These are best appreciated in the small joints of the hand. Osteoarthritis has an affinity for _terminal_ joints—the so-called Heberden’s nodes. Another favourite site is the carpo-metacarpal joint of the thumb, while the preference of gout is for the metacarpo-phalangeal joint thereof and for the same articulation in the other digits. The overlying skin, as a rule, is unchanged, and never assumes, as in gout, a dusky red or purplish hue. The margin of the articular surfaces, instead of being smooth and rounded, is broken and irregular, its nodular contour being due to osseous outgrowths studding the line of junction of the bones entering the articulation.[42] In this respect they contrast with tophi, which are located near to, but not at, the level of the joint fissure. Again, unlike tophi, bony outgrowths are fixed, immutable, undergoing no change save in the direction of progressive enlargement. While the tendency of an osteoarthritic joint is to expand and increase, still the enlarged and gnarled joints never attain the colossal bulbous appearance presented by inveterate examples of tophaceous gout. RHEUMATOID ARTHRITIS This affection differs from the foregoing disorder as well as gout in that it is most commonly met with in persons under forty years of age. Moreover, it attacks women much more frequently than men. Of polyarticular distribution, it evinces a marked tendency to symmetrical invasion. Like gout, it has a pronounced preference for the smaller joints, while, similarly, it avoids the hip and shoulder. Constitutional symptoms are conspicuous: pulse quickened, temperature raised, extreme wasting not uncommon. Intense and widespread muscular atrophy with contracture is a prominent feature, also trophic disturbances of varied nature and degree. LOCAL CHARACTERS OF JOINT SWELLINGS In early stages the skin over the joint is waxy white or semi-asphyxial in tint, outline of joint smooth, rounded, and spindle in shape, with, as a rule, no irregular bony projection at the level of the articulation. If seen at a later stage, the swollen joint will be found shrunken from atrophy of all the articular structures as well as the skin. Ultimately it becomes reduced even below its normal size, the small “end-joint” of atrophic or rheumatoid arthritis. The deformities due to muscular spasm are usually in the direction of luxation and hyperextension, and differ from those of gout and osteoarthritis, in which there is more generally lateral displacement. NERVE ARTHROPATHIES