In describing the static diseases of the joints the author starts out with the assertion that each extremity, upper as well as lower, forms a static unit and that any static disturbance affecting primarily only one joint or one bone must have its effect extended to all of the bones and joints of that extremity. The primary change consists in an incongruence of the joint-surfaces, either of an anatomic or of a habitually functional nature. A joint becomes incongruous, as the author terms it, when, as for instance, in a hip a part of the cartilaginous surface at the head of the femur, as a result of pathologic or habitual rotation changes, fails of contact with the cartilaginous surface of the acetabulum. When such a condition exists in any joint for a sufficiently long time serious consequences follow.
The author considers the above as the basis of those changes which