The " pelvis oblique ovata," or obliquely con tracted pelvis. This form of pelvic distortion was first distinguished and accurately described by Naegele, the distinguished Professor of Mid wifery at Heidelberg, as possessing the follow ing characteristics (see fig. 123.) 1. Complete ankylosis of one of the sacro iliac joints, with coalescence of the sacrum and ilium, generally leaving no cicatrix nor line of junction.-2. Arrest of development, contrac tion of the lateral mass, and diminution of the foramina, on the ankylosed side of the sacrum.
3. Narrowing of the innominate bone of the same side, shortening and also flattening of the linea innotninata, contraction of the sa cro-sciatic notch by the ankylosis, and con traction of the la,teral parts of the sacruin ancl ilium composing the sacro-iliac junction.
4. Shifting of the sacrum towards the anky losed side, and twisting of its anterior surface in the same direction, together with removal of the pubic symphysis towards the opposite side, so as to be no longer placed in the median line opposite to the sacral promon tory, but obliquely directed towards it ; a di rect forward line from the promontory falling on the superior pubic mums, between the symphysis and acetabulum, its distance from the former varying with the degree of distortion. The bodies of the lower lumbar vertebrm are also,more or less, turned towards the ankylosed side.-5 On the ankylosed side, the inner wall of the pelvis, both before and behind, is less excavated and flatter than in the normal pelvis. 6. On the side free from ankylosis also, the form deviates from the normal shape, although at first sight it appears healthy. On placing together the corresponding non-ankylosed sides of two of these pelves, separated at the symphysis and in the median line, in which the right and left sacro-iliac joints respectively were ankylosed, Naegele found the pubic bones widely divergent from each other. So that, on this side also, these pelves are abnormal, not only in direction, but in form also, being curved less behind and more in front, than in the normal pelvis. 7. From this it fol lows, that the obliquely deformed pelvis is contracted the diameter which extends from the normal sacro-iliac joint to the opposite acetabulum; while it is not con tracted, but sometimes, according to the de gree of distortion, even widened in the di ameter, from the anky losed joint to the acetabulum of its opposite side. The superior
pelvic aperture thus presents the appearance of an oblique oval (or oblong), the longest diameter of which corresponds to one of the oblique pelvic diameters, and the shortest to the other oblique diameter. From this ap pearance of the brim he was led to apply the name above given. That the sacro-cotyloid distance, and also that between the apex of the sacrum and the sciatic spine, is smaller on the ankylosed side than on the other. That the distances between the sciatic tuberosity of the ankylosed side, and the posterior superior iliac spine of the opposite side, and also be tween the last lumbar spine and the anterior superior iliac spine of the ankylosed side, are less than the like measurements on the oppo site side. That the distance between the lower border of the pubic symphysis and the posterior superior iliac spine, is greater on the ankylosed side than on the other. That the walls of the pelvic cavity converge towards the outlet in some degree in an oblique direc tion, and the sub-pubic arch is more or less narrowed, and turned towards the thigh of the ankylosed side. That the contraction of the sa cro-sciatic notch, and the approximation of the sciatic spines, is proportionate to the degree of distortion. And, lastly, that the acetabu lum of the ankylosed side is directed more forward than normal, and the opposite one almost directly outward. In most cases, the sciatic tuberosity, and the acetabulum of the ankylosed side, were more elevated than the opposing ones ; the ankylosed innominate bone appearing as if pushed upwards.
A remarkable peculiarity of this deformity is, that, with the exception of the difference in the side where the ankylosis had taken place, the pelves affected with it were extremely like each other. The strength, texture, and ap pearance of the bones were perfectly healthy ; there was no limping gait observed in the patients affected with it ; nor any history of accident, rickets, or malacosteon.
Examples. Naegele collected, with incre dible industry, notes of thirty-five examples of this disease in female pelves, and two in male pelves. Of these, two (one male and the other female) were in the collection of Pro fessor Montgomery, of Dublin, and the others in the various collections of France, Germany, and Italy.