| 1. Lower thyroid. | - | All present the general characteristics of adduction and rotation outward. | |
| 2. Middle thyroid. | |||
| 3. High thyroid. | |||
| 1. Low dorsal. | - | All present the general characteristics of abduction and rotation inward. | |
| 2. Middle dorsal. | |||
| 3. High dorsal. | |||
The relation of the so-called Y-ligaments to the successful reduction of these dislocations, as well as to their formation, is of considerable importance.
Fig. 355
Upward and somewhat backward on dorsum ilii.
Backward toward sciatic notch.
Downward into foramen ovale.
Forward and upward on the pubic bone.
Dislocations of the head of the thigh bone, according to Astley Cooper’s classification. (Erichsen.)
[Fig. 356] illustrates the manner in which this ligament receives its name, it being simply a reduplication of fibers which strengthen the capsule and which are arranged in the shape of an inverted Y. No matter how serious the injury it is seldom entirely detached. While it prevents too great displacement it is of special service in that it may be made to serve as a fulcrum for the leverage required in certain manipulations. American surgeons are entitled to the credit for the establishment of the importance of this ligament in this consideration, and while Bigelow’s name is most prominently mentioned, the names of Gunn, of Chicago, and Reid and Moore, of Rochester, New York, deserve almost equal prominence, not only for their anatomical studies, but for working out the entire method of manipulation which has completely supplanted the old and more violent methods in which the use of pulleys and tackle was not infrequent. The Jarvis “adjuster,” a powerful mechanism, which was formerly employed for this purpose, is not now seen except in museums.