socket shall correspond to the hollow beneath the neck of the femur. With some force the thigh can now be everted, and afterward brought down across the upper part of its fellow. It is here firmly locked, with great shortening and some eversion, the limb facing forward and obliquely crossing the opposite thigh, while the toe points outward, a position not wholly ungraceful, and suggesting some attitudes in dancing. (Figs. 32 and 33.) 1

If in this position it is desired to bring the limb toward a perpendicular, the outer branch of the Y ligament must be ruptured. Thus liberated, it hangs suspended by the inner ligament, and becomes capable of lateral motion and of rotation; and this is probably the condition under which supraspinous luxation, although rare, usually occurs. (Fig. 35.)

The anterior oblique dislocation may be reduced by inward circumduction of the extended limb across the symphysis, with a little eversion, if necessary, to disengage the head of the

1 For a description of the annexed woodcut, taken from Cooper, and which exhibits the position of the anterior oblique luxation, see case of Oldknow (Guy's Hospital Reports, No. 1, p. 97), also Cooper ("Treatise,' etc., Case LXVII.). The foot is said to have been very much everted, only the toes touching the ground. But the patient had lived twelve years after the accident, and something may be allowed for pathological changes. For a larger figure representing this dislocation, see a paper of Bransby Cooper, Guy's Hospital Reports, 1836, vol. i. p. 81.

FIG. 34.(a)

(a) Anterior oblique luxation.

bone. Inward rotation then converts this into the common luxation upon the dorsum.

SUPRA-SPINOUS DISLOCATION.2

THE head of the bone has been found above the inferior spinous process, the neck lying across the edge of the pelvis, the trochanter turned back, and as is said not readily discovered. The limb was shortened two or three inches, a

1 This figure is intended to show in diagram the external portion of the Y ligament detached, as in the supra-spinous and everted dorsal luxations.

2 See case of Cummins (Guy's Hospital Reports, vol. iii.). Cooper ("Treatise," etc., Case LXV.) cites this case as anomalous, illustrating it with a figure which represents the head of the bone as projecting farther upon the abdomen than the context indicates. The leg was shortened three inches, and could not be drawn down. The limb, which

little abducted, and everted, - this eversion being sometimes so great that the toes pointed backward, although in one of

was much everted, could not be rotated inward. Cooper considers this to be "a variety of dislocation hitherto unknown."

Travers (Medico-Chirurgical Transactions, vol. xx. p. 113) thus describes a case: "The trochanter is felt below and to the outer side of the anterior superior spinous process of the ilium. The neck of the bone lies apparently between the two anterior spinous processes, so that when the patient is erect the limb seems as it were slung or suspended from this point."

Sir Astley Cooper ("Treatise," etc., Case LXII.) cites a case of old dislocation "on the pubes." An

accurate account of the autopsy, with the annexed figure, is given by N. Cadge, F. R. C. S., Norwich (Medico-Chirurgical Transactions, vol. xxxviii. p. 88). The left leg was full an inch and a half shorter than the right; the toes were turned outward; and while the body lay on its back the foot rested completely on the outer border. A large, globular, bony tumor was felt in the groin, close to the superior spine of the ilium. On dissection, the head of the femur was found in the interval between the anterior superior and anterior inferior spinous processes of the ilium. The head of the femur was covered with a complete bony cap, lined with a dense, pearlywhite tissue, resembling fibro-cartilage (Fig. 36). The edge of the new cavity was connected with the neck of the thigh-bone by a thick capsular ligament. The rectus muscle, which had been torn from its origin, was inserted into the edge of the new cavity, a condition that suggests the ascent of the bone above the inferior spinous process of the ilium at the time of the injury, with rupture of the Y ligament. This luxation may have been supra-spinous or irregular.

(a) Supra-spinous dislocation. a, bony cap; b, fractured margin of ditto; c, socket; d, superior spinous process of ilium.

the cases related by Cooper they could be brought forward again to the side of the other foot. Another important feature was that the shortened limb could not be drawn down.

In this luxation the neck was doubtless hooked over the Y, and perhaps over the tendon of the rectus muscle also; so that direct extension, short of the rupture of this ligament, was worse than useless. The head of the bone had been thrust above and outside the Y ligament, upon which in its return the neck of the femur had engaged itself, the main

branch of the Y then lying behind the neck, and so wound around it as to produce great shortening.

In the supra-spinous luxations eversion is due to the internal obturator, when it remains entire, but also to the tense ligament.

1 Figs. 37 and 38,- supra-spinous dislocation. (See note, p. 88.)

The muscles inserted into the back of the trochanter, especially the obturator internus, hinder the head of the bone from advancing upon the spinous process; but when they are divided, the head advances toward the abdomen. The first degree of supra-spinous luxation, which is represented in the woodcut (Fig. 37),

requires the rupture of only the outer fibres of the Y ligament, and is but a slight exaggeration of the anterior oblique luxation (Fig. 33). But when the bone projects fairly upon the abdomen (as illustrated by the dotted line, Fig. 37), only the inner fasciculus remains.

It may be remarked that the anterior oblique dislocation, while it is also supraspinous, differs from it in

FIG. 39.1

the comparative soundness of the ligament, which compels the limb to assume an oblique position. In the latter luxation the outer band is broken, and the limb is more movable; the term "supra-spinous" has been reserved for this, as probably the more common of these two rare varieties.

1 This woodcut is intended to show the possibility of a posterior oblique luxation, the Y ligament being entire, the head of the bone thrust across it, and the shaft locked behind the tuberosity. In the dissected bones it will be found that the femur is firmly locked, the limb being directed backward, and the foot somewhat everted. But there is no authority, so far as I am aware, to show that such a position of the leg has been found in the living subject. By forcibly advancing the knee the outer branch of the ligament is ruptured, and the luxation then becomes supra-spinous.