ABSTRACT.

The points which were new to science in the first edition are here printed in italics.

1. The anterior part of the capsule of the hip joint is a triangular ligament of great strength, which, when well developed, exhibits an internal and external fasciculus, diverging like the branches of the inverted letter Y. It rises from the anterior inferior spinous process of the ilium, and is inserted into nearly the entire length of the anterior intertrochanteric line.

2. The Y ligament, the internal obturator muscle, and the capsule subjacent to it, are alone required to explain the usual phenomena of the regular luxations.

3. The regular dislocations are those in which one or both branches of the Y ligament are unbroken; and their signs are constant.

4. The irregular dislocations are those in which the Y ligament is wholly ruptured; and they offer no constant signs.

5. In the regular dislocations of the hip, the muscles are not essential to give position to the limb, nor desirable as aids in its reduction.

6. The Y ligament will alone effect reduction and explain its phenomena, a part of those connected with the dorsal dislocations excepted. During the process of reduction, this ligament should be kept constantly in mind.

7. The rest of the capsule, except perhaps that portion beneath the internal obturator tendon, need not be considered in reduction, if the capsular orifice is large enough to admit the head of the femur easily.

8. If the capsular orifice is too small to allow easy reduction, it should be enlarged.

9. The capsular orifice may be enlarged at will, and with impunity, by circumduction of the flexed thigh.

10. Recent dislocations can be best reduced by manipulation.

11. The basis of this manipulation is flexion of the thigh.

12. This manipulation is efficient either by one method, because it relaxes the Y ligament, or by another method, because that ligament, remaining tense, is a fixed point, around which the head of the femur revolves near the socket.

13. The further manipulation of the flexed thigh may be either by traction or rotation.

14. The dorsal dislocation owes its inversion to the external branch of the Y ligament.

15. The so-called ischiatic dislocation owes nothing whatever of its character, or its difficulty of reduction by horizontal extension, to the ischiatic notch.

16. The ischiatic dislocation is better named dorsal below the tendon, and is easily reduced by manipulation. But the term "ischiatic" might better be suppressed. It is the dorsal dislocation with the least shortening.

17. The flexion of the thyroid and downward dislocations is due to the Y ligament, which, in the first, also everts the limb, until the trochanter rests upon the pelvis.

18. In the pubic dislocation, the range of the bone upon the pubes is limited by this ligament, which, in the sub-spinous dislocation also, binds the neck of the femur to the pelvis.

19. In the dorsal dislocation with eversion, the outer branch of the Y ligament is ruptured. In the absence of this fulcrum, this dislocation may need pulleys for its reduction.

20. In the anterior oblique luxation, the head of the bone is hooked over the entire Y ligament, the limb being then necessarily oblique, everted, and a little flexed.

21. In the supra-spinous luxation, the head of the femur is equally hooked over the Y ligament, the external branch of which is broken. The limb may then be fully extended.

22. In old luxations, the period during which reduction is possible is determined by the extent of the obliteration of the socket, the strength of the neck of the femur, and the absence of osseous excrescence.

23. Old luxations may possibly require the aid of pulleys, in order by traction to avoid any danger which might result to the atrophied or degenerated neck of the bone from rotation.

24. Right-angled extension, the femur being flexed at a right angle with the pelvis, is more advantageous than that which has usually been employed.

25. To make such extension most effective, a special apparatus is required.

FRACTURES OF THE NECK OF THE THIGH-BONE.

1. The terms "intra" and "extra" capsular, applied to these fractures, have little practical significance, because when a fracture near the head of the femur shows bony union, it is often impossible to say whether such a fracture was originally inside or outside the capsular ligament.

2. These fractures are therefore better divided, for practical purposes, into (1) the impacted fracture of the neck into the trochanter; and (2) other fractures of the neck.

3. In this impacted fracture, the limb is everted because the posterior cervical wall is almost always impacted, the anterior very rarely, and in a less degree.

4. These conditions mainly result from the relative thickness of the two walls.

5. While eversion is due to the rotation of the fractured bone on a hinge formed in the anterior cervical wall, shortening is generally due to the obliquity of this hinge.

6. In a well-formed bone, the posterior and thin surface of the neck of the femur is prolonged into the cancellous structure beneath the intertrochanteric ridge, and is the true neck.

7. The posterior intertrochanteric ridge is a buttress built upon the true neck, by which, when impacted, this ridge is sometimes split off.