Flat pelvis

Introduction The flat pelvis is a long oval shape at the entrance of the pelvis. The transverse diameter of the entrance is larger than the anteroposterior diameter. The lateral wall of the pelvis is straight, the pubis is wide, the humerus loses its normal curvature, and the sacral bone is straight or backward. More common, women in China account for about 23.2%-29%. The anterior and posterior diameter of the pelvic entrance is shortened, and the transverse diameter is normal. Most of them are the result of rickets in childhood. The characteristics of this type of pelvis are: the sloping forward, protruding into the pelvic inlet, shortening the anterior diameter of the entrance plane, and moving the lower part of the humerus backward.

Cause

There are two causes:

1 simple flat pelvis, caused by congenital growth factors.

2 rickets flat pelvis due to childhood rickets, bone softening, deforming the pelvis.

an examination

Related inspection

Estimation method for pelvic measurement head basin

(1) medical history

You should be asked if you have had rickets, polio, tuberculosis, etc. during childhood, as well as past childbirth.

(2) General inspection

Pay attention to the general development. Short stature, abnormal fetal position, primipara before the birth of the fetus, and/or a drooping abdomen may indicate that the pelvis may be narrow. For walkers, the pelvis may tilt.

(three) pelvic measurement

The flattened pelvis of the outer diameter of the shame; the smaller than the normal value of 1.5cm or more is the small pelvis; the diameter of the ischial nodular joint is less than 7cm, and there is a middle stenosis at the same time, and should be further measured in the pelvis:

1. Measure the "diagonal diameter": the food and the middle finger are inserted into the vagina, and the distance between the lower edge of the sacral and pubic symphysis is measured. The tibia curvature, the protrusion of the ischial spine and the width of the pubic bone should be understood at the same time. Straight or ischial spine into the pelvic cavity is more significant, indicating the possibility of pelvic stenosis.

2. X-ray pelvic measurement: one piece of anterior and posterior pelvic pelvis, which can more accurately measure the plane diameter of the pelvis, and can observe the shape of the pelvis, the orientation of the tire and the relationship between the head and the basin. This method is rarely used at present.

(four) head basin relationship check (trans-shame)

The mother is lying down and checking the relationship between the fetal head and the pubic symphysis. The head is lower than the level of pubic symphysis, said the trans-symptom sign (1), indicating that the headless basin is not called; both are at the same level, suspicious for the trans-symptom, may have a mild head basin; the head is higher than the pubic symphysis level For those who are positive for trans-symptoms, it means that there is a clear head basin.

Differential diagnosis

Identification: Different from fractured pelvic malformation, fractured pelvic deformity is generally caused by a clear traumatic factor, which can be judged after examination.

1 simple flat pelvis: the squat protrudes forward and downward, so that the anterior and posterior diameter of the pelvic inlet is shortened and the transverse diameter is normal;

2 rickets flat pelvis: due to childhood rickets, bone softening, deformation of the pelvis, sputum is pressed forward and the appendix bone protrudes forward in the exit plane, ischial tuberosity valgus, so except for the entrance anteroposterior diameter shortened, the exit horizontal The path is widened. A preliminary diagnosis can be made by pelvic measurements. At the end of pregnancy or after labor, the sagittal suture of the fetal head can only be connected to the entrance.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.