Radiological measurements from the feet of normal horses with relevance tolaminitis

Lateromedial radiographic projections were made from the feet of 25 normal horses and 3 angles and 3 distances were measured. From these, normal range s of calculated variables were obtained. The width and length of each foot and the height of the horse at the withers was also measured. In view of it s possible importance in clinical laminitis, particular attention was paid to 'founder' distance (D), This is the vertical distance between the proxim al limit of the dorsal hoof wall and the proximal limit of the extensor pro cess of the distal phalanx. There were significant differences between bree ds in D (P<0.05) and in wall thickness (P<0.01). Further studies investigat ed the effects of time, differing radiographic projections and different op erators on D. D did not alter significantly (P>0.05) over a 6 week study pe riod. It was concluded that errors due to radiographic beam obliquity were not of practical importance. Errors in measuring D between operators can be minimised by use of a standard radiographic technique. Although there was some variation in the value of D measured over time and with different oper ators, which could make the interpretation of early or subtle changes diffi cult, measurement variation was not considered to interfere with the assess ment of large changes associated with severe laminitis.