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Objective— To assess the effect of head position on relative position of the larynx and hyoid apparatus in horses with palatal dysfunction, and to define a standard position for radiographic assessment of laryngeal tie-forward.

Study Design— Prospective clinical study.

Animals— Adult horses (n=9) with palatal dysfunction.

Methods— Left lateral radiographs of the larynx were obtained pre and postoperatively for 3 different head positions (flexed=90°; neutral=100°; extended=115°). Distance between thyrohyoid bone and thyroid cartilage was measured. Data were analyzed to investigate differences between head positions, and to compare differences between pre- and postoperative measurements.

Results— Head position had a significant effect on relative position of the larynx and hyoid apparatus preoperatively. There was no significant difference in postoperative measurements of the 3 head positions. A significant difference between pre- and postoperative measurements was found with the head in the neutral or extended position whereas there were no significant differences between pre- and postoperative measurements using the flexed position.

Conclusions— Head position affects the relationship between the hyoid apparatus and larynx preoperatively, with greatest distance occurring when the head is extended. In a flexed position, it is not possible to ascertain whether laryngeal position has changed postoperatively.

Clinical Relevance— A standardized head position is necessary when assessing the laryngeal tie-forward procedure radiographically. An extended head position is most useful for this assessment.