This study aimed to objectively assess the influence of phase of respiration on thoracic conformation at different vertebral levels. An observational prospective study was done on 30 German shepherd dogs. Thoracic radiographs were obtained at peak inspiration and expiration; thoracic depth and width were measured at each vertebral level. The change in thoracic dimensions, and the frontosagittal and vertebral indices were calculated at each level. The level of the 10th thoracic segment was the deepest and widest level of the thorax. At the first three thoracic segments, the percentage change of thoracic depth ranged from 3.2 ± 3.0 to 5.1 ± 3.9 % and 4.2 ± 2.8 to 6.6 ± 4.9 % for thoracic width. At the 4th-9th thoracic segments, this change increased to 13.3 ± 5.0 to 19.3 ± 3.8 % in thoracic depth and 13.9 ± 6.2 to 18.8 ± 8.2 % in thoracic width. The percentage change in thoracic width was significantly greater than thoracic depth at the level of the 6th and 7th thoracic segments (P = 0.027, 0.019). Phase of respiration had an influence on thoracic conformation objectively evaluated at multiple vertebral levels.
Keywords: Conformation; Dog; Radiograph; Respiration; Thorax.