Before delivery, a pelvic measurement is performed to assess whether the fetus can be delivered vaginally. The pelvic measurements are divided into external and internal pelvic measurements. 1.External pelvic measurement: Using the pelvic outlet measuring device, the examiner faces the vulva of the pregnant woman when measuring. 4.Exit transverse diameter: measure the distance between the inner edges of the two sciatic tuberosities; 5.Post-exit sagittal diameter: the distance between the midpoint of the path between the sacrococcygeal joint and the sciatic tuberosity is the post-exit sagittal diameter; 6.Pubic arch angle: use the tips of the left and right thumbs together obliquely and place them on the lower edge of the pubic symphysis, the left and right thumbs are placed flat on top of the descending pubic bone, measure the angle between the two thumbs and record. 2.Intra-pelvic measurement: use the middle pelvic measuring device, mainly measure the following items: 1.Diagonal diameter: the examiner reaches into the vagina, the tip of the middle finger touches the midpoint of the upper edge of the sacral cape, the upper edge of the index finger is placed close to the lower edge of the pubic symphysis, mark this contact point correctly with the index finger of the other hand, withdraw the finger inside the vagina, measure the distance between the tip of the middle finger and this contact point, that is, the diagonal diameter; 2.Sciatic interspinous diameter: the measurement method is to put the index finger and middle finger of one hand into the vagina, touch the two sides of the pubic symphysis respectively. The width of the sciatic notch: the width is the distance between the sciatic spine and the lower part of the sacrum, that is, the width of the sacral spinal ligament.