In the case the writer has adduced (J. Byrne, (fig. 429.), the history was known, and has been preserved, with the account of the post-mortem appearances which the examination of the shoulder joint presented.
At the meeting of the British Association at Bristol in September, 1836, the author gave an account of this chronic rhemnatic disease, as it engages most of the joints. When speaking of its effects on the shoul der, he alluded to this case published by Sir A. Cooper ; and then demonstrated, as he thought, to the satisfaction of the meeting, that the specimen (fi'g. 429.) of this chronic rheu matic disease which he then laid before them for inspection, corresponded exactly to the ap pearances found in the supposed case of " par tial luxation of the humerus " delineated in Sir A. Cooper's work. The opinion which he at that trme expressed (now twelve years ago) has since been amply confirmed by his subsequent experience*, and by the opportu nities he has had of further investigating the nature of this disease.
In the Museum Anatomicunzt of Sandi fort, 1827, we find delineated the bones of the shoulder joint which present all the cha racters of the chronic rheumatic arthritis, with partial displacement upwards of the head of the humerus. Sandifort also, we feel sure, has fallen into the error of concluding with out proof, that this specimen of the bones of the shoulder constituted an example of par tial luxation from accident (" luxatio ossis humeri ab externa"). The subject of this case, he says, was a robust man: the head of the humerus having been driven upwards between the coracoirl process and the acromion, a new articular surface was produced, partly on the upper narrow part of the glenoid cavity, and partly on the root of the coracoid process. This new articular surface, in its centre porous, was as to its circumference hard, polished, and ivory-like (" partim porosa sed cmtera valde polita ac quasi eburnea"), and had been in habitual contact with the head of the humerus. The latter was much enlarged, and its circumference near the corona of the head was much increased by the addition of a hard rounded margin (" margine revoluto calloso"). The wearing away of the upper part of the great tuberosity, the eburnisa tion of the summit of the humerus where it came in contact with the concavity of the coraco-acromial vault, the preternatural con tact of the head of the humerus with the under surface of the acromial extremity of the clavicle, are also noticed. " Caput ossis humeri amplitudine auctum, margine revoluto calloso, in superficie articulari affert eandem prmternaturalem glabritiem et duritiem, dum in vertici, ubi tuberculum majus occurrit, superficiem exhibet partim glaberrimarn, par tim inequabilem, rugosam, qum juxta sum mum humerum movebatur trituratione, etiam locum habuisse inter marginem inferiorem claviculm, et verticem capitis humeri mani feste apparet ; subluxatio in superiora ergo hic locum habuit."*
Here we find the description of the bones unaccompanied with any account of anatomi cal characters of the other structures of the joints ; nor is there any proof adduced that any accident had occurred to produce the appearance noticed ; we may therefore, we think, conclude, that the history of the case was unknown. When we compare Sandifort's description of the above case, accompanied as it is with an engraving, with the account given by us in the preceding pages of the dissection of other cases of the chronic rheumatic ar thritis as it affects the structures of the shoulder joint, we think we may safely con clude tbat this case, adduced by Sandifort as an example of partial luxation of the head of the humerus upwards from external injury, must be considered as presenting in the bones described the anatomical characters of chro nic rheumatic disease, as it very commonly affects the bone of the shoulder joint.
In the anatomical examination of advanced cases of this disease of the shoulder joint, which we have witnessed, in which there had been partial luxation of the head of the humerus upwards — when the deltoid mus cle has been cut through, the head of the humerus has been usually found exposed, and in absolute contact with the under surface of this muscle, having passed through the upper part of the capsular ligament. In such cases, the head of the humerus has been found to present the usual characteristic appearances of this chronic rheumatic disease ; that is to say, the cartilage has been absorbed, and its place supplied by an ivory-like enamel. The arti cular portion of the tendon of the biceps has also been removed, as well as all those parts which in the normal state intervene between the summit of the head of the humerus and the under surface of the coraco-acromial arch. The superior portion of the capsular ligament itself has been found perforated ; and the under surface of the coraco-acromial vault excavated, and has become a new and sup plementary socket for the head of the hu merus (fig. 429.).