" When the articulation was first opened, the long tendon of the biceps could not be seen, but on more particular examination it was found to have been ruptured, the portion con nected with the muscle being intimately at tached to the bicipital groove of the humerus, while the portion belonging to the glenoid cavity WaS much diminished in size, and pre sented a mere rudiment." We have already made the remark, that when the shoulder joint is the seat of chro nic rheumatic arthritis, the neighbouring acrornio-clavicular articulation is frequCntly affected with this same disease. Now, in care fully examining Professor Hargrave's specimen, we shall find that not only do the anatomical characters which belong to chronic rheumatic arthritis exist in this shoulder joint, but also that the acroinio-clavicular articulation in the same specimen is enlarged externally ; and that, on examining it internally, it presents undoubted traces of this chronic rheumatic disease. Upon the whole, therefore, we feel convinced that this specimen produced by Professor IIargrave a3 an example of a case of partial luxation inwards, the result of acci dent, does not really afford any proof that exter nal injury was the cause of the partial lux ation.
In thus differing from Professor Hargrave, we would make the same remarks which we have already made in allusi,n to Sir A. Coo per's case, at page 591. of this article. The pro gress of science will soon settle the question.
Partial displacement of the head of the hu merus downwards has been observed to be the result of chronic rheumatic disease of long standing ; but after much diligent inquiry in museums and in books, I can find but two well-marked specimens of this morbid change. The most remarkable of these specimens is a left scapulo-humeral articulation, which is contained in the museum of the College of Surgeons, Dublin. The history of the case is unknown : the preparation formed part of the collection presented by Dr. Kirby to the College of Surgeons in Dublin. The head of the left humerus in this specimen is greatly enlarged, and a proportionate glenoid cavity has been formed to receive it. The head of this bone had descended so much beneath its ordinary situation, that a new gletioid cavity had been formed to receive it on the axillary border of the scapula. The lower part of the old glenoid cavity was still partially occupied by the enlarged head of the humerus, but the new addition to the cavity extends down wards for the space of an inch and half below its ordinary situation. The new glenoid cavity is enamelled on its surface, and en larged on its posterior margin by several irregular-shaped bones of new formation. The capsular ligament in this case has been partly ossified.* If we look over the engravings in Sandi fort's Museum Anatomieum, we shall find, W e think, a specimen of partial displace ment of the head of the hunzerus downwards, the result of this chronic rheumatic dis ease. The writer of the catalogue considers the specimen to have been the result of acci dent, and has appended a history to the case, giving an account of somewhat equivocal symptoms. Whether these symptorns,—such as extensive effusion into the cavity of the joint, of crepitus having been felt on the mo tions of the hones on each other,—were the re sult of accident or of disease, their origin is re ferred to accident. When we carefully. compare
the engraving with vvhat we have seen of other specimens of this disease elsewhere, we must, we think, come to the conclusion, that this example adduced by Sandifort must be shkred as the result of chronic rheumatic arthritis of long standing, with partial displace ment of the altered head of the hunzerus down wards (fig. 431.). Upon looking at the wood cut we notice the acromio-clavicular ar ticulation enlarged as if from chronic rheu matic disease. The acromion process is divided into two portions ; a phenomenon we have so frequently noticed to accompany this disease of' the shoulder joint (see p. 587.). We also notice the additional portions of bone of new formation attached to the capsular ligament so common in this disease, and the addition of an osseous margin to the glenoid cavity ; all tbese circumstances, so well seen in the origi nal drawing to be found in Sandifort's weal( as large as nature, we have attempted, in a re duced form, to repeat here.
Finally, the head of the humerus may be not only displaced partially upwards as the result of this chronic rheumatic disease, par tially inwards, and, as we have just proved, also partially downwards, but the most re markable abnormal appearances the writer has witnessed from this chronic disease, has been in two specimens contained in the Museum of St. Bartholomew's Hospital, in which it will be found that the head of the humerus, which had been affected by this chronic disease, was thrown completely backwards on the dorsum of the scapula. In this case the displacement was double, and two new glenoid cavities had been formed for the reception of the enlarged heads of the humeri behind the glenoid cavi ties, and partly beneath the bases of the spines of the scapulce just where the head of the humerus has been found to rest in the ordi nary dislocation backwards from accident ; but in this case, although the history was unknown, that these appearances were not the result of accident is almost certain, as similar abnormal appearances are ob servable on each side. The notice of this preparation in the catalogue of the museum is as follows (p. 108-32.) :— " The bones of both the shoulder joints of an adult. In each joint there has been ulceration,' or such absorption as occurs in chronic rheumatism of the articular surface of the head of the humerus, and the glenoid cavity. The heads of the humeri are flattened and enlarged by growths of bone around their borders; and the glenoid cavities, enlarged in a corresponding degree, and deepened, extend backwards and inwards to the bases of the spines of the scapulm. The articular surfaces, thus en larged, are mutually adapted, and are har dened, perforated, and in some parts polished and ivory-like. The changes of structure are symmetrical, except in that the articular surfaces of the right shoulder joint are more extensively polished than those of the left."