DISEASES OF BONES AND JOINTS - more important points with reference to diseases of the joints have been already mentioned (Chap. V., § 4), and it is only in their relation to rheumatism that they can become the subjects of medical diagnosis. Their local management is referred to the department of surgery, and probably for this reason they are not regarded as legitimately belonging to the practice of medicine : but in fact they are almost invariably associated with depraved constitutional states, and must be met by remedies addressed to the system at large ; in this view much of the knowledge regard ing their treatment must spring from an acquaintance with the characters by which these conditions are recognized.
In very many cases the disease which has become located in thejoint, from whatever cause it may have been originally de rived, is beyond the aid of remedies: structures have been removed, or materially altered in their minute organization, and new forma tions have been added, which can no longer be modified by treat ment suited to the primary disease ; even surgery is unable to offer any material relief. These changes sometimes serve as land marks by which we are enabled to define more exactly the nature of a subsequent attack. We recognize gout by its tophaceous deposits, as they are called; rheumatic gout by chronic thickening of the.ligaments and distortion of the joints; and we feel greater certainty that the case is one of simple rheumatism when all traces of previous suffering have disappeared: in cases of repeated seizures, the symptoms tend to become less and less distinctive of the special malady, and to present a certain similarity of cha racter.
Inflammation of bone, whether ending in suppuration or in necrosis or caries, belongs entirely to the surgeon, because local treatment and operative interference are constantly demanded. Periostitis, according to its origin, is regarded either as medical or surgical. It often has a distinctly rheumatic character : but it is still more frequently syphilitic. It consists of a local enlarge ment on the surface of the bone, tense and tender, very generally smooth, but sometimes also irregular, interfering more or less with voluntary motion, because of its relations to the origin or insertion of muscles, but not hindering passive movement, unless its position be in close proximity to the joint; these characteristics point very plainly to periosteal inflammation. When the acute stage is past,
or when the affection has come on more gradually, the thickening and induration may be accompanied by very little pain. Its rela tion to secondary syphilis is so constant that the discovery of nodes is very often sufficient to guide our determination in an obscure case : their most common situation is on the front of the tibia, and next in frequency over the cranium.
In all affections of the bones and joints in which motion is interfered with, we have to bear in mind the remarks already made upon posture and gait, and upon active and passive motion : these modes of examination serve to point out the various conditions of stiffness or immobility, of pain produced by the muscular effort, and of pain 'produced by the motion of diseased raw faces on each other, or by the stretching of inflamed ligaments; distinguishing them from muscular paralysis. Loss of power is the usual complaint of the patient, when the condition consists really of inability to use the power which exists.
Rachitis is essentially a disease of childhood, and is only known by the deformities, whether permanent or transient, to which it gives rise. In middle life, somewhat analogous effects result from mollifies ossium, though pathologically the diseases are differ ent; in the one the bones bend but do not break, in the other there is generally a great tendency to spontaneous fracture. True fragility, fragilitas °alum, as it used to be called, is, on the other hand, more closely allied to atrophy, and is very generally a disease of old age, when the absorption of tissue exceeds its re production.
In rickets and in mollifies maim the earthy constituents of bone are dimin ished, but their different characters are caused by the circumstance that in one the bone-earth is not *waited in sufficient quantity to meet the requirements of growth, in the other it is removed after its deposition, ant is replaced by morbid structure : the one is rather a consequence of faulty nutrition, the other is the effect of actual disease. In atrophy the fibrous material is re moved as well as the lime; and hence, while in mollifies the remaining portion of earthy structure is crushed and splintered by the bending of the bone, in fragilitas the bone itself breaks across.