It may, however, be briefly stated that the gemelli are practically identified with the obturator internus, while the obturator externus below it and the pyriformis above it are also outward rotators, the whole forming a deep muscular layer with interstices. The quadratus femoris muscle is below the usual range of dislocations, but is easily and frequently torn; and the three glutei have comparatively little efficacy in rendering the femur immovable, even when its head is engaged, for example, beneath the medius. The psoas and iliacus exert a force in the direction of the Y ligament, especially when that is ruptured; and if the limb is elongated, the adductors, the flexors of the leg, the tensor vaginæ femoris, and the muscular fibres arising from the anterior part of the crest of the ilium, may all become more or less tense.1

DISLOCATIONS.

MALGAIGNE is undoubtedly right in assuming that dislocation of the hip is sometimes only partial. These various degrees of dislocation give to the limb the slight differences of position observed in different cases of the same luxation. But the observation is not new. Hippocrates, in speaking of dislocation of this joint, remarks: "In a word, luxations and sub-luxations take place in different degrees, being sometimes greater and sometimes less."2 Yet it cannot be denied that the general character of the deformity is the same for the same dislocation, and that the phenomena were on the whole well described by Cooper, and by preceding writers from the

1 In a case of persistent flexion after reduction, I divided these fibres. (See p. 55 of this volume.)

2 The Genuine Works of Hippocrates, etc. (vol. ii. p. 631). Printed for the Sydenham Society. London, 1849.

time of Hippocrates,1 in three or four now familiar varieties, with three or four rarer forms of displacement considered to be anomalous.

Accumulated experience has justified the practical value of this general division, which should not be lost sight of either by exaggerating unimportant differences, or through needlessly obscuring what is plain by names of recondite derivation. Most surgeons have seen these dislocations in the living subject, and although the rotation, the shortening, or other displacement may have varied a little in each case, will concede that the general position of the limb is too constant and characteristic to be slighted either as a guide to the direction of the luxation, or to the force appropriate for its reduction. I have therefore adhered as far as possible to the familiar names of hip luxation, which as usually designated are those upon the dorsum, the ischiatic notch, the thyroid foramen, and the pubes. Great stress having been laid by most modern writers on a distinction between the first two, which if reduced by the flexion method are wholly unimportant variations of the same displacement, I shall endeavor to show how dorsal dislocations may be divided for practical purposes; also, that certain other less frequent luxations, hitherto classed as anomalous, are determined by the same mechanism as the rest, and with equal certainty.

Assuming that the Y ligament exerts a uniform influence upon the several dislocations, they will be here described with a view to their practical arrangement, according to the following classification:

1 Hippocrates describes the luxations on the dorsum, thyroid foramen, and pubes, justly including with the first variety that which has since been called "dislocation upon the ischiatic notch," most of the cases so described by modern writers being only dorsal. In a fourth variety, the dislocation "backward," which has been, as I conceive, erroneously interpreted by his translators as "into the ischiatic notch," - Hippocrates describes at some length the dislocation directly downward.

I. THE REGULAR DISLOCATIONS, in which one or both branches of the Y ligament remain unbroken.

1. DORSAL.

2. DORSAL BELOW THE TENDON (ischiatic notch of Cooper).

3. THYROID AND DOWNWARD.

Obliquely inward on the thyroid foramen, or as

far as the perinæum.

Vertically downward.

Obliquely outward as far as the tuberosity.

4. PUBIC AND SUB-SPINOUS.

5. ANTERIOR OBLIQUE.

6. SUPRA-SPINOUS.

7. EVERTED DORSAL.

External branch broken.1

Both branches entire.

II. THE IRREGULAR DISLOCATIONS, in which the Y ligament is wholly ruptured, and whose characteristic signs are therefore uncertain.

GENERAL REMARKS UPON REDUCTION.

When the patient lies upon his back, especially if etherized, the dislocated limb gravitates, and the Y ligament becomes more and more tense as the limb approaches nearer and nearer

cases.

1 Although the anterior-oblique, supra-spinous, and everted dorsal luxations resemble one another, it has been thought advisable to distinguish between them for the purpose of more accurately classifying recorded In the anterior oblique luxation the outer branch of the Y ligament is still entire, as seen in the figure illustrating this luxation, where the ligament is of uniform thickness. This, indeed, is a form of supraspinous luxation; but the limb cannot be brought down to a perpendicular, and corresponds in position with that in a case reported by Cooper. If the limb is forcibly brought to a perpendicular, the external branch is ruptured; and to such a case the term "supra-spinous" is here assigned. The term "everted dorsal " is intended to imply a power of eversion more or less complete. In such a case the limb may be everted at various angles, which can happen only after a rupture of the external branch of the ligament.

to a state of complete extension. If, now, as is here maintained, the chief obstacle to reduction of the luxated hip is found in this ligament, it follows that the method taught by Sir Astley Cooper, the weight of whose unquestioned authority has unfortunately availed to give it currency1 during many years, is based upon an erroneous conception of the nature of the difficulty to be encountered. By that method the limb is placed as nearly as may be in the axis of the body, thus rendering the Y ligament tense, and inviting its maximum of resistance before traction is made. Hence the necessity for pulleys, the tendency of which is undoubtedly to elongate or partly detach, at its femoral insertion, this powerful ligamentous band, at great sacrifice of mechanical force, with proportionate violence to the neighboring tissues and uncertainty as to the result. By the flexion method, which dates from a remote antiquity, the Y ligament is relaxed, its resistance annulled, and reduction often accomplished with surprising facility.

The following is the statement of Hippocrates on this subject:

"In some the thigh is reduced without preparation, with slight extension, directed by the hand, and with slight movement; and in some the reduction is effected by bending the limb at the joint, with gentle shaking." 2

1 See Edinburgh Medical Journal, May, 1867, "On the Reduction of Dislocations of the Hip-joint by Manipulation." By Thomas Annandale, Lecturer on Surgery, etc. "Its adoption in this country [reduction by manipulation] is as yet by no means general."

2 Dr. Adams, in his Sydenham Translation of Hippocrates, renders this passage, "bending the limb at the joint, and making rotation” (vol. ii. p. 643). Mr. Sophocles, the distinguished Professor of Greek in Harvard University, has kindly furnished me the following conclusive note, defining precisely the character of this movement:

"Your question has reference to the meaning of the word Kiykdıσis, the formation of which is as follows: Kiykλos, wag-tail, a well-known

In view of this observation of the Coan sage (450 B. c.), the indiscriminate use of pulleys hardly testifies to the progress of modern science.

Flexion lies at the foundation of success in the reduction of femoral dislocation; and compared with this the rest of the manipulation is of secondary importance. It may be taken as a safe and general rule that after the thigh has been flexed at a right angle the head of the bone is to be at once guided toward the socket, and that if the capsular orifice is large enough the operator will in general succeed; while it is equally certain that in the extended position of the limb the chances are all against him. When the femur is flexed, reduction may be effected in either of two ways. In the first (traction) the head is drawn or forced at once in the desired direction; in the second (rotation) the same result is accomplished by a rotation of the femur, which, in winding1 the Y ligament about its neck, shortens it, and thus compels the head of the bone, as it sweeps round the socket, also to be guided toward the socket. In reducing a hip, the success of rotation, adduction, abduction, and extension depends upon this ligament, while the whole manipulation must be conducted with reference to it.

In modern times the flexion method has commended itself to the good judgment of various surgeons. Many cases of successful reduction by this method are to be found in the

bird in Greece, called also σetoonvyis, the Latin motacilla, Kıykλičw, to wag (in the original sense of the term), as the bird aforesaid wags its

tail.

66

Κίγκλισις and κιγκλισμός, a wag-tail movement, or shaking rapidly within narrow limits; gentle shaking. The words circumaction and rotation are out of the question, for the former is περιαγωγή, and the latter κυκλοpopía, — unless rotation be used in a peculiar sense.

"Erotian, in his Hippocratic Glossary, and Galen, define κɩyêλɩσμós, the synonym of κίγκλισις, by βραχεία κίνησις, short motion, like that of the tail of the bird that furnishes the word."

1 See Fig. 24.