Diagnosis of a narrow pelvis

Diagnosis of a narrow pelvis is usually not difficult. Already a careful external examination of the pregnant woman is often a doctor vozpikaet thought of having a narrow pelvis: general physical hypoplasia, short stature ( mepype 150 cm), sharp lordosis, signs of childhood rickets (square skull, chicken breast, sablevidnoizognutye leg and so on.). Scoliosis, kyphosis, shortening of one of the legs, ankylosis, dislocations of the hip joints always signal the presence of certain pelvic deformities. The doctor receives very valuable data upon careful examination and measurement with a centimeter tape of the Michaelis rhombus . In well-built women with a normal pelvis, the rhombus has the shape of an almost regular square set on one of the corners (A. Yu. Lurie). With a uniformly narrowed pelvis, the transverse size of the rhombus is reduced by 1-1.5 cm, that is, it is 8-7.5 cm (instead of 9 cm); the longitudinal (vertical) size is slightly increased compared to the norm – 11 cm. The upper and lower corners of the rhombus approach acute, and the side corners approach obtuse. In other words, the rhombus is slightly flattened vertically. With a flat basin, on the contrary, the longitudinal size of the rhombus is reduced by 3-4 cm, while the transverse remains unchanged. Sometimes the upper half of the rhombus is so flattened horizontally that its upper corner disappears, and the rhombus turns into a triangle with a vertex facing down.

The asymmetrical shape of the rhombus usually indicates an oblique pelvis.
If you suspect a narrow pelvis, all its dimensions must be measured especially carefully and, moreover, repeatedly: during pregnancy and at the beginning of the first stage of labor. The fact that the pelvis during pregnancy peskolko increases obviously under the influence of hormonal influences: the true conjugate is extended to 0.5 cm In addition, during pregnancy is still impossible to judge the size of the fetal head at the time of delivery and its appropriate size. pelvis.

If a narrow pelvis is suspected, along with the usual measurement of the external dimensions, it is determined and compared with the following indicators.
1. The circumference of the pelvis. It is measured at the upper corner of the Michaelis rhombus , iliac scallops and the upper edge of the symphysis. Normally, the circumference of the pelvis is 85 cm. If its size approaches 75 cm, this indicates a significant narrowing of the pelvis. 2. Lateral conjugates (right and left). The measurement is made with a tazomer between the anterior and posterior iliac spine on each side; normal sizes of the lateral conjugates are 14.5-15 cm. Shortening them to 13 cm indicates a significant narrowing of the pelvis. 3. The oblique dimensions of the pelvis – the distance along the tazomer from the anteroposterior iliac spine of one side to the posterior- superior spine of the other. Each oblique size of a normal pelvis is 22.5 cm. A symmetrical decrease in these sizes is observed with a uniformly narrowed pelvis. The difference between the right and left oblique dimensions indicates the asymmetry of the pelvis. 4. The height of the pubic joint. It is determined by capturing with the thumb and forefinger the upper and lower edges of the pubic joint (A. Yu. Lurie). The distance between the toes was measured tazomera (in normo it is equal to 4-5 cm). The higher the pubic articulation, the smaller the true conjugate . At high lonnom articulation on the size of the true conjugates need to take 0.5 cm. Thus, if in normo true conjugate less diagonal average of 1.5 cm, the flat pelvis it is smaller by 2 cm. The diagonal conjugate is measured at the first intravaginal study of women in childbirth. Suspicion of a narrow pelvis is itself an indication for immediate vaginal examination with the obligatory measurement of diagonal conjugates . Simultaneously with the measurement, conjugates examine all the piles of the pelvis with your fingers to get an idea of ​​the structure, shape and capacity of the pelvis. 5. About the thickness of the bones of the woman in childbirth (and therefore about the thickness of the bones of the pelvis) gives an idea of ​​the Soloviev index – the value of the circumference of the wrist of the woman in labor , measured with a centimeter tape, write the styloid process. In norm, the Soloviev index is 14.5-15 cm. If the wrist thickness is less, then the bones of the woman, and therefore the pelvic bones are thin, and the capacity of the pelvic cavity, all other things being equal, will be greater. With a wrist thickness of 16 cm or more, the capacity of the pelvis with the same external dimensions will be less due to the thickness of the bones. 6. The angle of inclination of the pelvis , determined by a special tazomer , is also important : the larger the angle of inclination of the pelvis (on average it is 60 °), the greater the true conjugate , which with a narrow and especially with a flat basin is a favorable indicator. 7. The size of the fetal head can be judged approximately by the length of the fetus and the diameter of the head, measured with a tazomer across the entire thickness of the abdomen, which is very inaccurate, and in cases of an excessively thick, strained abdominal wall. Therefore, the following two methods for determining the relationship between the fetal head and the mother’s pelvis are of great practical importance. Sign of Vasten . The doctor, standing on the side of the woman in childbirth, puts a palm on her pubis, straightening her fingers, and then moves the brush with a sliding motion upward on the head. In this case: 1. The edge of the palm of the hand of the obstetrician, when moving upward, encounters, as it were, a hill protruding above the upper edge of the symphysis. This is the head of the fetus; it is pressed to the symphysis and is not inserted, since its dimensions do not correspond to the dimensions of the pelvis. Therefore, it will stand, as if hanging over the symphysis. This position is referred to as positive vasten . 2. The edge of the brush, when moving upward, as if jumps from the upper edge of the symphysis to the fetal head, since the head is freely inserted into the pelvic entrance and its surface is located below the surface of the symphysis; in such a case they say: ” negative vasten “, which indicates the absence of any mismatch between the size of the fetal head and the entrance to the mother’s pelvis. 3. The edge of the hand freely moves upward from the symphysis, to the fetal head, remaining in the same plane, since the surface of the symphysis and the fetal head, firmly pressed to the entrance to the pelvis (but not yet inserted), are also in the same plane. This polo { ix called ” Vastu level.” It indicates the presence at the moment of some slight mismatch between the pelvis and the head, which, as a rule, is overcome with the development of good labor and a pronounced configuration of the fetal head. There is reason to believe that the head will pass the entrance of the narrowed pelvis. The Vasten sign is one of the very important criteria for assessing pelvic functional failure. However, its character can only be judged with a fixed fetal head. For greater persuasiveness of the results obtained using the Vastep method, the Zapgemeister method is used . In a standing position, women in labor determine the external conjugate of the pelvis with a tazomer ; remembering the figure obtained and without shifting the buttons of the posterior jaw of the tazomere , the button of the front jaw is moved from the upper edge of the symphysis to the most prominent point of the underlying fetal head.

 If the resulting figure is less than the magnitude of the external conjugates , the prognosis is good; if more, the forecast is bad, if the numbers are the same, the forecast is uncertain: everything will depend on the nature of labor and the configuration of the head. We repeat: with a narrow pelvis during childbirth, repeated vaginal examination is necessary. In this case, the ratio of the fetal head with the entrance to the pelvis, asynclitism and its types, degree of head configuration, condition and location of the fontanelles, insertion of the head, presence and location of the birth tumor, features of the pelvis (determination of the true conjugates , degree of coccyx mobility, the presence of exostoses, the nature of the promontory are determined , capacities and forms of the sacral cavity ). Without knowledge of all these data, proper management of labor is impossible. At I and II degrees of narrowing of the pelvis, delivery through the natural birth canal is possible in most cases, but under the following conditions (according to A. Yu. Lurie): 1) the circumference of the pelvis is at least 75-80 cm; 2) lateral conjugates – not less than 14 cm; 3) Soloviev index – not more than 14 cm; 4) the direct and transverse dimensions of the outlet of the pelvis – not less than 10 cm; 5) bosom height – no more than 5 cm; 6) the angle of inclination of the pelvis approaches 60 °; 7) The direct resolution of the head (on paruzhnomu definition tazomera ) – no more than 10-11 cm; 8) ” vasten is negative” or “level”; 9) “ Tsangmeister is positive” in favor of external conjugates . To this it is necessary to add carefully analyzed data on the size of the fetus, the degree of configuration and the nature of the insertion of the head; strength, duration, regularity and productivity of labor pains; amniotic fluid; the state of the fetus (often listening to his heartbeat or, better, with the help of phonoelectrocardiography ); the general condition of the woman in labor, the degree of her fatigue.

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