You can assess flatness on the lateral view by estimating that the hemidiaphragm is 1.5 centimeters above the line connecting the costophrenic angle posteriorly and sternophrenic angle anteriorly.

可以通过侧位片评估扁平度，正常情况下，膈肌比后方肋膈角与前方胸膈角连线高1.5厘米。