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 a pelvic outlet measuring device, the examiner faces the vulva of the pregnant woman during the measurement, and mainly measures and records the following items: 1. inter-iliac spine diameter: measuring the distance between the lateral edges of the anterior superior iliac spine on both sides; 2. inter-iliac crest diameter: measuring the widest distance between the lateral edges of the iliac crest on both sides, which can indirectly understand the length of the transverse diameter of the pelvic entrance; 3. sacro-pubic outer diameter: measuring the distance from the midpoint of the superior border of the pubic symphysis to the depression under the spinous process of the fifth lumbar vertebra; 4. 4.Exit transverse diameter: measure the distance between the inner edges of the two sciatic tuberosities; 5.Exit posterior sagittal diameter: the distance between the sacrococcygeal joint and the midpoint of the sciatic tuberosity diameter, that is, the posterior sagittal diameter of the exit; 6.Pubic arch angle: use the left and right thumb tips obliquely together, placed on the lower edge of the pubic symphysis, the left and right thumbs flat on top of the pubic descending branch, measure the angle between the two thumbs and record. 2. Intrapelvic 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 capsule, 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, which is the diagonal diameter; 2. 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.