Both are small and narrow

Introduction When the pelvic inlet, the middle pelvis and the exit plane are both narrow, they are said to be small and narrow. Can be divided into 3 types: 1 The shape of the pelvis still maintains the shape of the female pelvis, and only the diameter of each plane is less than the normal value of 1 to 3 cm. Small pelvis is more common in women with poor stature. 2 simple flat pelvis, but the anteroposterior diameter of the three planes are shortened. There are 3 types of human pelvis type pelvis, and the transverse diameters of the three planes are small. It is a symptom of abnormal dystocia in the bone birth canal.

Cause

The shape of the pelvis is normal, but each radial line can be shortened by more than 2 cm from the normal value. Therefore, its various planes are reduced to some extent. More common in short women.

an examination

Related inspection

Pelvic measurement CT examination

1. If the medical history has the following medical history, such as vitamin D deficiency, osteomalosis, poliomyelitis, spinal and hip tuberculosis, severe thoracic or spinal deformity, pelvic fracture, and cesarean section, vaginal surgery midwifery, Repeated breech or transverse position of maternal, stillbirth, neonatal birth injury, etc., should be carefully examined for pelvic abnormalities.

2. Physical examination

(1) General examination: a short stature, less than 145cm of the mother, the possibility of small stenosis of the pelvis is greater. The body is thick, the neck is short, and the bones are masculine. It is not only affected by the thicker bone, but also the funnel-type stenosis. The lower limbs are unequal in length, which can lead to pelvic deformities. Therefore, it is necessary to carefully check whether there are any lower limb or spinal diseases that affect the pelvic morphology, whether there is vitamin D deficiency or sequelae of pelvic fractures.

(2) Pelvic measurement:

1 Measurement outside the pelvis: A. The outer diameter of the shame is <18cm, which indicates that the posterior diameter of the entrance is narrow, often a flat pelvis. B. The diameter of the ischial tuberosity <7.5cm, the outlet diameter should be considered narrow, often accompanied by pelvic stenosis. C. The ischial nodular diameter + posterior sagittal diameter <15cm or the pubic arch angle is acute and the pubic arch is low, also suggesting that the outlet is narrow. D. Mie's diamond shape is asymmetrical, and the sides are not equal, which may be a skewed pelvis. E. Measurement of each diameter outside the pelvis is 2 cm or more smaller than the normal value, suggesting a small pelvic stenosis.

2 pelvic measurement: If pelvic stenosis is suspected when measuring outside the pelvis, intrapelvic measurements should be taken in late pregnancy or after delivery. The internal measurement shall be carried out after disinfection of the vulva and vagina after wearing the middle finger of the disinfecting glove and indicating the transvaginal examination.

Differential diagnosis

A. Diagonal diameter: It is the distance from the lower edge of the pubic symphysis to the iliac crest. The normal value is 12.5~13cm. The diagonal diameter minus 1.5cm is equal to the back diameter of the pelvic entrance, which is the true combined diameter.

B. Ischial spine diameter: also known as the middle pelvis transverse diameter, this diameter is not easy to measure, the following methods can be used:

a. De-Lee pelvic measuring device, but the end of the device is difficult to fix, so it is not easy to check accurately; b. It is suggested that the finger touches one side of the ischial spine and then swept to the other side during internal diagnosis. The hand index estimates its length, but it is not accurate enough. Clinical estimates can be taken when it is not possible to know exactly the diameter of the ischial spine:

a. It can be considered that the diameter of the posterior superior iliac spine, that is, the diameter of the Mie diamond, plus 1 cm as the diameter of the ischial spine.

b. An easier way is to divide the degree of tibial spine into 3 levels to indicate the length of the ischial spine.

Grade I: The ischial spine is relatively flat, and the diameter of the ischial spine is longer; Grade II: the ischial spine is moderately prominent, and the ischial spine diameter is also medium length; Grade III: the ischial spine sharply protrudes, and the ischial spine diameter is short. c. Refer to the length of the ischial nodule diameter.

C. The anterior and posterior diameter of the pelvis: first determine the appendix joint, then use the internal fingertips to follow the joint upwards, and save the 1cm over the humerus. Here, the junction of the 4th and 5th atlas is the post-measure of the measurement. The site is still the lower edge of the pubic symphysis. The average anteroposterior diameter of the middle pelvis was 12.2 cm.

D. Middle pelvic sagittal diameter: This diameter can not be directly measured, but it can be represented by the width of the bottom of the sciatic notch. It can accommodate 3 horizontal fingers as normal. If 2 horizontal fingers indicate that the sagittal diameter of the middle pelvis is obviously shortened. The width of the notch is more accurate with the anal examination, and the vaginal examination is not easy to reach, especially the primipara.

E. Shame joint back angle: This angle should be >156o. If you feel that the back angle of the shame joint is wider, it means the female pelvis. If it is smaller, it is the sputum type or the male pelvis.

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