axial deviation of the aryepiglottic folds occurs when the aryepiglottic fold is drawn axially into the rima glottidis. The condition is commonly bilateral and can be seen in horses with recurrent laryngeal neuropathy or dorsal displacement of the soft palate (DDSP). Treatment is partial resection of the left and right aryepiglottic folds adjacent to the rima glottidis.
Epiglottic retroversion results in caudal retroversion of the epiglottis into the rima glottidis. Treatment is limited, but is aimed at stabilization of the thyroepiglottic articulation.