AP-PA

Anteroposterior or posteroanterior. This refers to (direnationality). An anteroposterior (AP) X-ray is one that sends X-rays from the front to the back of the body. A  posteroanterior (PA) chest X-ray is in opposite to this and involves X-rays that travel from the back to the front of the chest.

Anteroposterior AP前方位

Posteroanterior PA后方位

direnationality 方向性

AP- PA两个词是指人体方位的词语。AP(前方位)x-射线，是一种从身体前面发送到后面的射线。

PA(后方位) 胸部x-射线与此相反，涉及从胸部背面到前面的射线。