The degree of descent is called the fetal station, which is described in terms of the relationship of the presenting part to mom's ischial spines.

下降的程度称为胎儿高度，以先露部分与母亲坐骨棘平面之间的关系描述。

The fetus moves from the pelvic inlet (which is about minus 5 station) down to the ischial spines (which is station 0), and this position's called engagement.

胎儿从骨盆入口（-5）向下到坐骨棘（0），这个位置称为衔接。