On some points concerning the mechanism of the hip-joint / by Luther Holden.

  • Holden, Luther, 1815-1905.
Date:
[1850]
Catalogue details

Licence: Public Domain Mark

Credit: On some points concerning the mechanism of the hip-joint / by Luther Holden. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ON SOME POINTS CONCERNING THE MECHANISM OF THE HIP-JOINT. By LUTHER HOLDEN, Esq. Head on Thursday, November li, 1850. The problem to be solved in the con- struction of the hip-joint is, tliat the joint possess solidity adequate to sup- port the weight of the body, to resist the violent shocks to which it is exposed, and that it be freely moveable in all directions consistent with the require- ments of the lower hmbs. Now these purposes can only be accomplished by a ball-and-socket joint, and such an one nature has made in the very best pos sible manner. By making sections through the fresh joint, it is observed that the respective smTaces of the head of the femur and of the acetabulum form segments of spheres of equal diameters, and that therefore they are accm'ately adapted each to the other. If we institute a comparison be- tween the ball and socket of the hip, and the ball and socket of human con- trivance, the great superiority of nature’s work is at once evident. In the aidifi- cial ball and socket, it is essential that the socket form more than half a circle, else the ball would not be retained in it; the range of motion is therefore neces- sarily limited, since the stem to which the ball is fixed soon comes in contact with the margin of the socket. But the human acetabulum is paid of a cu-cle of less than 180°, and therefore the head of the femur has a very wide range of motion, as one may see in the tiicks of mountebanks, who can raise their legs to their shoulders, and fall on theii’ but- tocks with their legs stretched out at a right angle. In order to deepen the acetabulum, and to render it an-tight, its margin is provided with a ring of fibro-cai-Wage, commonly called the cotyloid ligament. This is a flexible, gi’adually shelving, lip, which, by viidue of its elasticity, em- braces the head of the femur. Its com- ■ponent fibres nm parallel to the margin of the acetabulum, and pass uninter- rupted across the notch at the lower part of it. The use of this elastic ring is to act like a valve or sucker to the acetabulum, and to keep it, as it were, hermetically sealed. The capsule of the hip may be completely distended with fiuid, without any risk of the fluid enter- ing the acetabulum,- so long as the sucker is in proper action. But let ever so smaU a quantity of fluid be secreted within the acetabulum, the consequence is, that the head of the femur ceases to be in accurate contact with its socket; the sucker is presently raised by the junc- tion of the fluid within and without the acetabulum, and thus it happens that the limb not only becomes lengthened, but it may even be spontaneously dislocated, provided the ligaments have sufficiently yielded. In the ball and socket of human con- trivance, it is obvious that the ball is held fast by the constriction of the mouth of the socket itself. But in the hip-joint, the power which holds the head of the femur in the acetabrrlum is atmospheric pressm'e. From the very constniction of the parts, any one in the least degi’ee familiar' with natural philosophy will see at once that it must be so. But it is easily proved by direct experiment. If all the soft paris in- cluding the capsule be removed from the joint, we find that the head of the femm- is still held in the acetabulum,