横位是指胎儿横卧在子宫腔内,胎体纵轴和母体纵轴相交叉,胎儿肩胛部处于最低处,所以产科学上称为肩先露。在叙述这个题目之前,先打一个简单的比喻:若从一个狭窄的门口搬出一张长桌来,自然要顺着它的长轴往外搬,才能顺利通过。假如横着往外搬就搬不出去,再用蛮力往外搬,势必毁了桌子,甚至损坏了门和墙。在产科工作中,对妊娠足月或接近足月的横产式,如不 Horizontal refers to the fetus lying in the uterine cavity, the longitudinal axis of the carcass and the longitudinal axis of the mother cross, fetal scapular at the lowest point, so obstetric called shoulders first dew. Before describing the subject, first make a simple metaphor: if a long table is to be moved out of a narrow door, it is natural to move along its long axis to pass smoothly. If you move sideways out and move out, then brute force to move out, it is bound to ruin the table, and even damaged the door and the wall. In obstetrical work, the full-term pregnancy or near full-term type of production, if not