Among these authors we find Sir A. Cooper, who, in his description of the acci dent called by him " partial luxation of the shoulder joint, forwards and inwards, to the coracoid process," gives a case which he sup posed to be one of this accident, and relates the symptoms to teach us how it may be re cognised ; but for its anatomical characters he refers to an example found in the dissecting room, the history of which was unknown. He says, " The only dissection of this accident which I have had an opportunity of seeing was the following, for which I am indebted to Mr. Patey, surgeon in Dorset Street, who had the szibject brought to him for dissection at the anatomical room, St.Thomas's IIospital. The following is Mr. Patey's account : — " Partial dislocation of the head of ihe os humerus.— The head of the os humeri on the left side was placed more forzvard than is na tural, and the arm could be drawn no farther from the side than the half way to an hori zontal position.
"`Dissection.—The tendons of those muscles which are connected with the joint were not torn, and the capsular ligament was found attached to the coracoid process of the scapula. When the ligament was opened it was found that the head of the os humeri was situated under the coracoid process, which formed the upper part of the new glenoid cavity; the head of the bone appeared to be thrown on the anterior part of the neck of the scapula, which was hollowed, and formed the lower portion of the glenoid cavity. The natural rounded form of the head of the bone was. much altered, it having become irregularly oviform, with its long axis from above down wards : a small portion of the original glenoid cavity remained, but this was rendered irre gular on its surface by the deposition of cartilage. There were also many particles of cartilaginous matter upon the head of the os humeri, and upon the hollow of the new cavity in the cervix scapulm, which received the head of the bone. At the upper and back part of the joint there was a large piece of the cartilage which hung loosely into the cavity, being connected with the synovial membrane at the upper part only by two or tlzree small nzembranous bands. The long head of the biceps muscle seemed to have been ruptured near to its origin at the upper part of the glenoid cavity, for at this part the tendon was very small, and had the appear ance of being a new formation.' — Signed, James Patey.
" This accident," adds Sir Astley, " hap pens from the same cause which produced the dislocation forward. The anterior part of the ligament is torn, and the head of the bone has an opportunity of escaping forwards to the coracoid process."* The foregoing dissection, which is illus trated by an engraving in Sir A. Cooper's work on Fractures and Dislocations, should not, in our opinion, be considered in any other light than as an excellent specimen of the anatomical appearances to be round in those who have had chronic rheumatic ar thritis of the shoulder joint ; for we consider that these appearances were not the result of an accidental luxation, but the true effects of this slow chronic disease. If Sir A. Cooper
had known any thing of the history of the case during life, we might hesitate to call in question the opinion of so eminent an au thority on such a subject ; but as the only grounds he possessed for forming any opinion were derived from the mere anatomical ap pearances observed in the shoulder joint of the subject in the dissecting-room, we con ceive that every one who studies the report of this dissection, accompanied as it is by an engraving, is at liberty to draw his own con clusion as to what was the real nature of the case ; and to us it seems quite clear that the appearances observed in the examination of the case referred to by Sir A. Cooper were exactly those most frequently found to be the result of chronic rheumatic arthritis as itaffects the shoulder joint. The new form assumed by the head of the humerus, the fact of the cartilage having been removed, and its place supplied by an ivory enamel—the piece of cartilage which hung loosely into the cavity being connected with the synovial membrane, at the upper part only, by two or three small menzbranozts bands — the attachment of the capsular liga ment to the coracoid process—all these cir cumstances related in the above-mentioned case strongly remind us of what we now know to be characteristic marks of the disease we have denominated chronic rheumatic arthritis, as we have so often met with them. Add to this, the observation that the intra-ar ticular portion of the long tendon of the biceps muscle did not exist ; or, as is pre sumed, to have been "ruptured" at its origin.
In all these details we find a very complete account of the anatomy of the shoulder joint which had been the seat of chronic rheumatic arthritis.
On the other hand, such appearances afford no evidence whatever that an accidental luxa tion was the cause of them ; certain it is that appearances exactly resembling those de scribed in Sir A. Cooper's case have been met with in cases in which their cause could not be attributed to accident, because no in jury had been received; while in others it was useless to refer to accident, inasmuch as the morbid action had similarly affected both shoulder joints ; so that by the dissection of such cases we have convinced ourselves that disease, not accident, was the source of the morbid appearances. If the reader will com pare the woodcut (fig.429.), which is designed to represent the anatomical appearances pre sented by the examination of a case (J.Byrne) already detailed, of chronic rheumatic ar thritis of the shoulder, with the engraving of Sir A. Cooper's case of partial luxation of the head of the humerus, he will, we think, agree with us that the writer, in believing that whatever causes influenced the produc tion of the rnorbid appearances in the one were identical with those which produced them in the other. Sir A. Cooper, in our opinion, somewhat gratuitously supposes that his specimen was the much sought-for ex ample of the anatomy of the accident called partial luxation. We say gratuitously, because the previous history of the case he alludes to was unknown, and the accident supposed, to have occurred.