Briefly describe the clinical types, diagnostic criteria and related clinical significance of pelvic stenosis.

The types of pelvic stenosis are as follows.

(1) Pelvic inlet stenosis: sacrum outer diameter < < 18cm, diagonal diameter (from pubic symphysis down to the sacral promontory)? 1 1.5cm, be alert to flat pelvis, and measure the entrance and anteroposterior diameter by X-ray or ultrasound.

(2) Middle pelvic stenosis: During vaginal examination, the double ischial spines are obviously prominent and the pelvic side wall is adhered. The diameter between ischial spines measured by X-ray is less than < 10cm.

(3) Pelvic outlet stenosis: transverse diameter of pelvic outlet

(4) Even small pelvis: The pelvis measured by clinic or X-ray, whose diameter is less than 2cm above the normal low value, can be diagnosed as even small pelvis.