Figure 4

Radiographic pharyngeal diameter as a function of the head and neck positions (flexed, neutral, extended). There was a significant difference in the pharyngeal diameters between the flexed head and neck position and the neutral and extended head and neck positions. There was no significant difference between the pharyngeal diameters measured in the neutral and extended head and neck positions. There were no significant differences in pharyngeal diameter at each head and neck position between horses with and without respiratory noise during exercise. The boxes define the upper and lower quartiles with the medians marked by the horizontal lines. The whiskers indicate the minimum and maximum values (n = 35).