PELVIS 



1037 



PELVIS 



column. P. major, the false pelvis. P., Malacos- 

 teon. Synonym of P., Osteomalacic. P., Mascu- 

 line. See P., Pitnnel-shaped. P. minor, the true 

 pelvis. P., Naegele's Oblique, a pelvic deformity 

 with ankylosis of one sacro-iliac synchondrosis, lack 

 of development of the associated lateral sacral mass, 

 and other defects that distort the diameters and render 

 the conjugate oblique in direction. P. nana, a dwarf 

 pelvis. P., Obliquely Contracted. Same as P., 



Figure-of-eight Rachitic Pelvis. 



VcegeWs. P., Obliquity of, called, also, the Inclin- 

 ation, the angle between the axis of the pelvis and 

 that of the body. P., Obstetric, the static pelvis 

 plus the last lumbar vertebra. P., Osteomalacic, 

 a distorted pelvis characterized by a lessening of the 

 transverse and oblique diameters, with great increase 

 of the anteroposterior diameter. It is due to morbid 

 softening of the bones. P., Outlet of. The inferior 

 opening of the pelvic canal. P., Planes of, imagin- 

 ary surfaces touching all points of the circumference. 

 The plane of pelvic expansion perforates the middle of 



Reniform Rachitic Pelvis 



the symphysis, the tops of the acetabula, and the sa- 

 crum between the second and third vertebrae. Its an- 

 tero-posterior diameter is 12^" cm., its transverse di- 

 ameter 1 2 ' < cm. The plant of pelvic contraction passes 

 through the tip of the sacrum, the spines of the ischia 

 and the under surface of the symphysis. Its antero- 

 posterior diameter is 1 1 '^ cm. ; its transverse diameter 

 io>£ cm. P., Pseudo-osteomalacic , a pelvis de- 

 formed by rickets, resembling that caused by osteo- 

 malacia. P., Rachitic, the distortion produced by 

 nckets, usually consisting in a sinking in and forward 

 of the sacro-vertebral angle, with a flaring outward of 

 the iliac crests and increased separation of the iliac 



spines. P., Reduced, a generally contracted pelvis ; 

 a justo-minor pelvis. P., Reniform, one in which 

 the inlet is kidney-shaped. P., Robert's, one in 

 which there is an ankylosis of both sacroiliac joints, 

 with a rudimentary sacrum, both lateral sacral masses 

 being undeveloped, and other malformations, the 

 oblique and transverse diameters being much narrowed. 



Transversely Contracted Pelvis of Robert. 



P., Rostrated. Synonym of P., Beaked. P., Round, 

 one in which the inlet is almost round in outline, owing 

 to a diminution of the difference between the conju- 

 gate and the transverse diameter. P., Rubber. 

 Synonym of P., Osteomalacic. P., Scoliotic, a 

 distorted pelvis caused by lateral curvature of the 

 spine. P., Simple Flat, one in which the only de- 



Rostrated Malacosteon Pelvis in Early Stage of 

 Deformity. 



formity consists in a shortening of the anteroposterior 

 diameter. P., Small. See /l, True. P. spinosa, a 

 rachitic pelvis in which the crest of the pubis is very 

 sharp, and presents a spine at the insertion of the parvi 

 psoas. P., Split, a form in which there is congenital 

 separation of the pubic bones at the symphysis. It is 

 often associated with exstrophy of the bladder. P., 

 Static, the bony pelvis, called, also, the P. , Anatomic. 

 P., Straits of, superior and inferior, the planes of 

 the inlet and outlet. P., Superior. See P., false. 

 P., Transversely Contracted. Same as P., Rob- 

 ert 's. P., Triangular, one with a triangular inlet. 



