The structurally anatomically narrow pelvis is not always also functionally, clinically narrow, that is, the size of the given birth object is not appropriate in size. In some cases, the pelvis will be “narrow” for a large fetus with a large, dense head, but normal for a fetus with a small, well-configured head. In other cases, the pelvis is dug enough in size in a primiparous woman and inadequate in the third or fourth birth in the same woman, since the size of the fetus and its head are usually larger during repeated births. That is why in clinical obstetrics the term “narrow pelvis” should not be used, but it is necessary to talk about anatomically, structurally narrow or, otherwise, narrowed pelvis and functionally, clinically narrow pelvis. The forms of the narrow pelvis are diverse and numerous. Npiboleo complete classification of the narrow pelvis comes L. Ya. Krassovsky. I. Uniformly narrowed pelvis: a) uniformly narrowed pelvis; b) pelvis of dwarfs; c) a children’s basin. II. Unevenly narrowed gas. 1. Flat basin: a) simple; b) rickety; c) luxurious (with bilateral hip dislocation); d) general judge. 2. Oblique pelvis: a) ankylotic ; b) coxalgic ; c) scoliosis ; d) kyphoscoliosis ; e) a pelvis with a unilateral dislocation of the thigh. 3. Cross- narrowed pelvis: a) ankylotic ; b) kyphotic ; c) spondylolistic ; g) funnel-shaped. 4. A collapsed pelvis: a) osteomalytic; b) rickety. 5. Split, or open in front of the pelvis. 6. The spinous basin. 7. A pelvis with a neoplasm. 8. The pelvis is closed. The given classification is currently of only theoretical interest, since many of the forms of the narrow pelvis listed in it are extremely rare in our country, and some are unfamiliar even to old experienced obstetricians.
This is explained by the fact that in our country a wide system of protecting children’s health, nutrition and living conditions, physical education, sports, favorable working conditions for mothers, the successful fight against childhood infections, rickets contributed to the almost complete disappearance of many of the reasons that acting on the girl’s body from the moment of her birth (or rather, even before birth), they created the prerequisites for the pathological development of the female pelvis. Currently, a narrow pelvis is found in 5.8-6.3% of all pregnant women (V. A. Pokrovsky, 1964). Among this small number of abnormalities of the female pelvis, the following few forms are more often observed and therefore mostly of practical importance: A. Generally constricted pelvis. B. Flat basin: 1) simple; 2) flat-planar. B. General narrow flat pelvis. According to world literature, most often there is a flat basin (50.8-62% of the total number of narrow basins); in the second place in frequency – the all-narrowed pelvis (38-49.2%). A pelvis is called narrow in which the external conjugate is equal to or less than 18 cm. It is more correct and more accurate to determine the degree of narrowing of the pelvis by the value of the true conjugate , the measurement of which is mandatory for all pregnant women without exception. It is necessary to distinguish 4 degrees of narrowing of the pelvis.
With the I degree of pelvic narrowing, in the vast majority of cases, childbirth ends spontaneously and their course differs little from that with a normal pelvis. In grade II, spontaneous birth is possible, but still not the rule. With grade III, the fetus cannot be born alive through the natural birth canal: it is removed only after craniotomy. IV degree of narrowing of the pelvis – an absolute indication for cesarean section, since the fetus, even reduced in size by surgery, cannot be removed through the natural birth canal. The frequency of individual degrees of narrowing of the pelvis, according to V. A. Pokrovsky, is: I – 78%, II – 21.2%, III – 0.8%; The author has never observed the narrowing of the fourth degree .