On the pathological basis of the treatment of joint diseases / by Henry G. Davis, M.D.

  • Davis, Henry G. (Henry Gassett), 1807-1896.
Date:
1862
Catalogue details

Licence: Public Domain Mark

Credit: On the pathological basis of the treatment of joint diseases / by Henry G. Davis, M.D. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    extend the limb, the motion is communicated to the part beyond, in a similar manner as when the joint is anchylosed. This immobility in some cases may be in part produced by the tumefaction accompanying the inflammatory process; but tumefaction is not necessary to the result, for in the very cases of chronic morbus coxarius where no swelling exists, the immobility is most marked. Anaesthesia has been produced in these cases without relieving the fixed state of the joints; yet that there was not true anchylosis, was proved by the perfect freedom of motion after a few days of treat- ment by elastic extension. Again, in a limb with disease of the hip-joint that has been under treatment until it will admit of flexion and extension readily if moved gently, yet if handled a little roughly, all the muscles will be upon their guard, and the pelvis will be found following every motion of the femur. If it is true that the diseased joint is held in a fixed position by a certain rigidity of the muscles passing to or beyond it, an amount of pressure corresponding to the contractile force of the muscles, as then exerted, must be produced upon the articulating surfaces of the joint. The inquiry may be made—Does not the'joint in health sustain a much greater amount of pressure with impunity? To answer this question, let us examine a particular point in the mechanism of cer- tain joints, of which the knee furnishes an example. The lower por- tion of the femur terminates in two condyles, each of which presents an articular surface, narrower, but at the same time more extensive, antero-posteriorly than the corresponding articular surface of the head of the tibia. Not the whole, therefore, but only a part of the articular surface of the condyle can be in contact with that of the tibia at any moment; and the precise portion in contact varies with every varia- tion of flexion and extension of the knee-joint; this will be evident, when we consider that the concave surface of the head of the tibia and the convexity of the condyles of the femur do not correspond. When the limb is in exercise, or when its position can be frequently changed, no difficulty arises from the contact and pressure, because then the point of pressure is constantly changing, and when not in exercise, its position is altered whenever any inconvenience is experi- enced. In health, therefore, the pressure is never exerted upon any one point for a great length of time continuously, but is ever changing from one part of the whole surface to the other. It is for this reason that a joint in health can suffer the weight of the body to rest upon it without injury; but when the parts are