In Mr. Thomson's case of Ctesarian section, the pelvis was affected with this deformity. The normal lumbar curvature was so much increased, together with the pelvic inclination, that the sacrum was placed quite horizontal, and the superior plane directly vertical, and its axis consequently parallel with the hori zon; but with little or no lateral deviation of the sacral promontory. The legs were crooked, and the acetabula faced directly forwards. The conjugate diameter of the brim was diminished to 1 of an inch ; the transverse was a'oout 5 inches, and the inter sciatic apparently about 41.* Dr. Robert Lee gives the dimensions of a case of ovate deformity in which the patient, after being delivered by craniotomy at an early period of pregnancy in the first labour, died in the second from rupture of the uterus. The conjugate diameter of the brim was 2 inches 1 line; the transverse, 5/ inches. At the outlet the distance between the sciatic tuberosities was 41 inches ; between the tip of the coccyx and lower border of the pubic symphysis, 31 inches. This obstetrician con siders that if, in this case, premature labour had been induced at or before the fifth, in stead of the seventh month, the patient might have been saved.t It has been said that in pelves presenting the ovate deformity from rickets, the contrac tions of the diameters of the brim are generally accompanied by the enlargement of those of the outlet, and the numerous examples of enlarged transverse diameters of the outlet, in particular, are adduced.
In an ovately deformed pelvis in the Museum of King's College, however, in which the con jugate diameter of the brim is 2 inches, and the transverse also contracted to 4/ inches ; at the outlet the inter-sciatic diameter is contracted to as little as 3/ inches, and with it the sub pubic angle is diminished also, while the antero-posterior is increased to 4/ inches. This pelvis is remarkable for the great flat tening of the sacrum, the anterior surface of which lies almost in a straight line, in which direction the coccyx also is nearly placed. The antero-posterior diameter of the cavity is thus reduced to 3/ inches. The distance between the ischiai spines is, however, 4 inches. The sacral promontory projects more forwards than downwards, and the lumbar curve is inclined to the left side. In this pelvis the brim is contracted considerably in all its diameters, and this contraction is evidently produced by tbe crushing down wards of the sides of the cotylo-sacral arch. The length of the cotylo-sacral rib on the right side, taken froni opposite the ilio-pec tineal eminence to the sacro-iliac angle along the curve, amounts to only 11 inch, while the direct measurement is reduced to 11 inch. The rib of bone is at the same time much increased in thickness, presenting an almost cubical mass between the cotyloid and sacro iliac articulations. On the lett side, the direct
measurement is a little more.
In the table of measurements of diseased pelves given by Dr. Murphy, the transverse diameter of the brim in the five ovate pelves amounts to 5 inches only in two cases, and in a third, it is diminished to 41 inches. In many of these cases we may conclude that the cotylo-sacral rib was shortened as well as bent backward. The transverse diameter of the inferior opening is not enlarged in all the above-mentioned cases. In one it amounted only to 31, and the sub.pubic angle (mainly depending on this diameter) is only 70°. The antero-posterior diameter is, in three cases, increased to from 4 to 41 inches, while in the remaining two cases it is diminished to 2} and 21. These latter measurements, doubtless, depend in great measure upon the position of the coccyx, or, as in the case above given from the Museum of King's Col lege, upon the flatness of the sacrum, or in its bend. They show, however, that the en largement of the inferior diameters in not uni versally characteristic of the general ovate deformity. We may also conclude that the general contraction of the diameters of the brim, which is often found in these pelves, is produced mainly by the shortening of the cotylo-sacral rib of the ilium in the line of pressure, without any eversion of the lower part of the innominate bones.
A singular pelvic deformity, related in some degree to this class, is represented in Moreau's plates, in which, by an anterior bend at the lower lumbar vertebrm, the sacrum is placed horizontally backward, and the sacro-vertebral angle dirninished to rather less than a right angle. The effect of this is to increase the obliquity of the innominate bones, and the distance from the sacrum to the pubis, to approximate the pubis and coccyx, and to widen the transverse cliarneters. With the exception of the last-named peen harities, this pelvis presents the condition and appearance of that of a quadruped, in being placed horizontally; the trunk, however, being kept in the vertical position by the re markable sacro-vertebral bend.
The cordiform or angular pelvis. — This distortion presents wide differences to the kind just described.
The sacral promontory, though in some rneasure projecting forwards, yet is more decidedly sunk down below its proper level into the cavity of the pelvis, with an in clination to one side of the median line, in most cases to the left. The lateral masses of the sacrum are likewise bent back, alter ing the outline of the lateral sacral cur vature. The vertical curvature of the sacrum is also increased to a great degree ; the hollow of the sacrum, in many cases, being ahnost bent double. The coccyx is generally placed horizontally.