Besides lesions affecting the bones, mus cles, and tendons, injuries of other tissues may be found occasionally to accompany or succeed to dislocations of the shoulder.
A dislocation of the head of the humerus may be accompanied with an cedematous swelling of the arm and forearm ; with a pa ralysis of the dislocated extremity, or with a laceration of the axillary artery, and a dif fused aneurism ; it is said also that occasion ally an emphysematous swelling of the shoul der has followed the reduction of the dis location ; and on other occasions, that the articular structures have been attacked with very severe infianzmation. For example, as to this last : Mr. Hunter gives an account of a case of dislocation of the shoulder-joint, which he dissected three weeks after its re duction, from which, if we could be influenced by one case, we might infer that inflammation, though latent, may sometirnes be the conse quence of a dislocation of the head of the humerus. Mr. Hunter's observation is as follows : " What was very remarkable, and what I tlid not expect, there was a good deal of pus in the joint." * Partial or general paralysis of the muscles of the arm has also been observed as a con sequence of a dislocation of the head of the humerus, particularly when either the circum flex nerve alone, which is that most usually injured, or all the nerves of the brachial plexus have been violently contused, or greatly stretched ; or even torn across either at the time of the accident, or by the violence of the means used to restore the luxated humerus, when the dislocation has been left long un reduced. Flaubert, of Rouen, speaks of an enzphysenza of the chest succeeding his efforts to reduce an old luxation of the humerus ; and it is known that Desault had already ob served a similar occurrence. A Memoir, con taining six cases published in the Repertoire d'Anatomie et de Chirurgie, by M. Flaubert, ,surgeon in chief to the Hotel Dieu de Rouen, is not well calculated to encourage practitioners to attempt the reduction of old dislocations. In five of these cases the reduction was fol lowed by serious accidents. M. Flaubert observes, that in many cases when para lysis of the upper extremity had been attri buted to the dislocation itself, he believes it was rather owing to the violent efforts made for its reduction ; laceration of muscles and extensive abrasion of the skin have been no ticed as the consequence of these efforts, and even death from diffuse inflammation has oc curred ; but these accidents, whether the re sult of dislocation, or of the means used to restore the bone to its place, must be consi dered as rare in this country, as from the comments of Mr. Mar, and the observations of the Editors of the Lecons Orales of Du puytren, they seem to have been in Paris. The latter observes, " Le hasard qui a fourni A M. Flaubert, dans le court espace de trois ou quatre ans, un ensemble de tous les acci dens les plus graves qui puissent determiner la reduction, est vraiment extraordinaire : faut sans doute en chercher la cause dans des eirconstances particulieres, qui sont incon nues."*
Alterations of the nerves. —We have noticed as belonging to the symptoms of dislocation of the head of the humerus, that the patient complains of pain extending down the course of the nerves of the arm and the forearm, ,and also of numbness. These symptoms generally disappear when the dislocation is reduced, but sometimes they persist. The pressure which the nerves of the axillary plexus undergo has naturally been referred to as the cause of these unpleasant symptoms. The nerves, besides being stretched, have been sometimes even torn across; when this has oc cured the effects produced must long remain ; such cases are very rare. Among all the nerves in the vicinity of the shoulder-joint which have been referred to as the seat of injury the result of luxation of the humerus, the eircunz flex nerve, which supplies the deltoid, is that which has been found most frequently injured. Jndeed, from the manner it winds round the neck of the humerus to arrive at its destina tion at the under surface of the deltoid mus cle, it can scarcely escape being stretched and elongated, and such a lesion of this nerve we may well expect to be followed by a pa ralysed condition of the deltoid muscle. The circumflex nerve has been found compressed by the dislocated head of the humerus, flat tened, and firmly adherent to the capsule of the joint. We find in the Museum of Bartho lomew's Hospital, (Catalogue, p. 124, vol. i., 42.,) a preparation ot' a shoulder-joint, exhibiting a dislocation of the humerus, which occurred eighteen months before death. " The head of the humerus rests on the anterior surface, near the inferior border of the sca pula. The tendons of all the capsular mus cles were entire ; the long tendon of the biceps retains its attachment to the glenoid cavity. The circumflex nerve is compressed by the head of the dislocated bone, and was in con sequence flattened, and firmly adherent to the capsule of the joint. The dislocation had been followed by permanent paralysis of the del toid muscle." . Artery.— Luxations of the head of the hu merus have been found complicated with alesion of the axillary artery. This we believe to be a very rare occurrence. M. Flaubert of Rouen cites cases of this lesion to have occurred in the Hotel-Dieu de Rouen, as a consequence of the efforts made by surgery to reduce old luxations of the humerus. In the following case, which the writer thinks of sufficient im portance to be here introduced, the laceration of the axillary artery was recognised a few minutes after the dislocation had occurred — and before any effort whatever had been made to restore the humerus to its place.