Once you have detected abnormal lung sounds you should try to assess their distribution and this can sometimes tell you what the most likely causes are. For example, the previous radiographs in the dog with aspiration pneumonia the abnormal lung sounds would be cranioventral and on the side where the disease was located. Other useful distributions are perihilar in some cases of left heart failure (a tough call to make but possible) and dorsocaudal in mild or moderate neurogenic oedema.When you have pleural space disease, the lung sounds are quiet or absent where the fluid, air or mass is and normal or harsher harsher in the areas where the lungs are. With pleural space disease the lungs are often partially collapsed and the airways are narrower hence more turbulence.