【单句求助】in the zone of apposition

During the trial, the right hemi-diaphragm was visualized in the zone of apposition using a 10-MHz linear ultrasound probe.
看到好几篇文章里头都有提到超声看右侧膈肌的in the zone of apposition，但是不知道这个in the zone of apposition到底应该怎么翻译，指的是右膈的什么位置，请大家帮忙，谢谢！