A young male for medical check up shows accentuated difference in heights of the domes of approximately 35mm with rest of the study normal including supra and infra diaphragmatic regions which may suggest unusual causes like eventeration.
Teaching points by Dr MGK Murthy
1. Usual accepted range in vertical deep inspiratory position of CXR is 5 to 25mm between cupolae (Right higher than left in about 95% of normal individuals)(X ray beam centered at D4) (unless lot of swallowed air in stomach or colonic distension changes this equation)
2. Level is counted in terms of ribs in relation to the highest point in mid lung field as the dome is clearly discernible at this levels and anterior ribs are closer to the film than posterior ones .
3. Least chance of shadow of anterior ribs or diaphragm being projected downwards if centering beam is unusually high or leaning forward of the patient (common error)
4. Disadvantage is anterior ribs move cranial more than posterior ones in inspiration, down ward slope of anterior ribs is variable & length differs in individuals
5. In about 95% individuals , right dome between 5 to halfway between 6&7 (anterior). Stocky or fat could be as high as 4th and asthenic lean persons as low as 7th
6. 15% of normal children between 5-15 years will have right dome below halfway between 6&7 ribs because ribs are shorter and more horizontal than adults.
7. Domes levels with respect to dorsal vertebrae include Right (D11/D12)and left (D12) on inspiration , D8 (right) D9 (left) on expiration
8. Though anatomically Supine position makes dome 3 cm higher than vertical position & if he rolls on one side /prone position, dome higher that side (because of pressure of viscera), In practice these are hardly conspicuous on radiographs and are usually not significant
9. Patholgical causes of course include paresis, eventeration and intra abdominal volume increase (gas, fluid, SOL etc ), reduced lung compliance (SLE) and lung collapse etc
Elevated Dome of Diaphragm -CXR Teaching Points
4/ 5Oleh Habifa