Part 8

Tenth day, a small abscess on the external condyl opened, and a splinter extracted posteriorly.

Fifteenth day, the parts assume a flattering aspect; suppuration favourable; fragments in contact; from this time the dressings are less frequent.

Twentieth day, a bilious diathesis; edges of the wounds livid; loss of appetite; nausea; vomiting; an emetic is administered.

Thirtieth day, unfavourable appearances gone; reunion commencing; wounds visibly healing. Fortieth day, all external injuries healed, except the one situated anteriorly; callus already very firm; gentle motions performed with the limb, which is still surrounded by the apparatus.

Forty-seventh day, the apparatus become useless; motions gradually increased; articulation already tolerably free. Fifty-seventh day, bilious diathesis returned; low diet and evacuants. Sixty-fifth day, the patient discharged from the hospital; consolidation perfect; wounds entirely healed; motions of extension still difficult to be performed in their full extent, but are recovered in a great measure, and will doubtless, in a short time, be completely re-established, provided the same mode of treatment be continued.

MEMOIR VII.

ON THE LUXATION OF THE HUMERUS.

§ I.

GENERAL REMARKS ON THE JOINTS, AND ON THAT OF THE HUMERUS IN PARTICULAR.

1. Nature, who, according to the wants of different species of animals, has varied the number of their articulations, knows also how to vary their structure, according to the uses of the different parts of their bodies. With great mobility, she has sometimes connected great solidity and strength, as is the case in the vertebral column; in other instances, parts very solid and compact, are capable of performing but feeble motions, as the carpus, the tarsus, &c. And, lastly, other parts, again, capable of great motion, possess so little solidity and firmness as to be easily deranged by the action of external bodies. Such, in man, is the articulation of the humerus with the scapula, of the sternum with the clavicle, &c.

2. Hence there exist three classes of articulations, very different from each other. To the last, as enumerated above, belongs, in a particular manner, the history of luxations, and, in this, as the solidity varies, the frequency of dislocations is equally various; no luxation occurs more frequently than that of the humerus; indeed, in a comparative catalogue of accidents of this kind, it alone has, during certain years, occurred oftener, in the Hotel-Dieu, than that of all the other bones, taken collectively.

3. Every thing seems to favour the escape of this bone from its natural cavity. 1st, On the part of the articulating surfaces, a cavity somewhat oval and very shallow, aided by a slight cartilaginous ring, receives a half-spherical head, twice its own diameter from above downwards, and three times as large from before backwards. 2dly, On the part of the ligaments, this articulation is strengthened by only a simple capsule. This capsule is thin and weak on its lower side, a direction in which there is nothing to prevent a luxation, while it is thicker on its upper side, where the acromion and coracoid apophyses, and a strong ligament, present an obstacle almost insurmountable. 3dly, As far as respects the muscles and the motions of the joint, strong and numerous bundles of fibres surrounding the articulating surfaces, communicate to them motions easily performed in every direction, and which, by pushing the head of the humerus against the different parts of the capsule, distend it, predispose it to laceration, and indeed even rupture it, when the quantum of their force is superior to its resistance. 4thly, As far as relates to external bodies, what bone is more exposed to their action than this, particularly among that class of persons, engaged, for a livelihood, in hard labour?

4. Subject to the influence of these different predisposing causes, the humerus would be constantly liable to luxations, did not the scapula, moveable like itself, furnish it, by accompanying its motions, with a point of support, differently disposed, according to the different position of its superior extremity; so that, to this two-fold mobility of the articulating surfaces, is to be attributed, in a great measure, the stability of their connexion.

§ II.

OF THE KINDS OF THIS LUXATION.

5. The upper articulation of the humerus, though predisposed, in general, to luxations, is not equally so in every direction. There is a point at which luxation cannot take place. There are others, where, though possible, this accident has never been observed. It is necessary, therefore, before examining the mechanism of this luxation, to mention with precision, the directions in which it may occur. On this point, writers have differed in a very singular manner. Sometimes, to express the same thing, they have used a different language; and, at other times, have, by the same words, expressed things widely different. Always agreeing as to certain modes of dislocation, they have been divided as to others; while, in the midst of those contrarieties, the surgeon being embarrassed, is at a loss on what ground to found his practice.

6. The ancients, knowing but little of the natural relation of the parts surrounding the joint, were ignorant of the accidental ones, which these several parts assume, in the case now under our consideration. Hence, without doubt, arises the confusion, of their opinions on the subject.

Many admitted of four kinds of luxations; a great number acknowledged only three; some subscribed to but two; while others believed in the possibility of none but one.

7. The first divided differently the directions in which the bone might be luxated. Some contended for luxations upward, downward, forward, and backward; and such was the opinion of the first Greek physicians, predecessors to the father of medicine, who has transmitted the opinion to us accompanied with a demonstration of its fallacy. Others have divided them into those that take place downward, upward, outward, and forward. This division is adopted by Galen, who yet produces only an example of a forward luxation, and does not give us to understand what he means by a luxation upward and inward.

8. The second distinguished the modes of this luxation, sometimes into downward, forward, and backward; as was the case with Oribazes; at other times, into downward, outward, and inward, according to the opinion of Paul of Egina, who, no doubt, adopted exactly the preceding division, expressing it only in different words; sometimes into downward, forward, and upward; such was the sentiment of Albucasis, who, notwithstanding, considered a luxation upward, as a very difficult, and very rare occurrence.

9. The third were of opinion, that, in undergoing a displacement, the head of the humerus could be carried only downward, under the arm-pit, which is the most common direction, or forward, a course which it takes more rarely. Celsus is almost the only writer who has contended for this division. “_Humerus_, says he, _modo in alam excidit, modo in partem priorem_.”

10. Lastly, The fourth believe, with Hippocrates, in none but a displacement downwards, the only one which that physician has met with in his practice. “_At vero humerus, inferiorem in partem excidit; aliam in partem excidere non audivi._”

11. The moderns, in borrowing from the ancients their divisions of luxations, did not, like them, determine a priori and in a vague manner, the precise spot and direction of displacement; but ascertained these points by subsequent observation, with more precision, in proportion as a knowledge of anatomy shed light on them. They also paid particular attention to the essential difference between primitive and consecutive luxations.

12. Petit admitted of four kinds of luxations, 1st, downward, on the edge of the scapula: this is a very rare occurrence: 2dly, outward, under the spine of that bone, a kind very difficult to be primitively produced. 3dly, inwards, under the hollow of the armpit. 4thly, forward, between the corocoid apophysis and the clavicle. With this illustrious practitioner, Heister acknowledged four kinds of displacements; but, here again, was a new variety, both in expression, and in meaning. The one says, downward, under the arm-pit, the other forward, under the pectoralis major; the one, backward, under the scapula, the other outward, under its spine. According to Duverney, luxations are never primitively in any other direction than downward; the others being only the subsequent effect of muscular action.

13. In the midst of these very complicated modes of treating a very simple subject, it is necessary, first, in order to acquire definite ideas, to divide luxations of the humerus into primitive, which are the immediate effect of external violence, and consecutive, which succeed the primitive, through the influence of causes which I am about to consider.

Let us suppose four lines to inscribe, in form of a parallelogram, the oval surface of the glenoid cavity, one representing the superior edge, another the inferior, a third the internal, and the fourth the external.

14. It is evident that the head of the humerus cannot be displaced towards the superior edge. In that direction, must be encountered, the acromion and corocoid apophyses, the strong ligament passing between them, the tendons of the triceps and supra-spinatus muscles, and the fleshy mass of the deltoid; all which, taken together, constitute an insurmountable obstacle to the escape of the head of the bone upwards. Besides, what power could carry it upwards? In order that this kind of luxation might take place, it would be necessary, that the head of the bone should be carried outwards at the same time, as well as upwards, a circumstance which is impossible, because the trunk prevents the lower extremity (the elbow) from being directed sufficiently inward to produce such an effect.

15. On the contrary, in other directions, but very little resistance is to be met with. Towards the inferior edge of the cavity, the long portion of the triceps; the tendon of the subscapularis, towards the internal edge; and towards the external edge, the tendons of the infra-spinatus, and teres minor, yield with ease to a force directed against them, and permit the occurrence of primitive luxations, downward, inward, and outward. Downward, between the tendon of the long portion of the triceps, and that of the subscapularis; inward, between the subscapulary muscle and fossa;[14] and outward, between the fossa infra-spinatus and the muscle of the same name. These modes of displacement are not alike frequent, as will be mentioned presently.

[14] (_La fosse sous-scapulaire_). I know of no English anatomical term for this. I therefore translate it literally. The same is true with respect to “_fossa sous-epineuse_,” translated here, fossa infra-spinata. TRANS.

16. Having escaped from its cavity, and being primitively placed in one of these three situations, the head of the humerus oftentimes changes its position. Then, to a primitive luxation downward or inward, succeeds a consecutive or secondary one; but never to a luxation in an outward direction, if such ever occur, because the spine of the scapula forms an obstacle to it.

A secondary luxation inward, may succeed a primitive one downward; there is nothing to oppose the head of the humerus in the course it takes, to enter between the subscapulary muscle and fossa. If, on the other hand, it be disposed to pass to the external side, the tendon of the triceps opposes it; and, notwithstanding what Petit has advanced, there is no secondary luxation in that direction.

17. It sometimes happens, that, having escaped either from the internal part, or from the inferior part of the capsule, the head passes behind the clavicle, and forms there a secondary luxation upwards, as has been observed by Ambrose Pare, and by Gallien, and of which an example or specimen was preserved in the cabinet of Desault. But, here, the secondary displacement must take place in a slow manner, and when it has taken place, art can seldom remove it, on account of the strong adhesions formed by the bony surfaces. Thus, in the example mentioned, there was a new cavity formed behind the clavicle, and the humerus adhered to the surrounding parts by a kind of new ligaments.

18. It appears from what has been said, that the humerus is subject to four different kinds of displacement. 1st, _Downward_: 2dly, _outward_, in both of which directions the luxation is always primitive; 3dly, _inwards_, where it is sometimes primitive, and sometimes consecutive; 4thly, _upwards_, where it can never be otherwise than consecutive.

The second and fourth are very rare occurrences, and bear so small a proportion to the others, that the latter alone ought to command the attention of the practitioner.

§ III.

OF THE CAUSES AND THE MECHANISM.

19. The causes and the mechanism of luxations of the humerus, vary according as the displacement is primitive or consecutive.

The action of external bodies, directed against the arm, but more particularly falls, where this part strikes forcibly against a resisting body, give rise in general to primitive luxations, and, according as it is differently situated at the time of the fall, the humerus determines, by its position, the different kinds.

20. If it be separated from the trunk, without being carried either before or behind it, if the elbow be elevated, and the fall be on the side, the weight of the body, being almost entirely supported by this bone, pushes its upper extremity downward, distends the inferior part of the capsule, lacerates it, and produces a luxation downward, in which it may even be favoured by the action of the pectoralis major, the latissimus dorsi, and the teres major, as has been judiciously observed by Fabre. In such a case, these muscles, involuntarily contracting to support the trunk, act like the power or force in a lever of the second kind, the resistance to which is formed by the head of the bone, which they draw downward, while the lower extremity of the humerus, resting on the ground, constitutes the fulcrum. Some authors even regard, as an immediate cause of luxation, the powerful contraction of the deltoid muscle, which depresses the head of the bone, and forces it through the lower side of the capsule, a mode of displacement, the existence of which observation incontestibly establishes. The case of a scrivener, so often cited, is well known, who in lifting a book of records luxated his humerus in a downward direction.

21. The mechanism of a primitive luxation inwards, differs a little from the preceding. The elbow, being at once separated from the trunk, and carried backward, the person falls: the weight of the body rests on the humerus; the capsule is lacerated in its fore-part; and a displacement in the same direction supervenes.

22. In a luxation outwards, the elbow is carried forward, towards the opposite shoulder; the capsule being stretched outwardly, gives way in that part, provided the humerus be acted on by a sufficient power. But what can this power be? In a fall, the arm being pushed against the trunk, and stopped by it, cannot carry its motion to a sufficient extent to produce a laceration of the capsule. Hence a luxation outwards must be extremely rare. Indeed no instance of it is to be found in books of surgery. Desault, in particular, never witnessed it. Besides, when in a fall, the arm, separated from the body, is carried backward or forward, the weight of the body acts obliquely on it, and it is but partially subjected to the action of the latissimus dorsi, the pectoralis major, and the teres major. So that no kind of luxation ought from these considerations, to be very frequent, except that in a downward direction, where the influence of both causes is direct. Yet luxation inwards is common enough, and in many instances Desault has observed this primitive mode of displacement, though many modern authors doubt the fact, believing, with Hippocrates, that, primitively, all luxations are downwards.

23. It may so happen that in a primitive luxation, the capsule is only greatly stretched, in which case, the articulating surfaces are but partially displaced; but this membrane more frequently suffers a rupture, through which the head of the bone escapes. To this phenomenon writers, in general, have paid too little attention, notwithstanding the opening of dead bodies has oftentimes demonstrated its existence to practitioners, particularly to Desault, who has given two examples of it modelled in wax; one, of a luxation inward, and the other downward, both found in subjects that died in the Hotel-Dieu. Bell relates some analogous facts, and another English surgeon has also had occasion to meet with them.

24. Oftentimes, in compound fractures, one of the fragments passes through the integuments. In the dislocation of the humerus something similar to this occurs. The capsule is sufficiently lacerated to allow the head to escape; but the opening, being then too narrow, forms around the neck of the bone a noose or kind of collar, which prevents it from re-entering the place which it originally occupied. Thus, in the fractures of which I have just spoken, the aperture in the skin does not, at times, admit of the reduction of the fragment, without a previous dilatation.

In this case, an attempt is made to reduce the luxation: the capsule is pressed in folds against the glenoid cavity, and, interposing itself between it and the head of the humerus, renders fruitless the efforts of the surgeon who would replace the bone. Desault was the first who observed this practical fact, two instances of which are recorded in his journal, and which has frequently since occurred in the Hotel-Dieu. In such a case, the head is in general extremely moveable, because, being entirely without the capsule, there is nothing to impede its motion.

25. When, to a primitive luxation a consecutive one succeeds, several causes may concur in its production. If a second fall happen, the arm, being separated from the body, the head of the humerus having nothing to retain and secure it, obeys, with great facility, the power tending to displace it in that direction, and suffers a fresh removal from the bed which it accidentally occupies.

CASE I. A man fell in descending a ladder, and luxated his humerus in a downward direction. Desault being immediately called, discovered the nature of the disease, but deferred the reduction till evening. In the interval, the patient went to get into a chaise: his foot slipped, and he fell a second time. The pains became more severe than at the time of the first accident; and Desault, on his return, instead of finding, as in the morning, the head of the humerus under the hollow of the arm-pit, discovered it to be behind the pectoralis major.

26. Muscular action is one permanent cause of a new displacement. Suppose the humerus luxated downward, the pectoralis major, and the deltoid muscles draw its superior extremity upward and inward, which, offering to their action but a feeble resistance, changes its position and that in a two-fold direction.

27. The different motions of the arm may also, according to their direction, produce the same effect. Thus we have often witnessed a luxation inwards succeeding to a luxation downwards, in consequence of unskilful attempts to reduce it.

§ IV.

OF THE SIGNS.

28. The diagnosis of luxations of the humerus, presents in general, but few difficulties.

Whatever may be the mode or seat of the displacement, there always exists, as Hippocrates has observed, a manifest depression under the acromion, which exhibits a prominence more perceptible than in its natural state. The motions of the part are almost all accompanied with pain; the greater part of them are impracticable; all of them very much confined. The arm cannot move, without a synchronous motion of the shoulder, because, the articulation being no longer able to exercise its functions, these two parts constitute, so to speak, but one body.

29. Besides these signs, which characterize generally every species of luxation of the humerus, each species is marked by certain others peculiar to itself. If the displacement be downward, the arm is a little longer than in its natural state; it can be moved gently outwards; but an acute pain is the inevitable consequence of moving it forward or backward. The elbow is more or less removed from the axis of the body, by the action of the deltoid, the long portion of the biceps, and the supra-spinatus muscles, which, being unnaturally stretched, contract themselves and tend to carry the bone outward. The pains which result from this position, force the patient, in order to relieve them, to lean towards the affected side, to keep the fore-arm half-bent, the elbow resting on the hip, so that the arm, finding a place of support, may be freed from the painful movements, and from the disagreeable sensation produced by its own weight. From this attitude alone, was Desault in the habit of discovering luxations in a downward direction, and was rarely mistaken in his diagnosis. It is thus, that, in a fracture of the clavicle, the inclined position of the patient is oftentimes, at first sight, characteristic of the nature of his complaint. Beneath the hollow of the arm-pit there always exists a protuberance more or less perceptible, formed by the head of the humerus.

30. To the general signs of luxations of the humerus (28), that in an inward direction adds the following: the elbow, being separated from the trunk of the body, is carried a little backward; the humerus seems to direct itself towards the middle of the clavicle; motions backward are not very painful, while those in a forward direction are extremely so; under the pectoralis major a manifest protuberance exists; the arm is but little longer than in a natural state; the attitude is the same as in the preceding case.

31. Should a luxation in an outward direction occur, it would be particularly characterized by a hard tumour under the spine of the scapula, by the direction of the elbow forward, by its separation from the trunk, and by a little increase in the length of the arm.

A protuberance behind the clavicle, an obvious shortening of the arm, together with its direction, would plainly disclose a luxation upwards.

32. The signs discriminative of the nature of luxations of the humerus, are not always accompanied by the same degree of certainty as those that announce merely its existence. Thus, nothing is more difficult than to determine when a luxation inward is primitive, and when it is consecutive, the same phenomena being common to both. Nothing but an exact history of the disease, stating the order in which the phenomena have succeeded each other, can throw light on this point, which is the more interesting and important, as, according to the one or the other state of things, the processes of reduction ought to vary. In the first case, the head re-enters its natural cavity by a short route; whereas, in the second, it arrives there by a much longer one.

If, as Petit pretended, there exist luxations backward, sometimes primitive, and sometimes consecutive, the same remark may be applied to them with equal propriety.