Soft palate angle and basihyoid depth increase with tongue size and with
body condition score in horses.
Abstract
Background: Obesity has been associated with human obstructive
sleep apnoea and canine brachycephalic obstructive airway syndrome. To
the authors’ knowledge the effect of body condition score (BCS) on
structures of the oropharynx , nasopharynx and upper airway of the horse
has not been investigated. Objectives: To investigate the
effect of BCS on tongue area and height, soft palate angle and basihyoid
depth in the horse. Study Design: Retrospective, analytical,
cross-sectional. Methods: Computed tomographic (CT) images of
the head of 44 horses were assessed. DICOM viewing software was used to
measure head length, basihyoid-skin depth, soft palate angle (SPA),
midline tongue area and dorsoventral height (DVH) of the tongue in two
locations. BCS were assigned at the time of CT examinations.
Results: Increased BCS led to an increased mean SPA (mean
difference=2.56 ˚ ; P=0.019) and increased median basihyoid depth
(mean difference=0.246cm; P=0.006). Following adjustments made
for the effect of head length on tongue measures, significant
correlation was identified between SPA and tongue area (Spearman’s
r=0.544; P=0.007); SPA and DVH of the tongue at the level of the
hard palate (Spearman’s r=0.562; P=0.004) and SPA and DVH of the
tongue at the lingual process of the basihyoid bone (Spearman’s r=0.690;
P<0.001). No significant correlation was identified
between variables with sex or age of horses. Conclusions:
Increased BCS increases SPA and basihyoid bone depth. Increases in
tongue size measurements increase SPA. Results from this study warrant
further investigation into the clinical significance of the effects of
BCS on the upper airways of the horse.