In the same Museum there is a young male adult skeleton in which this form of pelvis is also well shown. It, also, is coexistent with, and dependant on, a backward cur vature and shortening of the spine, and ex tensive ankylosis of the vertebrm in the dorsal and lutnbar regions. The lumbar ver tebrm are inclined much backward, so as to drag in the same direction upon the upper end of the sacrum ; while the upper dorsal vertebrae incline forward, so as to- bring the 1st dorsal over the centre of the pelvic circle. There is,in this case, no lateral deviation of the spinal column. The tibim and fibulm have an inward curve, indicating the existence of a softened rickety state of the bones at an early period of life.
In the Hunterian collection of pathological specimens is a young adult pelvis, numbered 3-120, presenting the same kind of deformity, accompanying the same kind of backward angular curvature and ankylosis of the bodies of the vertebrx at the same place—viz. the junction of the last dorsal and 1st lumbar. The 1st dorsal vertebra, in this skeleton, likewise occupies a position above the centre of the pelvic opening. The upper end of the sacrum is dragged backwards by the inclined lumbar vertebrm so as to increase the con jugate diameter of the brim to 4i inches. The lower end of the sacrum is tilted forward so as to bring the tip of the coccyx to within a short distance of the ischial spines. The cotylo-sacral arch is stretched out, and the transverse diameter of the brim reduced to 4 inches only. The acetabula are directed more downwards than usual, and the right iliac wing is pressed outwards by the 9th and 10th ribs, which rest on it, and the venter completely flattened out.
I find that Rokitansky has met with in stances of this oblong deformity of the pelvis, coexisting with backward angularity of the spine.
In cases of backward angular curvature low down the spine, especially where there is no lateral deviation, there will be a tendency to production of this form of pelvis, especially if the bones be somewhat softened, as they usually are in these cases ; and al though such cases of pelvic distortion are, as far as I have seen, more common in the male, yet the same cause occasionally produces this effect upon the female pelvis, and may produce obstruction during parturition, not only by the contraction of the antero-posterior diameter at the outlet, but even at the brim, by the diminution of its transverse dianzeter.
An acute angle in the lower part of the sacral curve may also produce this contraction of the inferior pelvic outlet. When this exists singly., the elevation of the coccyx is more
considerable than usual, and the axis of the in ferior plane directed more backwards. This bending upwards of the apex of the sacrum is, however, most usually seen in connection with more general pelvic deformity, and is some times accompanied by ankylosis of the sacro coccygeal joint.
In a case recorded by Mr. Bell, the antero posterior diameter of the inferior outlet was contracted to half-an-inch only, and in one of Naegele's, it was even less than this, in both entirely precluding delivery. In so great a contraction, the sacral bend must have been unusually great, or the lower end of that bone tilted forward in the manner just de scribed.
of the sacrum is more open than usual. Thus is constituted another variety of funnel-shaped pelvis, caused mainly by the gradually nar rowing of antero-posterior diameters, instead of the lateral, as in the masculine pelvis be fore described.
In the King's College Museum are the pelvis and spine of a fenzale, well exemplifying this deformity (see fig.116.). The spine is affected hy a rickety curve, the greatest extent of which is about the 6th, 7th and Sth dorsal Distortions affecting the whole pelvis. — In these cases the pubic bones are always more or less extensively implicated in the distortion, and entering, as they do, into the formation of both brim, cavity, and outlet, all these parts of the pelvis are contracted or mispropor tioned. At the brim, however, the obstruc tion usually takes place, while the operations necessary to procure delivery through the natural passages are rendered more difficult by the distortion. of the cavity and inferior opening.
General distortions of the pelvis are com monly divided into three kinds, named, from the shape of the brim, the ovate or elliptical,— the cordiform or angular,—and the obliquely ovate.
The ovate, elliptical, or reniforne pelvis. — In this distortion the sacrunz is placed almost horizontally, so that the sacralpromontory pro jects forward to a great degree, generally at the same tirae deviating from the median line, and considerably sunk in a direction forwards and downwards, so that the lowest lumbar vertebra forms the most projecting point. The lateral sacral curve is diminished, flat tened out, and often bent backwards on each side the promontory. The vertical curvature is generally diminished and flattened in some degree, and directed more downwards by the more horizontal position of the bone ; but occasionally there is an acute bend forwards at the lower part. The coccyx is generally, bent acutely forwards.