Ultrasonographic description of the caudal and ventral lung borders in normal Warmblood horses

The aim of the study was to describe the caudal and ventral lung border in clinically normal horses more precisely than it had been described previously and also to resolve the contradictions of data published in standard textbooks. Twenty‐two healthy Warmblood horses were used in the study. The lung border was determined by 2‐dimensional ultrasonography at the following anatomical levels: tuber olecrani, tuberositas deltoidea of the humerus, tuberculum majus of the humerus, tuber ischiadicum and ventral, mid‐ and dorsal points of the tuber coxae. Examinations were performed bilaterally at the end of inspiration and expiration. Distances between the actual lung borders and corresponding anatomical levels were measured and compared statistically. The results showed that the olecranon could not be used as an anatomical landmark. Instead, the deltoid tuberosity could be used as an alternative, as the lung border was found in the 7th intercostal space (ICS) in 14 horses and in the 8th ICS in 8 horses. The lung border at the level of the tuberculum majus was found in the 10th ICS in every horse. At the level of the tuber ischiadicum, the lung border was detected equally in the 14th (11 horses) and 15th (11 horses) ICS. At the level of the ventral and midpoint of the tuber coxae, the lung border was found in the 15th or 16th ICS. No lung border was found at the level of the dorsal point of the tuber coxae or in the 17th ICS.