PELVIS. 



187 



bend at the lower lumbar vertebras, the 

 sacrum is placet! horizontally backward, and 

 the sacro-vertebral angle diminished 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 diameters. 

 With the exception of the last-named pecu- 

 liarities, 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 

 measure projecting forwards, yet is more 

 clecidedlv 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 almost 

 bent double. The coccyx is generally placed 

 horizontally. 



The ilia and ischia on each side are 

 pushed together upwards and towards the 

 sacrum, so that the acetabula are thereby 

 approximated and placed nearer to the 

 sacral promontory. The cotylo-sacral arch 

 presents, in most instances, a very sharp 

 curve near the sacro-iltac joint, and is 

 often bent double, so as to offer a mere chink 

 between the sacral and iliac portions. The 

 iliac wings are generally approximated, the 

 venter being sometimes doubled into a mere 

 fissure, and the crest being curved inwards 

 more than normal, so as to bring the anterior 

 superior iliac spines nearer together; while 

 the posterior extremity of the crest, or iliac 

 tubero$ily y is bent inwards and forwards over 

 the sacrum, by the weight of the body, acting 

 through the sacro-iliac ligaments. The planes, 

 spines, and tuberosities of the ischia are pushed 

 inwards towards each other, and sometimes 

 turned more upwards, so as to cause a chink 

 or acute bend in the ischial plane, passing 

 downwards and forwards, and which has been 

 compared by Naegele to the fold made by 

 bending pasteboard. The superior rami of 

 the pubes are directed horizontally forwards, 

 being almost, and, in extreme cases, quite pa- 

 rallel to each other anteriorly. 



This alteration in the direction of the 

 pubic bones takes place, in many cases, by 

 an inward curve in the acetabula at the 

 point of junction of the three pieces of the 

 innominate bone, as indicated by the ilio- 

 pectineal eminence, and the form of the brim 

 will then assume the shape of the letter Y 

 when the deformity is great. In many in- 

 stances, however, the superior pubic rami 

 are bent inwards at an obtuse angle, in the 

 centre, just above the obturator foramina, the 



bones of the opposite sides almost or entirely 

 meeting at the angle, and continuing parallel 

 with each other to their articulation. The 

 form of pelvis resulting from this bend in the 

 superior pubic ramus has received more par- 

 ticularly the name of the cocked hat or ros- 

 trated pelvis; the latter name being applied 

 from the beak-like projection of the pubis at 

 the symphysis. It is markedly distinguished 

 from those" angular deformities in which the 

 inward bend of the innominate bones takes 

 place at the acetabular junction of their three 

 component pieces, and is found exemplified 

 in most of the specimens exhibiting the 

 greatest contraction of the diameters. 



The pubic symphysis is, in every case, more 

 or less folded back, straining upon the anterior 

 ligaments. The bending, however, is seen to 

 occur in the osseous portions of the articula- 

 tion forming the pubic angles, generally about 

 the position of the pubic spine, and it is much 

 more considerable in the cases where the an- 

 terior portions of the pubes are parallel to 

 each other. The sub-pubic arch is, in all 

 cases, very considerably narrowed by the 

 parallel position of the superior pubic rami 

 and the approximation of the ischial tu- 

 berosities. In many instances, the latter 

 appear to be pushed forwards and upwards, 

 so that the contraction of the sub-pubic arch 

 is greatest at the ischial rami, just above the 

 tuberosities, above which point the sides of 

 the arch bulge outwards. In the rostrated 

 pelvis, it is often completely obliterated or 

 transformed into a mere chink. The acetabula 

 are elevated and turned more forwards than 

 normal, and in many examples of rostrated 

 pelvis are directed almost quite anteriorly. 



The angles of both the superior and inferior 

 pelvic planes with the vertebral column are 

 lessened. In a case given by Naegele, the supe- 

 rior plane was at right angles to the spine. 

 The axis of the brim is thus rendered more 

 vertical, and that of the outlet more forward, 

 than in the standard pelvis. The superior 

 plane is often bent into two by the elevation 

 of the acetabula, but, in some instances, the 

 pubic symphysis is pushed upwards above the 

 acetabula. 



The diameters are all contracted in a greater 

 or less degree, those of the brim most ex- 

 tensively. In this kind of pelvis occurs the 

 greatest diminution of diameters of all the re- 

 corded examples. The diminution, however, 

 is such, that if the irregular form were re- 

 shaped, the diameters would be replaced, 

 i. e. there is no absolute shortening of the 

 bones, or not so much as in the rickety pelves. 

 Examples. The pelvis of Isabel Redman 

 {fig. 118.), upon whom hysterolomy was per- 

 formed by Dr. Hull in 1794, and which is said 

 to present at the brim the most contracted 

 diameters on record, is affected by this de- 

 formity in its rostrated form to such an extent, 

 that a ball Jf inch in diameter would not pass 

 through it at any part. 



At the brim, the 4th lumbar vertebra was 

 completely sunk into the pelvis, and in- 

 clined to the left side, and its distance from 



