The ilia and ischia on each side are often removed to a greater lateral distance than normal. The iliac wings are flattened and directed more forward ; and the cotylo sacral arclz is more sharply curved, and often shorter and thicker than normal. The planes of the ischia diverge instead of slightly con verging downward ; the 'spines and tuberosities being likewise divergent, and the latter di rected more outwards and backwards. The superior rand of the pubes are generally flat tened out, having little anterior projection ; while the inferior ranzi are widely divergent, affbrding a wider and shallower expansion of the sub-pubic arch. In some cases, however, the sub-pubic arch is little altered.
In some instances the symphysi.s of the pubis presents the appearance of being in dented or pushed backwards, giving an out line to the brim of an hour-glass shape.
The diameter principally diminished is the conjugate of the brim, and often one or other of the oblique diameters. In one variety the transverse diameter of the brim is also con tracted. The transverse diameter is, however, sometimes undiminished, or even increased. The transverse diameter of the inferior outlet is generally most considerably increased ; but the antero-posterior diameter is most usually con tracted by the bend in the sacrum. In many instances, however, it is considerably enlarged. The depth of the true pelvis is generally dimi nished, and its capacity lessened.
The sacro-vertebral angle is generally much diminished, from the backward horizontal di rection of the upper end of the sacrum.
The inclination of the superior plane is some times increased so much as to be vertical ; the axis of the brim being generally directed more forward than in the " standard," and that of the inferior outlet more backward. Some times, however, they are very little altered.
The structure of the bones is light, slender, and fragile, indicating the origin of the dis tortion in rickety softening.
Exanzples of this kind of pelvis are nu merous. One of the most well-known is that of Elizabeth Sherwood, who was delivered by Dr. Osborne by means of the crochet. The measurements of this pelvis are given as fol lows:—From the most prominent point of the lumbar vertebra to the upper border of the pubic symphysis, inch. From the same point on the left side to the left pectineal eminence, If inches. The same measurement on the right side, I; inches. From the sacral promontory to the pubic symphysis, 11 inch. Transverse diameter of brim, 5 inches. Left
oblique ditto, 4i inches. Right oblique, 41 inches. Antero-posterior of cavity, 2i inches. Transverse ditto, 5 inches. Antero-posterior of outlet, 21 inches. Transverse, 41 inches. Sub-pubic angle, 100°.
The measurements of a very extreme ca.se of this kind of distortion are recorded by Dr. Rarnsbotham (seefig. 117.) as follows :— Conjugate or sacro-pubic diameter of brim, t of an inch only. From right side of sacral promontory to right pubis, 11 inch. The same measurement on the left side, 1-1 inch. Antero-posterior diameter of outlet, 2 inches. Transverse diameter, 41 inches. The shape of the brim in this pelvis is hour-gla.ss, the pubic symphysis being pushed back. Such a pelvis, in the opinion of the above-named writer, would necessitate the abdominal section.
In a less extreme case, given by the same writer, the sacral promontory and lumbar curve bend much more considerably towards the left side. At the brinz, the conjugate dia meter is 14 inch ; the right sacro-pubic, 2 inches; the left, / of an inch only. The transverse diameter, measured in the lateral curve of the brim, 61 inches. At the inferior outlet, the antero-posterior, 41 inches ; the transverse, 51. In the figure of this pelvis given by the author, the long axis of the sacrum is represented as placed obliquely across the median line, its apex inclining to the right side; while the tuberosity of the right ischium is widely divergent, principally causing the increase of the transverse dia meter of the outlet. The left ischial tube rosity and acetabulum are brought more under the line of gravity. The left superior pubic ramus is thus pushed nearer to the promontory than the right, causing a slight twist in the pubic symphysis. In this pelvis the author considers that delivery might be effected " per vias naturales," by craniotomy.
In one of Dr. Hull's cases, that of Ann Lee, affected with this deformity, the con jugate diameter I‘vas reduced to 11 inch, and the sacro-cotyloid on each side equal, and measuring I 1.9w inch. The transverse diameter, in its widest part, amounted to 41 inches only. There was little flattening of the pubes, the contraction being produced chiefly by the projection of the sacrum, the chief bend being near the sacro-iliac joints. The distance between the antero-superior iliac spines was only Si inches, but the dimen sions of the cavity and inferior outlet were not materially ditninished.