Treatment.
—Clavicular dislocations yield fair results to intelligent treatment. Ideal results are difficult to secure without coöperation on the part of the patient. Functional results, however, are usually satisfactory.
DISLOCATIONS OF THE SHOULDER-JOINT.
The upper end of the humerus is attached to the margin of the glenoid cavity by a capsule which has a certain degree of elasticity, and which resembles a short section of a sleeve or a cuff. It is sufficiently loose to permit a wide range of motion, and were it not for the acromial process above it there would be as much motility in the upward direction as in any other. It is not the capsule which keeps the articular surfaces together, but the tension of the muscles which are wrapped around the shoulder-joint, all of which contribute to this effect. The glenoid cavity is made a more complete socket by a fibrocartilaginous rim. Thus a certain degree of subluxation or displacement may be permitted without very serious damage to this rim and capsule, but a complete dislocation is hardly possible without more or less laceration. The prominence and exposure of the joint and its natural freedom of motion help to account for the fact that more than half of all dislocations occur here, and that this rarely ever occurs in children or in the aged, in whom the violence which may be expanded produces either epiphyseal separations or fractures of the surgical neck. The relation of structure to function also accounts for their far greater frequency (i. e., four to one) in men than in women. The influence of atmospheric pressure should not be forgotten, as in the shoulder this affords a force of some fifty pounds, and in the hip of nearly double that amount, of pressure.
Fig. 341
Subcoracoid.
Subclavicular.
Subspinous.
Subglenoid.