Pleural effusions are fluid that collects at the costophrenic angle and causes blunting of the normally sharp costophrenic angle.

胸腔积液是积聚在肋膈角的液体，可使平时尖锐的肋膈角变钝。

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。