PELVIS. 



189 



pubic rami being approximated at the angular 

 bend to f of an inch. 



In a case which was operated on by Dr. 

 Hasbeke, and described in U Experience 

 (No. 140.), the inferior pelvic outlet was 

 nearly closed up entirely, the ischial tube- 

 rosities being approximated to within two 

 lines only, and the coccyx and pubes admitting 

 only one finger between them.* 



In Mr. Kinder Wood's case, the deformity 

 was rostrated, the most available space at the 

 brim being a circle of 1 inch diameter to the 

 left of the projecting promontory. The antero- 

 posterior diameter was 1 inch, but less than 

 f of an inch when the soft parts were at- 

 tached, f 



A somewhat remarkable variety of the ros- 

 trated pelvis is figured by Dr. Churchill (Jig. 

 1 1 9.). In this pelvis the superior pubic ramus 



Fig. ] } 9. 



Oblong rostrated pelvis. (After Churchill.) 



is bent at its centre, so as to be nearly ap- 

 proximated to the opposite pubis at that 

 point, and the symphysis projects in a rostrum. 

 The upper part of the sacrum and the pro- 

 montory is, however, thrown back, the coti/lo- 

 sacral arch spread out, the antero-posterior 

 diameter increased, and the transverse lessened, 

 somewhat in the same manner, and, doubtless, 

 by the same mechanical conditions, modified 

 only by the yielding of the pubis, as in the 

 oblong pelvis before described. The acctabuln 

 in this pelvis are directed principally forwards 

 and outwards. 



Causes of the foregoing pelvic distortions. 

 The principal causes of the preceding partial 

 and complete distortions of the pelvis, are two 

 diseases affecting the osseous system ; viz. 

 " rickets" and '' mollities ossium" or " malacos- 

 teon." 



Rickets is a very common disease of early 

 life, which is said to be more apt to occur in 

 scrofulous children about the period of denti- 

 tion, but which may occur even after puberty, 

 according to some authors. It is characterised 



* Lancet, 1840. 



f Mod. Chir. Trans, vol. vii. p. 264. 



by a simple deficiency of the earthy matter of 

 the bones chiefly of phosphate and carbonate 

 of lime ; while the animal constituents, al- 

 though softened, and rendered less elastic, 

 retain nearly their normal composition. The 

 bones thus rendered pliable, which lie in the 

 lines of weight, pressure, or muscular action, 

 yield slowly and give way to the operating 

 forces, bending in such a manner as the re- 

 sultant direction of pressure and muscular 

 traction, c., permits them. 



We must refer the reader to the Article 

 on the PATHOLOGY OF BONE (vol. i. p. 440.) 

 for a more detailed account of this disease. 



In Rokitansky's Pathological Anatomy, the 

 bones in Rhachitismus infantalis are described 

 to present t wo separate pathological conditions. 

 In one, the bones are very vascular, soft, fragile, 

 and swollen, with enlarged medullary cavities, 

 and the areolar spaces filled with, and often 

 distended by, a pale, reddish jelly, which press- 

 ing upon the areolar partitions, produces 

 their absorption, and thus the enlargement 

 of the cavities by coalescence. This jdly 

 is also sometimes found effused under the 

 periosteum. In the second variety, the bone 

 is more or less reduced to its cartilaginous 

 elements, the corpuscles (lacunae} empty, the 

 rays obliterated, and the lamellar structure 

 wanting, or fallen asunder, with corpuscles 

 interposed between the layers. On the 

 last condition the softening of the bones de- 

 pends. The periosteum is more vascular 

 than normal, tumid, and more closely adhe- 

 rent, so as to tear off with it a portion of the 

 softened adjacent bone. It is said to differ 

 from malacosteon in not being a painful 

 disease, and in being capable of cure, with a 

 subsidence of the swelling and reabsorption 

 of the effused substance. In high degrees of 

 the disease, however, atrophy and fragility re- 

 main permanently. The osseous structures 

 affected by rickets are lighter, less marked, 

 thinner, and more porous than normal, or than 

 those affected by mollities ossium, according 

 to Naegele ; appearing as if they had been 

 steeped in weak acid. 



The analysis of a rickety humerus and 

 scapula, is given by Rokitansky as follows : 

 Phosphate of lime and magnesia - 15'60 

 Carbonate of lime - - 2'66 



Soluble salts ... 0'62 



Total of inorganic matter 

 Cartilage, vessels and fat 



18-88 

 81-12 



100-00 



In the humerus, also, was found 10'54 per 

 cent, of fat. Specific gravity of the bone, 

 0-612. 



Davy found in 100 parts from the tibia 

 of a rickety child, 74 parts animal and 26 

 earthy ; and Bostock, in a vertebra affected 

 with the same disease, 79'75 animal, and 20-25 

 earthy, in 100 parts. 



When this is contrasted with the norma 

 proportions of the osseous constituents in the 

 child, as given by Schreger viz. 47-20 parts 

 animal, and 48'48 earthy (or about one half 



