McDonell W N, Hall L W, Jeffcott L B
Equine Vet J. 1979 Jan;11(1):24-32. doi: 10.1111/j.2042-3306.1979.tb01290.x.
Studies in conscious and anaesthetised ponies demonstrated that starvation, anaesthesia and changes in body position influence the radiographic appearance of the lungs in the lateral and dorsoventral views. Radiographic appearances could not be closely correlated with blood gas values, but they suggested that the volume of the lowermost lung of the laterally recumbent animal is greatly reduced.