breech

后膛

He opened the breech and slid a fresh cartridge into place.

他打开后膛，把一颗新的弹药推进去。

臀位医学

The doctor confirmed that the baby was in breech.

医生确认胎儿是臀位。

臀位的医学

A breech delivery often calls for extra monitoring during labor.

臀位分娩在产程中通常需要更密切的监测。