FORMS AND TYPES OF DEFORMED PELVES.
Although practically pelvic deformities may be divided into three classes, as viewed from an anatomical standpoint, there are several different varie ties. Schroeder describes among the common forms: 1. The generally and uniformly narrow pelvis.
2. The flattened pelvis, including the non-rachitic flattened, and the generally and irregularly contracted.
3. The flattened rachitic, including the simple flattened, the uniformly and generally contracted, the pseudo-osteomalacic, the acoliotic, the ky photic, and the kypho-scoliotic.
4. The pelvis flattened by reason of double dislocation of the hip.
5. The pelvis with congenital fissure of the symphysis.
Among the rare forms lie includes the following: The spondylolisthetic, kyphotic, funnel-shaped, obliquely-contracted, transversely contracted, osteomalacic, and the pelvis obstructed by foreign growths, etc.
Spiegelberg recognizes only three varieties, viz.: The simple flattened pelvis, rachitic or non-rachitic, the uniformly narrow, and the uniformly contracted and flattened.
Depaul distinguishes five prevailing conditions, rachitis, osteomalacia, abnormal development, deformities of other parts of the skeleton con nected with the pelvis, and fractures, dislocations, exostoses, etc.
Pinard also recognizes five principal types, as follows: 1. The rachitic pelvis, in which there is an exaggeration of the sacral curve, with descent of the promontory (pseudo-osteomalacic). 2. The rachitic pelvis, in which the promontory descends, while the sacrum is straight or even con cave. 3. The rachitic pelvis, in which the relative lengths of the diame ters is unchanged. 4. The pelvis in which the deformity is due to both rickets and some other pathological condition, as spinal disease. 5. The rachitic pelvis, in which there is extreme lateral deviation of the promon tory. He also describes other sub-varieties.
The Flattened Pelvis.
We have seen that the most common deformity consists in antero•os terior flattening, causing shortening of the conjugate diameters. Al
though this has until recently always been attributed to rachitis, Schroeder, Spiegelberg, and others, have observed it in women who presented no evidences of that disease. At first sight such a pelvis appears to be nor mal, but, on measuring it, we find that the antero-posterior diameter of the brim is shortened, so that the pelvis is flattened from before back wards. The other diameters are nearly normal, except the transverse, which is slightly increased, because of the outward curve of the ilia.
The contraction is accordingly confined to the superior strait and cavity, but, as the sacrum does not revolve on its transverse axis, its anterior clination is very slight, so that the contraction is usually slightly marked (never below 3.2 inches), and does not cause any serious difficulty during labor. In some cases, however, the sacrum is inclined forwards to a greater degree, so that there appears to be a second promontory, which may I* mistaken for the true one. The causes of this deformity are little known; they are due, perhaps, to carrying heavy burdens before puberty, as well as to retarded development.
As the women present no characteristic external appearance, the diag nosis of this condition can only be established by measuring the pelvis. The distances between the iliac crests and spines are but little changed, but the external conjugate is always shortened.
Schroeder has described a form of pelvis, to which he has given the name, "uniformly flattened and contracted pelvis." (Fig. 16.) It differs from the generally and regularly contracted type, only in the dispropor tion that exists between the conjugate and the other diameters. This sub-variety of the Germans seems to be more theoretical than practical, since flattened pelves are really rachitic pelves in which the rachitic ele ment is but slightly marked. When the rachitis becomes more marked, we have the flattened rachitic pelvis of German writers.