Part 5

OF DISPLACEMENT.

11. Most of the symptoms formerly mentioned (5 and 6) as accompanying a fracture of the clavicle, are evidently the result of a displacement of its broken ends. Yet this phenomenon, taken notice of by all authors, and considered by them as a necessary effect of the disease, does not occur in every case (8). There are instances, in cases of transverse fractures, where the extremity attached to the shoulder, has retained its natural position. Three examples of this kind occurred in the Hotel-Dieu in the course of the year 1787.

12. Instances have also been known, in which the sternal fragment, when fractured obliquely upwards, has supported the end of the humeral in such a manner as to prevent any derangement. Desault was accustomed to relate several cases, where similar occurrences took place; but, in general, this state of things is rare, in comparison with that in which the fragments lose their natural level.

Almost always, then, there is more or less of a perceptible overlapping (chevauchement) produced, either, by the elevation (a circumstance which is very rare) of the external fragment over the internal; or, (as commonly occurs) by the depression of the former beneath the latter.

13. Of the first of these modes of displacement (a mode but rarely mentioned by authors) a few examples are to be found among the observations of Desault, one of which he has recorded in his journal. Hippocrates speaks of the phenomenon as a thing that was familiar to him.

14. The second kind of displacement, that which we constantly find in practice, and which the laws of muscular action render almost inevitable, takes place in such a manner that the shoulder appears to obey the impulse of two powers, one of which draws it downwards, and along with it the external fragment of the clavicle, which is displaced by this power in the direction of its transverse diameter, or thickness. The other power approximates the shoulder to the breast, and draws it forward, carrying along with it the same fragment, which is by this means displaced in a longitudinal direction.

That we may the better understand them and their effects, let us, in our minds, separate these two powers, although they are perfectly simultaneous in their action. A knowledge of them will lead us to a knowledge of the resistances which ought to be opposed to them. But let us first remark, that the humeral fragment, being drawn downward and inward, takes sometimes such a direction, that its internal extremity passes backward under the sternal fragment, its external end continuing to point forward: this disposition can be understood from its natural direction.

15. The first of these powers, namely, that which depresses the point of the shoulder, appears to have escaped the notice of the ancient physicians of Greece, who attributed the apparent depression of this part, to the elevation of the sternal fragment, and, accordingly, endeavoured by making compression on the latter, to restore it to a level with the other. Hippocrates, more judicious than those who had preceded him, demonstrated that their doctrine, false in its principles, was still more dangerous in its consequences, and that the sternal fragment being immoveable, lost its relative position with respect to the humeral, only because the latter was depressed by the weight of the arm. This doctrine of the father of physic is satisfactorily proved, by a comparison of the sound shoulder with the diseased one, and has since been admitted by all practitioners. Indeed, the mere recollection that one of the uses of the clavicle is to support the shoulder at that level necessary for the performance of its functions, is alone sufficient to convince us, that, in case of its ceasing to fulfil that office, the shoulder must obey the laws of its own gravity, increased by that of the hand and arm.

16. The illustrious Petit, and with him Duverney, in acknowledging this cause of displacement, have added to it as another the action of the deltoid muscle on the external end of the bone; in this action, the end of the clavicle is the moveable point, while the humerus affords the fixed point. But how can we admit this cause, when the humeral fragment, in passing under the sternal, moves in a backward direction? So far is the deltoid muscle from drawing the bone downward, that here the bone rather draws the muscle in part backward, and yet, in such a case, the displacement is as perceptible as in any other. Besides, when the sternal fragment, broken obliquely upwards, supports the humeral and prevents a displacement, why does not the deltoid produce this displacement?

It is then in the weight of the arm and shoulder alone, that we must look for the passive power, which depresses them, and which produces a displacement in the direction of the transverse diameter or thickness of the clavicle.

17. A second power, highly active, co-operates with this. I allude to the permanent contraction of the muscles, that extend from the breast to the clavicle and shoulder: from this cause arises the displacement in the longitudinal direction of the bone.

The pectoralis major, the pectoralis minor, the subclavius, the serratus major, and the trapezius, unite their efforts in producing this displacement. These muscles are, in certain respects, antagonists to each other, but they all unite in drawing the shoulder forward and inward. None of them appears to act with more effect than the pectoralis major. To this, in particular, is to be attributed the displacement in a forward direction.

Except in the instances stated above, the action of the muscles is not immediate. They act only secondarily on the external fragment, which, being stedfastly attached to the scapula and humerus, is obedient to the motions impressed by the muscles on these two bones; motions which, in a sound state, the clavicle has a power of controlling.

18. To the weight of the lower extremity (15 and 16), and the spontaneous action of the muscles (17) must be added, as another cause of displacement, the motions which are communicated to the arm by external bodies, and which, being imparted ultimately to the clavicle, derange the fragments, by separating them, approximating them, or making them overlap each other, according to the direction in which they act.

19. When a fracture occurs at the extremity next the shoulder, no displacement of the fragments in general takes place. This circumstance is attributed to the action of the trapezius, which draws each fragment upwards with equal force. However this may be, it is doubtless to such cases that we must refer the complete cures, obtained without any retentive apparatus, by Gasparetti, Brown, and other writers. Hence also, without doubt, arise the difficulties experienced by certain practitioners, such as Duverney, with respect to the diagnosis of this disease. These fractures may be mistaken for fractures of the acromion, being situated so immediately in its vicinity.

§ VI.

OF THE REDUCTION.

20. On looking into the causes of that displacement (15 ... 18), so common in fractures of the clavicle, it appears that in almost every case, the external extremity of the humeral fragment is drawn, by a double power, downward, inward, and forward. Hence it follows, 1st. That the resistance opposed to this power, by the means used for the purpose of reduction, and the retentive apparatus subsequently employed, ought to be directed upward, backward, and outward, these directions being the reverse of those in which the powers of displacement act: 2dly. That, in as much as these powers, viz. the weight of the parts and the action of the muscles, are in constant operation, and, besides, as the motions of the arm are continually disturbing the fragments of the bone, the apparatus ought to be equally constant in its action, and should keep up, without any remission, the effect produced, at first, by the means of reduction. This principle is applicable to every case, and ought to be the standard of comparison, for determining the advantages or disadvantages of different bandages, and processes for the reduction of fractures of the clavicle.

21. But we are not to suppose, that these processes have heretofore manifested an exact application of this rule. Hippocrates directed to press the arm close to the ribs, and at the same time to push it upwards, in such a manner, as to make the shoulder appear as sharp and pointed as possible. Hence his precept, to lay the patient down on his back, the back being supported by some projecting body, and then to press the shoulders backward; hence again, when the humeral fragment is drawn inward, his advice to press the elbow close to the breast. This twofold expedient was attended with great difficulties, even under the direction of the father of medicine. Celsus only copied Hippocrates, adding nothing whatever to his mode of practice. Paul of Egina, more judicious in this case, conceived, that for the purpose of forcing the shoulder outward, and rendering it, agreeably to the idea of Hippocrates, very projecting and sharp, it would be advisable to place the fulcrum or point of support, not in the middle of the back, but under the arm-pit. A woollen ball was employed by him for this purpose, a practice which would, at once, have carried the art near to perfection, if, after being employed to reduce the fragments, this process had been continued for the purpose of retaining them in apposition.

22. No new method distinguished the surgery of the Arabians. It is necessary to come down to the time of Guy of Chauliac, before we meet with the method which is almost universally adopted at present, and which consists in placing between the shoulders, the knee of an assistant, whose hands are to be employed in drawing them forcibly backwards. But it is evident that this is only doing, while the patient is in an erect position, what Hippocrates did, after having laid him with his back on a projecting body. Here, then, the art seems to have degenerated, after the time of Paul of Egina: and, indeed, on comparing this process with the general principles already established (20), it will be immediately perceived, that the powers of replacement do not here act in an opposite direction to those of displacement.

Hence the difficulties of reduction, the time spent in the operation, and the sufferings by which it was sure to be accompanied. The fragments were brought together, it is true; but it was only by varying the movements, and changing their direction, that the point of contact was ultimately found.

23. Desault conceived, in the year 1768, that to reduce, in the most effectual manner, a fracture of the clavicle, it was necessary not only to push the shoulder backward and upward, as was commonly done, but, above all, to force it outward, and that the power destined to draw it in this latter direction, ought to act horizontally, according to the course of the clavicle, in the same way, as, in an oblique fracture of the thigh or leg, the extension for replacing the fragments is made in the direction of the bone.

24. As the union of the humerus to the clavicle, by means of the scapula, communicates to the one the movements of the other, it is easy, by placing the ball used by Paul of Egina, under the arm-pit, to convert the arm into a lever of the first kind.

That form of lever, where the weight to be raised or the resistance to be overcome, is at one end, the force at the other, and the fulcrum or prop between them. This form is well represented by the handle of a pump, where the piston is the weight or resistance, the hand of the drawer of water the force, and the iron pin, on which the handle works, the fulcrum or prop.

TRANS.

The lower extremity of the arm being then pressed towards the body, the upper end is separated from it, and becomes, with regard to the clavicle, what the efforts of an assistant who makes the extension, in a fracture of the leg, are to the foot of the patient.

The mode of reduction being established, it was necessary, in the next place, to invent a bandage, calculated to retain the broken ends of the bone in contact. Desault thought it practicable to unite these two points of treatment, in the same process, that is to say, to reduce, and at the same time to retain the fracture. Here the art is indebted to him for an improvement, which, I will venture to say, carries it near to perfection. To judge of this, it will be necessary only to take a hasty survey of the different kinds of apparatus proposed by different writers.

§ VII.