In Naegele's collection is the pelvis of a female dwarf, aged thirty-one years, whose height was 3 feet 6 inches, the measurements of which are given as a specimen of a distinct kind of "pelvis equabditerjusto minor" by that eminent author in the Appendix to his valu able work—" Das schriig verengte Beelten," as follow — la. line! Between the sacral promont. and tip of coccyx - - 3 3 Between the sciatic tuberosity and iliac crest - 5 5 Between sciatic tuberosity and linea innorn. - - 2 7 Superior opening, conjugate diam. - 3 0 transverse do. - 3 7 Cavity antero-postr. do. - 3 31 transverse do. - 3 0 Inferior opening, transverse diarn. - 3 0 Length of pubic syniphysis - - 0 I The pelvis was perfectly regular and nor mal in symmetry and proportion, presenting all the appearances, in these respects, of the adult "standard." The sub-pubic arch, the sacral curves, the direction of the ischia and the curvature of the pectineal line were per fectly regular. The sacral bones, however, and the three pieces of the innominate bones, were united by cartilag,e only, ossification not having taken place. In this respect only is this pelvis allied to the class of deformities re sulting from imperrect development. or to an im mature pelvis. These peculimities may possibly be explained by supposing the " arrest of de velopment," which dwarfed the woman, to have taken place after the age of puberty, and the development of the sexual organs, but before the union of the sacral arid innominate pieces, that is, between the fourteenth vnd sixteenth years. This supposition is moreover strength ened by the fact, that the ischio-pubic rami were firmly united, that the woman bad men struated at the proper period. and that all the limbs were in normal proportion to the body: Neither in the history of the case, nor in the appearance of the skeleton, was there any sign of rickets. The woman had become pregnant, and by the advice of the medical attendants, prernature labour was in duced at the sixth month, and the patient was safely delivered by the forceps, but died ten days afterwards from the consequences of in discretion in diet.
Out of the three cases of pelvis equabiliter justo minor given by Professor Busch *, and quoted by Dr. Rigby, there was a fatal termi nation in two instances. In one case, the pelvic diameters were universally half an inch below the standard size. In another, nhich resembled that of a child, they were contracted in every direction three quarters of an inch. The last ought, probably, to come under the denomination of an infantile pelvis.
In the above cases, the contraction of the pelvic diameters is marked and absolute ; but there is a considerable class of cases, included among the variations of measurement of normal pelves, in which the diameters are diminished in a much less degree, and yet their relative disproportion to those of a bulky fcetal head may be so great as to call for instrumental aid in parturition. Naegele, however, concludes that the contraction of the pelvis itself (without any complication with unusual bulk of fcetus) should be con sidered, in most cases, as the cause of the difficulty- of labour, and that this kind of faulty pelvis merits the especial attention of the accoucheur as much as others, and the more, that from the absence of evident ex ternal syinptoms, the difficulty of diagnosis is greater than in rickets or malacosteon.
The cause of most of the cases of propor tionably contracted and enlarged pelves is only to be looked for among those of Nature's aberrations which result in heads, extremi ties, &c. disproportionate to the rest of the body. The small pelvis may be considered as one in vvhich the development in shape has gone on to completion, but the development in size arrested by some cause. This cause
has been attributed by Mr. Shaw to a general rickety disease in many cases.
In addition to its effect in seriously im peding the passage of the fcetal head, a small pelvis of this kind is said by Ranisbotham to cause retroversion of the uterus in some cases.
Irregularities from impelled development. Infantile pelvis —This form of pelvis is cha racterised by the persistence of the form of the pelvis which is normally but transitorily pre sent under the age of puberty. Its appear ance corresponds, in some degree, with the characters of the infantile pelvis described in the first section of this article, of which, in the respect under consideration, the most im portant are, the preponderance of the antero posterior diameters, which are larger than the transverse ; the contraction of the sub-pubic arch ; the shallow and diminished cavity ; the approximation of the ischial tuberosities ; the flat, expanded, shallow, and rounded ilia, and the increased obliquity of the superior plane. The pieces of the sacrum and innominate bones are generally incompletely united by ossification.
In a pelvis described by Naegele t, taken from an idiot girl aged twenty-one )ears, yam was only 4 feet high, and had never walked nor menstruated, the sacrum and innominate bones were connected by cartilage only, but the ischio-pubic rami were united. It pre sented, in size as well as form, the charac teristics of that of a child of six or seven years old. The conjugate diameter was larger than the transverse, the ilio-pectineal line little curved, and the cavity funnel-shaped, the sub-pubic angle being only 30I°. The bones were not rickety. The organs of generation, both internal and external, %%ere infantile. The measurements and appearance of this pelvis are contrasted by that author with those of the dwarf previously described. The arrest of development seems to have taken place in the present case at a period long before the changes of puberty, as shown by the undeveloped genital organs; so that the cases differ only in the degree of immaturity. Such cases as the latter are not likely to require the aid of the accoucheur.
In accouchements at a premature age, how ever, some of the yet-remaining peculiarities of the infantile pelvis may present difficulties in parturition, amongmh ich the contraction of the diameters, if not their want of adult propor tions, will be the chief. At the period of puberty, the transverse and oblique diameters enlarge much more rapidly, in the female, than the antero-posterior, and begin to preponderate over them, while, at the sante time, and in a great measure in consequence, the pelvis begins to assume its adult " standard" appearances. The full developtnent of size, however, is somewhat later in being accomplished, and depends upon the completion of the ossifi cation. These changes of the pelvis take place, as explained.by Mr. Shaw *, somewhat later than those of the upper parts of the body, in the transition from the infant to the adult state, but proceed to a greater extent, so as to reverse the excess in proportionate size from the upper to the lower extremities. The pelvic growth and the developments of puberty inay, according to the same authority, be retarded to a later period than the usual age, fourteen years, by a weakly constitution or rickets ; and the female, adult in age, still remains infantile in pelvic development. In a case mentioned by De &emery 4., the three parts of the innominate bone were distinctly separate in a female at so late an age as seventeen years. Some remarkable cases of extreme mobility of the pelvic bones in chil dren are also related by Deventer.