REPORT

ON A

NEW PRINCIPLE OF DIAGNOSIS IN DISLOCATIONS

OF THE

SHOULDER-JOINT.

BY

L. A. DUGAS, M.D.,

PROF. OF SURGERY IN THE MEDICAL COLLEGE OF GEORGIA.

REPORT ON A NEW PRINCIPLE OF DIAGNOSIS IN DISLOCATIONS OF THE SHOULDER-JOINT.

HAVING for a number of years inculcated in my lectures the principles contained in this paper, I was requested to reduce my views to writing, for the benefit of our classes, and accordingly published an article on the subject in the March number, for 1856, of the Southern Medical and Surgical Journal, p. 131. The object of this communication is to present the American Medical Association with a brief exposé of this interesting subject, and to accompany my remarks with pictorial illustrations, calculated to impress the eye as well as the understanding of the reader.

The principle of diagnosis to which I refer may be enunciated in the following language: If the fingers of the injured limb can be placed by the patient or by the surgeon upon the sound shoulder, while the elbow touches the thorax, there can be no dislocation; and if this cannot be done, there must be a dislocation. In other words, it is physically impossible to bring the elbow in contact with the sternum or front of the thorax if there be a dislocation; and the inability to do this is proof positive of the existence of dislocation, inasmuch as no other injury of the shoulder-joint can induce this inability.

In order to make these propositions apparent, I beg leave to present drawings taken from the skeleton, showing the relative position of the bones in the natural state, and in the several dislocations of the shoulder. The evidence thus obtained in support of my principle, would be still stronger if the bones were invested with their normal coverings and attachments.

Let us then look at Fig. 1, and we may observe, that while the head of the humerus occupies the glenoid cavity, and the fingers rest upon the other shoulder, the elbow and lower end of the humerus lie upon the thorax without difficulty, because of the circumstance that the head of the humerus, when in its natural position, is removed several inches from the ribs. In consequence of

the rotundity of the thoracic walls it is physically impossible that both ends of the humerus should at the same time come in contact

with the chest. We see, therefore, in Fig. 1, that in the absence of any dislocation, the upper half of the bone does not touch the thorax, and that the lower half does so without the least difficulty.

shoulder, the elbow is forced so far forwards that it cannot touch the thorax. In this state of things, the upper end of the humerus alone touches the ribs, while the lower end is proportionately removed from the chest. Any attempt to force the elbow against the thorax must be fruitless, unless at the expense of a disruption of all the soft parts by which the head of the humerus is held down; for, as I have already stated, it is physically impossible for both ends of the humerus to touch the thoracic walls at the same time.

We have represented, in Fig. 3, a dislocation forwards or below

the clavicle; and here again we find the upper end of the humerus resting upon the ribs--the elbow being consequently removed from the chest. The upper half of the humerus touches the thorax, and so long as this is the case, it is physically impossible for the lower portion of the humerus also to do it. In dislocations of this kind, it is very difficult to carry the fingers upon the opposite shoulder, even though the elbow be allowed to project forward, because of the resistance offered by the strong muscles which pull back the humerus. I have, however, represented the bones of the skeleton. in this position, for the purpose of showing the effect, in case it could be assumed, in the living subject.

Dislocations of the humerus upon the dorsum of the scapula, although very rare, should still be carefully studied. I have, there