Flattening of the diaphragm
Flattening of the diaphragm is the most sensitive sign on chest radiographs for the presence of hyperinflation of the lungs, usually due to emphysema 1-2.
The normal dome of each hemidiaphragm should rise at least 1.5cm above a line connecting the costophrenic angle posteriorly and sternophrenic angle anteriorly 1.
- 1. Chest radiology. edited by Jannette Collins, Eric J. Stern. Philadelphia : Wolters Kluwer Health/Lippincott Williams & Wilkins, c2008. ISBN:0781763142 (find it at amazon.com)
- 2. Robertson RJ. Imaging in the evaluation of emphysema. Thorax. 1999;54 (5): 379. doi:10.1136/thx.54.5.379 [free text at pubmed] [pubmed citation]