有过宫颈松弛的产妇问到：怎么看B超下宫颈的长度呢?

　　Have had the puerpera of cervix slack to ask: how to see the length of cervix below B ultra?

　　陈凤林教授指出：正常情况下宫颈管正常长度为2.5-3cm,当做妇科检查时，宫颈内口能顺利通过7号扩宫棒，或妊娠期无明显腹痛而B超测内口宽度>0.5cm,宫颈管长度<2.5cm,有助于宫颈松弛的诊断。

　　Professor Chen Fenglin pointed out that: under normal circumstances, the normal length of cervical canal is 2.5-3cm. When it is used for gynecological examination, the inner mouth of the cervix can pass the No.7 uterine expanding stick smoothly, or there is no obvious abdominal pain during pregnancy, while the width of the inner mouth measured by B-ultrasound is more than 0.5cm, and the length of the cervical canal is less than 2.5cm, which is helpful for the diagnosis of cervical relaxation.