fall from a height of forty-eight feet, and in 1, Krönlein, the result is unknown. Of the 3 recoveries, the joint suppurated in 2, Prior, Richet's 2d, the process ending in ankylosis in one of them; in the remaining 1 the patient recovered apparently without suppuration, the fracture of the olecranon united by a fibrous band one centimetre long, and two and a half months after the accident the hand could be brought to the mouth and the elbow extended to an angle of 150°. Whether antiseptic methods will improve this poor record remains to be seen.

Treatment. In all the cases in which the olecranon rests against the lower part of the end of the humerus, the so-called imcomplete dislocacations, reduction has been easily effected by pressing or pulling the upper end of the forearm downward and backward, or by flexing the limb against the knee or the arm of an assistant placed in the fold of the elbow. In Greenaway's case the bones slipped into place almost spontaneously when the elbow was flexed.

In the cases in which the bones are displaced further upward it is desirable to flex the limb within a right angle and then to pull the upper ends of the bones back into place by a strap passed around the front of the forearm close to the elbow.

Dislocations complicated by compound fracture of the olecranon must be treated in accordance with the general principles of treatment of compound articular fractures, of which they are a severe form, severe because of the greater extent of the laceration of the soft parts.

DIVERGENT DISLOCATIONS OF THE RADIUS AND ULNA.

The characteristic feature of this form is that the radius and ulna do not accompany each other, but are displaced in divergent directions. Two varieties have been observed: the antero-posterior, in which the ulna passes up behind the humerus, and the radius passes up in front, and of which there are 11 recorded cases; and the transverse, of which there is only a single case, in which the divergence was mainly lateral, the olecranon passing to the inner side behind the epitrochlea, and the radius to the outer side. Several authors make an additional variety, ulna backward, radius outward, on the basis of the case of Samuel White quoted by Cooper (Disloc. and Fracts. Am. Ed. page 384) which seems to me to be a dislocation of both bones backward and outward; and Poinsot makes a fourth variety of the case of Mons which I have placed among dislocations of both bones forward.

1 Bulley, Provincial Med. and Surg. Journal, 1841, quoted in the Gazette Médicale, 1841, p. 666; Michaux, quoted by Debruyn in Annales de Chir. Française et Etrangère, 1843, vol. 9, p. 52; Mayer, Gazette des Hôpitaux, 1848, p. 232; Von Pitha, Pitha and Billroth's Chirurgie, 4th vol. 2d Abt. B. p. 78; Chevalier, Arch. Méd. Belges, Oct. 1870, quoted by Bardeleben, Chirurgie, vol. 2, p. 759; Gripat, Bull. de la Société Anatomique, 1872, p. 176; Arnozan, Bordeaux Méd. 1873, p. 402, quoted by Poinsot, loc. cit., p. 945; Tillaux, Gazette des Hôpitaux, 1877; p. 786; Minich, Lo Sperimentale, 1880, quoted by Poinsot; Mason, N. Y. Medical Record, 1880, vol. 17, p. 397; Scott, Bristol Med. Chir. Journal, March, 1886, p. 36. 2 Guersant, reported by Warmont in Revue Médico-Chirurgicale. vol. 16, p. 303, quoted by Pingaud in Dict. Encyclopédique, art. Coude, p. 600, and by Poinsot.

A. Antero-posterior.-Excluding Chevalier's case, of which I have no details, the ten patients were, with one exception, Tillaux, males, and with two exceptions, adults; one was nine years old, Arnozan; another thirteen, Gripat. The cause was usually a fall from a considerable height, or with violence, as from a moving railway car, a horse, or a wagon; in one it was a fall while carrying a heavy timber, in another while wrestling; and in Tillaux's the patient, while lighting a match, struck her elbow against a piece of furniture behind her; the pain was so great that she fainted and fell to the floor, where she was found with her elbow abducted and flexed. Scott's patient was thrown from a horse, striking upon his head and hands; he found his elbow dislocated and the forearm partly flexed; a bystander pulled it straight, and he felt something give way in the joint, and a bone appeared to slip forward; possibly a dislocation of the ulna alone backward was thereby transformed into the divergent one which was afterward recognized. Von Pitha's patient fell head foremost from the second story of a building upon a pile of planks between which the extended forearm was caught and held while the body was violently precipitated backward.

Pingaud (loc. cit., p. 598), experimenting upon the cadaver, found it easy to produce the dislocation by forced pronation of the forearm after division of the internal lateral ligament; this fact, taken in connection with the fall upon the hand noted in several of the cases, indicates that the mechanism, in these cases at least, is a lateral outward flexion, by which the internal lateral ligament is ruptured, followed or accompanied by forcible pronation, and then by the direct movement downward of the humerus between the two bones. Fracture of the epitrochlea observed in one case, Arnozan, supports the theory of outward lateral flexion. In two cases, von Pitha, Gripat, the coronoid process was broken; in both the fall was from a considerable height.

The explanation of the mechanism in the two cases in which the injury was attributed to a fall upon the abducted and flexed elbow, Michaux and Tillaux, shares in the difficulty which attaches to the explanation of dislocation of both bones backward by the same cause. If the alleged rotation of the ulna backward and outward around the radius, by which the internal lateral ligament is torn, is accepted, it will not be difficult to conceive that the radius may remain in front; but even this leaves unexplained the forcible descent of the humerus between the two bones which requires the rupture of the annular and interosseous ligaments.

Pathology-Two of the patients, von Pitha, Gripat, died of the associated injuries, but the displacement at the elbow was much greater than that observed in the other cases.

In von Pitha's the limb was shortened about three inches, and very much enlarged at the elbow. The olecranon and radius were easily recognized behind and in front of the humerus respectively, and were reduced by slight traction, but the reduction had no permanence. The skin was unbroken. The autopsy showed a wide separation of the radius and ulna from each other, complete rupture of the capsule, and of the annular, interosseous, and both lateral ligaments, fracture of the coronoid process, and avulsion of the biceps and brachialis anticus.

In Gripat's case, a boy thirteen years old, the coronoid process had been broken off and the olecranon had passed almost directly upward, remaining close to the posterior surface of the humerus; the radius was displaced forward and outward. The internal lateral ligament had been torn away at both its insertions; the external one remained attached at its upper insertion, and to the broken coronoid process, and part of the anterior ligament. The annular ligament was torn away at its posterior attachment to the ulna.

Symptoms.-The attitude of the limb is noted in seven cases; in five it was slightly flexed, in two nearly straight; in one case supinated, in the others midway between pronation and supination, or slightly pronated. The general appearance of the region probably resembles that of dislocation of both bones backward, for in three of the cases the anterior position of the radius was not noticed until after the ulna had been reduced. Excluding the two fatal cases, the displacement of the ulna upward is still very marked; four centimetres in Tillaux's case, two or three finger-breadths in Michaux's, and one and a half inches above the condyles in Scott's; in Tillaux's it was also displaced somewhat to the inner side. In three cases the position of the radius is exactly noted; in two, Bulley, Tillaux, it was in the coronoid fosssa; in one, Mason, it rested on the outer portion of the humerus.

Active movements, both flexion and rotation, are impossible, and passive movements restricted and painful.

In two cases, Mayer, Tillaux, reduction failed, the attempt being made on the fourteenth and eighth days respectively. In both the joint remained quite stiff. In Mason's the attempt was made on the nineteenth day; prolonged efforts under ether brought the ulna into place, but the radius slipped toward the outer side and could not be entirely reduced. The final result is not known. In the others reduction was effected without much difficulty, usually the ulna first, then the radius, but in Bulley's the radius remained a little forward, and was finally reduced by continuous pressure upon it.

Treatment.-Traction should be made in the direction of the axis of the forearm to bring the ulna into place, and in case of need it might be well to combine it with some outward lateral flexion to avoid the opposition of the external lateral ligament; after the ulna is reduced the radius should be pressed back into place with the thumbs aided by pronation and adduction of the forearm. It is quite likely that the return of the radius to its place may be impeded by the interposition of the annular ligament.

B. Transverse-Of this variety there is, as above stated, only one recorded case, Guersant's. It is as follows: The patient was a boy fifteen years old, who fell from a tree, three or four metres, on his left side, striking on the palm of his hand. The elbow was enormously swollen; its transverse diameter was greatly increased, and the anteroposterior one seemed lessened. The head of the radius formed a considerable prominence entirely to the outer side of the epiphysis of the humerus and a little upward along its outer border. It was so far displaced outward that there seemed to be an interval betweeen it and the epicondyle; the skin was very tightly stretched over it.

The olecranon was displaced inward behind the epitrochlea, which it embraced in its sigmoid cavity. In the great space between the olecranon and radius lay almost the entire articular surface of the humerus.

The forearm was semi-flexed, and in a position midway between pronation and supination; voluntary movements were impossible, passive movements very restricted. There was also a fracture of the forearm three centimetres from the wrist.

CHAPTER XX.

DISLOCATIONS AT THE ELBOW.-(Continued.)

ISOLATED DISLOCATIONS OF THE ULNA AND RADIUS.

DISLOCATIONS OF THE ULNA ALONE.

Sédillot, in a paper presented to the Académie des Sciences in 1837, was the first of modern writers to call attention to this class of dislocations, although Sir Astley Cooper had previously described as of this kind a specimen preserved at St. Thomas's Hospital. Malgaigne and other surgeons and writers have strenuously opposed the interpretation of cases cited in support of the claim that the occurrence of this form is possible, and have denied the possibility on anatomical grounds, claiming that the ulna cannot be displaced backward and upward unaccompanied by the radius, except after rupture of the interosseous ligament and those uniting the lower ends of the bones, of which there is no clinical evidence. The specimen figured and described by Cooper is claimed by them to be one of dislocation backward of both bones, and one presented by Robert to the Société de Chirurgie, in 1847, was declared by Malgaigne to be of the same character. Malgaigne admits, however, on the authority of a case observed by himself, the possible dislocation of the ulna alone backward and to the outer side behind the radius. The dispute is in part one of terms; it must be admitted, I think, that the head of the radius in some of the reported cases has changed its relations with the capitellum, but the change is a very slight one, a simple slipping backward or forward for a distance of a few millimetres, without a change in its level corresponding to that of the ulna. The erroneous belief in the impossibility of the occurrence without the extensive lacerations mentioned arose apparently from a failure to consider the effect of a change in the relation of the axes of the arm and forearm, for while the occurrence of an isolated dislocation of the ulna backward and upward might be impossible while those relations remained unchanged, yet if, the joint being extended, the forearm is adducted, turning upon the head of the radius as a centre, the olecranon must necessarily move upward behind the humerus; or, the joint being flexed at a right angle, the same movement of adduction or the equivalent outward rotation of the humerus will displace the olecranon backward.

The following recorded cases serve as the basis of the description to be given. Some in which the correctness of the diagnosis is in doubt, or of which I have not been able to consult the detailed reports, have been omitted.

Cooper, Dislocations and Fractures, Amer. Ed., 1844, p. 390; Boudant, Revue Médicale, 1830, vol. 1, p. 75, quoted in full by Sédillot;