Funnel pelvis

Introduction The diameter of the pelvic inlet plane is normal, but the middle pelvis and the exit plane are both narrow. The sides of the pelvis are inclined inward like a funnel, so it is called a funnel-shaped pelvis. The diameter of the ischial spine is <10cm, the diameter of the ischial tuberosity is <8cm, the sum of the ischial nodule diameter and the posterior sagittal diameter is <15cm, the pubic arch angle is <90°, and the width of the ischial incision is narrowed. In general, the female pelvis is broad and short, the pelvic wall is smooth, thin, and the bone is light. The upper pelvis is round or elliptical. The front and back are wide. The pelvis is wide and shallow, and it is round and the pelvis is wide. The pubic symphysis is wide and short, flexible, and the pubic arch angle is large, 90 to 100°, the closed hole is approximately triangular, and the acetabulum is small. The funnel pelvis is a clinical manifestation of a narrow pelvis.

Cause

The pelvic diameter line is too short or abnormal in morphology, resulting in the pelvic cavity being smaller than the limit of the first exposed part of the fetus, which hinders the decline of the first exposed part of the fetus and affects the smooth progress of the labor process, which is called the narrow pelvis. A narrow pelvis can be too short or multiple short lines, or a narrow plane or multiple planes. When a radial line is narrow, it is necessary to observe the size of other radial lines in the same plane, and then comprehensively analyze the size and shape of the entire pelvis to make a correct judgment. Caused by rickets, polio, spinal and hip tuberculosis, and traumatic history.

an examination

Related inspection

Pelvic extrusion test pelvic measurement pelvic measurement extrapelvic measurement

The pelvis is a constant factor during childbirth. The narrow pelvis affects the decline and internal rotation of the fetal position and the exposed part of the fetus in the delivery mechanism, and also affects contractions. The pelvis is an important factor to consider when estimating the difficulty of childbirth. During pregnancy, you should check whether the pelvis is abnormal, whether the head basin is not called, and make a diagnosis early to determine the appropriate mode of delivery.

1. History: Ask the pregnant woman about rickets, polio, polio, spinal and hip tuberculosis, and traumatic history. If you are a mother, you should know whether there is a history of dystocia and its causes, whether the newborn has a birth injury or not.

2. General examination: measure the height, if the height of the pregnant woman is below 145cm, should be alert to the small pelvis. Pay attention to the body shape of the pregnant woman, whether there is squatting in the gait, whether there is a spine or hip deformity, whether the Mie's diamond-shaped nest is symmetrical, whether there is a sharp abdomen or a drooping abdomen.

3. Abdominal examination

(1) Abdominal morphology: pay attention to the abdominal type, measure the length of the upper uterus and the abdominal circumference, and observe the relationship between the first exposure of the fetus and the pelvis by B-mode ultrasound, and also measure the double top diameter, breast diameter, abdominal diameter and femur length of the fetal head. Predict fetal weight and determine whether it can pass through the bone birth canal.

(2) abnormal fetal position: pelvic inlet stenosis often because the head basin is not called, the fetal head is not easy to enter the basin, resulting in abnormal fetal position, such as the first gluteal, the first exposed. The middle pelvic stenosis affects the rotation of the fetal head that has entered the basin, resulting in continuous occipital transverse position and posterior occipital position.

(3) Estimation of head and basin relationship: Under normal circumstances, some pregnant women should be in the basin 2 weeks before the expected date of delivery. If the birth is still in place and the fetal head is still not in the basin, the head basin relationship should be fully estimated. Check the specific method of whether the head basin is commensurate: pregnant women empty the bladder, supine, legs straight. The examiner places his hand over the pubic symphysis and pushes the floating fetal head toward the pelvic cavity. If the fetal head is lower than the plane of the pubic symphysis, it means that the fetal head can enter the basin. The head basin is symmetrical, which is called the trans-shadow sign. If the fetal head and the pubic symphysis are in the same plane, it means that the suspicious head basin is not called. Positive; if the fetal head is higher than the pubic symphysis plane, it means that the head basin is obviously not called, which is called positive across the shame. For pregnant women with positive cross-symptoms, they should take the two-leg flexion semi-recumbent position and re-examine the fetal head cross-symptom sign. If it turns negative, it indicates that the pelvic inclination is abnormal, not the head basin.

4. Pelvic measurement

(1) Measurement outside the pelvis: Measurement of each radial line outside the pelvis <normal value 2cm or more for the small pelvis; flat outer diameter <18cm for the flat pelvis. The ischial tuberosity is <8cm, and the pubic arch angle is <90°. It is a funnel-shaped pelvis. The slanting diameter on both sides of the pelvis (the distance from the anterior superior iliac spine to the contralateral superior iliac spine) and the ipsilateral diameter (distance from the anterior superior iliac spine to the ipsilateral superior iliac spine), the difference between the two 1cm is a skewed pelvis.

(2) Measurement in the pelvis: Abnormalities in the lateral pelvis are found, and intrapelvic measurements should be performed. The diagonal diameter is <11.5cm, and the sacral protrusion is a flat pelvic entrance plane, which belongs to the flat pelvis. The pelvic plane stenosis and stenosis of the pelvic outlet plane often coexist. The anterior curvature of the humerus, the diameter of the ischial spine, and the width of the ischial incision (ie, the width of the sacrospinous ligament) should be measured. If the diameter of the ischial spine is <10cm, the width of the ischial incision is <2, which is the plane of the middle pelvis. If the diameter of the ischial tuberosity is <8 cm, the sagittal diameter after the exit should be measured and the mobility of the appendix joint should be examined to estimate the degree of stenosis of the pelvic outlet plane. If the sum of the ischial tuberosity and the posterior sagittal diameter is <15 cm, the pelvic outlet plane is narrow.

Differential diagnosis

Differential diagnosis of the funnel pelvis:

1. Transversely contracted pelvis: similar to a humanoid pelvis. The transverse diameters of the pelvic inlet, the middle pelvis and the pelvic outlet are shortened, the anterior and posterior diameters are slightly longer, and the ischial incision is wide. The external diameter of the shame was measured to be normal, but the intercondylar diameter and the intercondylar diameter were shortened.

2, simple flat pelvis (simple flat pelvis): the entrance of the pelvis is flat and round, the squat protrudes forward and downward, so that the anterior and posterior diameter of the pelvic entrance is shortened and the transverse diameter is normal.

3, rickets flat pelvis: due to childhood rickets, bone softening, pelvic deformation, sputum is pressed forward, pelvic entrance anteroposterior diameter is significantly shortened, so that the pelvic entrance is kidney-shaped, the lower part of the humerus moves backward, losing the normal curvature of the humerus, Straighten straight back. The tailbone is hooked to the pelvic outlet plane. Due to the abduction of the humerus, the diameter of the iliac spine is equal to or greater than the intercondylar diameter; due to the valgus of the ischial tuberosity, the angle of the pubic arch is increased and the transverse diameter of the pelvic outlet is widened.

The pelvis is a constant factor during childbirth. The narrow pelvis affects the decline and internal rotation of the fetal position and the exposed part of the fetus in the delivery mechanism, and also affects contractions. The pelvis is an important factor to consider when estimating the difficulty of childbirth. During pregnancy, you should check whether the pelvis is abnormal, whether the head basin is not called, and make a diagnosis early to determine the appropriate mode of delivery.

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