The pelvis is a part of the female reproductive system, and its size determines whether a woman can give birth naturally. Generally, those with a smaller pelvis may experience difficult labor. Many women need to measure the size of their pelvis before giving birth to determine which delivery method to use. This article discusses pelvic measurements and the normal values for pelvic measurements.
Definition of pelvic measurement
Pelvic measurement refers to the use of pelvic measuring instruments to measure the pelvic area of pregnant women, which is an essential item for prenatal examinations. The pelvis can support and protect the reproductive organs and other organs inside the pelvis, and it is also the most important component of the birth canal. It is an important passage for the fetus to be born during childbirth, and its shape and size are related to whether it can be delivered smoothly. Therefore, pregnant women must undergo pelvic measurement and examination during the first prenatal examination. Pelvic measurement is divided into external pelvic measurement and internal pelvic measurement. In order to determine the size and shape of the pelvis and understand the ratio between the fetus and the pelvis, the pelvis should be measured during prenatal examination.
Pelvic measurement data
The size of the pelvis is represented by the distance between the bones, which is the size of the pelvic diameter line. The size and shape of each person's pelvis are influenced by their physical development, nutritional status, genetics, and ethnic differences. Therefore, within the normal range, the length of each pelvic diameter also varies to some extent. The pelvic diameter values currently described in various sources are the average values of many normal pelvic bones.
1. The pelvic shape is normal, but each diameter line is more than 2 centimeters below the minimum value of the normal diameter line. The diagnosis is a small pelvis and difficult labor may occur.
2. If the pelvic shape is slightly abnormal, but all diameter lines are greater than the normal low value diameter line, vaginal delivery may be successful.
3. When the sacral outer diameter (EC) is less than 18cm and the diagonal diameter (DC) is less than 11.5cm, the diagnosis is a flat pelvis.
4. When the angle of the pubic arch is less than 90 °, the diameter between the ischial nodules is less than 8cm, the sum of the diameter between the ischial nodules and the sagittal diameter of the exit is less than 15cm, and the width of the bone incision is less than 2 transverse fingers, the diagnosis is funnel-shaped pelvis.
5. The width of the ischial notch indirectly reflects the size of the posterior sagittal diameter of the middle pelvis. Middle pelvic stenosis is often accompanied by pelvic outlet stenosis. By measuring the diameter between the ischial nodules, the degree of the ischial spinous process, and the width of the ischial notch, the degree of middle pelvic stenosis can be indirectly determined.
Pelvic measurement normal value
In clinical practice, pelvic external measurements are usually performed first, with a normal value of 23-26 centimeters for the anterior superior iliac spine diameter, 25-28 centimeters for the iliac crest diameter, a sacral and pubic outer diameter greater than 18.5 centimeters, 28-31 centimeters for the greater trochanter diameter, 8.5-10 centimeters for the ischial tuberosity diameter, and a pubic arch angle greater than or equal to 90 degrees.
If there are abnormalities in the measurement of various diameter lines or a certain diameter line outside the pelvis, pelvic measurements should be taken during labor, and a normal delivery method should be selected based on fetal size, fetal position, and labor force. If there are abnormalities in the measurement of various diameter lines or a certain diameter line outside the pelvis, pelvic measurements should be taken during labor, and a normal delivery method should be selected based on fetal size, fetal position, and labor force.
Pelvic measurement is now quite common and an important indicator for determining whether vaginal delivery is possible. It is best for pregnant women to have it measured before delivery to avoid panic caused by busy hands and feet during delivery.
