36 OF THE PELVIS. 



at the supenor strait, less common at the perineal strait, and met with 

 still less" frequently in the excavation; it may affect the antero-pos- 

 terior, transverse or oblique diameters, either taken separately, or 

 several of them conjointly. 



85. According to my researches I find that it most frequently 

 affects the oblique diameters of the superior strait, and more generally 

 one than both of them at once; shortening of the transverse dia- 

 meter is the rarest of all, and has perhaps never been met with 

 alone. 



86. These different deformities give to the entrance of the pelvis 

 forms as various as they are easy to conceive of. Shortening of the 

 antero-posterior diameter may depend on too great a saliency of the 

 sacro-vertebral angle, and then the strait is cordiform, if, at the same 

 time, the symphysis of the pubis is driven backwards, the pelvis 

 exhibits the appearance of the figure go, lying in a horizontal posi- 

 tion. When both of the oblique diameters are affected, the bodies 

 of the pubis, by approaching the promontory, may, if there be no 

 derangement of the symphysis, give to the strait the shape of a tri- 

 angle, a trapezium, or a trefoil, according as the ends of the bis-iliac 

 diameter shall form angles more or less acute or rounded. These 

 pelves, which have been denominated trilobaled or trifoliated, also 

 present this peculiarity, that the three segments are sometimes 

 equal, while at other times the anterior portion, or the right, or left, 

 is much smaller than the other two. It may also happen, that the 

 two acetabula may tend to approach each other, in proportion as 

 they approximate towards the sacrum; the pubes in this case, bent 

 at a right angle to the ileo-pectineal eminences, project from one 

 inch and a half to two inches in front, become parallel to the antero- 

 posterior diameter, and have between them a space of only a few 

 lines. The figures of two pelves of this sort may be seen in a dis- 

 sertation by Weideman. Madame Boivin has given a design of one 

 that belongs to the same category; but the most extraordinary one 

 is that belonging to M. Jeuffrion, and a model of which in plaster 

 was deposited by M. Maygrier in the Museum of the Ecole de Me- 

 decine. In this pelvis the two pubes proceed directly backwards to 

 the points where they unite with the ilia, that is, to the extent of a 

 full inch and a half; near the acetabula, as well as immediately behind 

 the symphysis, the interval between them is only three lines; all 

 this portion, therefore, is completely foreign to the circle of the 

 strait, and the antero-posterior diameter measures in reality only two 

 inches and a half, instead of five, as would have been supposed had 

 it been measured externally during life. 



87. When only one of the oblique diameters is deformed, it com- 



