OSTEOMALACIA. 5^5 



given while it is being carried out. Of course, institutions where 

 some particular plan of treatment is not followed exclusively, or with 

 partiality, but where all the aids of orthopaedia are employed, and es- 

 pecially where the general health of the patient is attended to, should 

 be preferred to others. 8 



OHAPTEE VII. 



OSTEOMALACIA. 



ETIOLOGY. In osteomalacia, bones which have been hard become 

 soft from reabsorption of the salts of lime, to which they owed their 

 hardness. This explanation of the disease at once shows its difference 

 from rachitis, where the lime-salts do not disappear from the bones, 

 but have never been deposited there. The immediate causes of the 

 solution and reabsorption of the salts of the bones in osteomalacia are 

 obscure. The hypothesis, that the appearance of an acid in the tissue 

 of the bones lies at the root of the processes by which the phosphate 

 of lime is dissolved, is refuted by Virchow, who found the gelatin es- 

 caping from fresh osteomalacic bones was of alkaline reaction. There 

 is a great deal in support of Virchovfs theory that osteomalacia is, per- 

 haps, to be classed among the parenchymatous inflammations where 

 no interstitial exudation is deposited, but where the inflammatory dis- 

 turbances of nutrition affect the tissue-elements of the affected organ. 

 The rarefaction, the porous, spongy, or areolar condition of these bones, 

 which are perfectly analogous to the changes in osteitis proper, the 

 frequent occurrence of the disease in the puerperal state, its customary 

 origin from the pelvis, which has been injured during parturition, and 

 lastly, the severe pain accompanying it, render it very probable that 

 osteomalacia is of an inflammatory nature. This is a rare disease ; up 

 to the present time it has been observed almost exclusively in women. 

 The exciting causes are unknown ; we only know that the first signs 

 of it, in most cases, appeared some time after confinement, so that 

 pregnancy, parturition, or the puerperal state, undoubtedly have much 

 to do with its etiology. 



ANATOMICAL APPEAKANCES. In osteomalacia, the bones become 

 very porous ; in the spongy substance, the trabeculae decrease in num- 

 ber, and disappear ; hence the medullary cavities coalesce, and in the 

 long bones induce enlargement of the medullary spaces ; in the com 

 pact cortical substance, also, the vascular channels increase, and fonc 

 areolse, which unite and change the cortical substance also into a coarse, 

 meshed, spongy tissue. Finally, in the highest stage of the disease, 

 the soft, flexible bone, which may be readily cut, consists only of 



