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

  • Luther Holden
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.

    2/4 (page 80)
    nnd that it requires a very considerable force to pull it out. The precise amount of this force can be readily estimated by ascertaining the superficial area of the acetabulum, and allowing 15 lbs. for every square inch of surface. But with- out making any such calculation, it may be asserted that the amount of at- mospheric pressui’e is more than suffi- cient to sustain the weight of the entire limb when freely suspended in the air. Now tlie object attained by the limb being held in its socket by atmospheric pressure, is, the saving of muscular ex- ertion in locomotion. The head of the femur, supported by the air, moves with the greatest freedom, and with the least possible amount of friction, in the aceta- bidum; so that, in walking, the hinder leg, once raised from the ground, swings, by the mere force of its own weight, in advance of the other. During this spon- taneous movement of the leg, all its muscles are in a state of complete re- pose. This fact explains, what is matter of common observation, whv a man can walk, during a given number of hours, with less fatigue than it would cost him to stand still. Such being the organization of the hip-joint, one might suppose that the range of its motion would be ahnost as free as that of the shoulder. But, since this would ill accord with the seciuity of the erect postime, we find that nature has restricted its motion in certain di- rections by means of ligaments extend- ing fr-om the pelvis to the thigh. Of these there are two,—the capsular and the round. The capsular ligament not only serves to strengthen the joint, but plays a most important pai'tin restricting the motions of the thigh. In a general way, it may be said that the upper end is attached round the mai’gin of the acetabulum, and tbe lower to the base of the neck of the femur; not, however, round its entire circumference, as is commonly described, but only along its front and upper paii. At its back part tbe capsular ligament simply embraces the neck in the same manner as the annular ligament em- braces the head of the radius. Now the anterior part of the capsule is re- markably thick and strong. It is, in- deed, the strongest ligament in the body, —stronger than the tendo AchUlis or the ligamentum patella). To understand its purpose and design, we should observe that it descends from the up]>er part of the circumference of the acetabulum, downwards and outwards to the anterior iuter-trochanteric ridge of tbe femur, this ridge being yoecially intended for its attachment. In the erect posture, this pai-t of the capsule is fully on the stretch, and therefore it limits any back- ward movement of the thigh on the jiel- vis, or of tbe pelvis on the thigh. Be- sides, however, its power of limiting backward movement, a glance at its at- tachment shows that it limits adduction of the thigh,—in otlier words, it prevents the pelvis from rolling towards the op posite side, while we are standing on one leg; and in this latter respect it co-operates, as will be seen presently, with the Ligamentum teres. , The posterior part of the capsular li- gament, which simply embraces the neck of the femur, may very properly be called the annidar ligament of the hip. One sees clearly wliy it should not have been attached to the femur; for, had it been so, it must of necessity have pre- sented an obstacle to the free bending of the pelvis on the thigh,—as, for in- stance, in sitting or stooping. Lastly, we have to consider the action of the ligameutum teres. This is placed inside the acetabulum, and it is attached respectively to the borders of the aceta- bular notch and to the head of the fe- mur. Its presence in the acetabulum would have prevented the accurate adap- tation of the ball and socket, if the bot- tom of tbe socket had not been exca- vated expressly for its reception and free play. The room not occupied by the ligament is filled up by soft fat, wbich serves merely a mechanical pur- pose. The reason why anatomists have been generally misled as to the use of the round ligament, is, that they have not properly calculated tbe true inclination of the pelvis, and consequently the pre- cise direction of the ligament in the erect postime. Tbe pelvis in the erect attitude is so inclined, that it forms with the horizon an angle of 60°. Now if a pelvis be held at this angle, we find that the notch to which the ligament is at- tached will be at tbe lowest part of the acetabulum. Again, by making a ver- tical section through the head of tlio femur, we may ascertain that the liga- ment, in the erect position, is not only vertical, but fully on the stretch. Con- sequently its action is to assist the an- terior part of the capsule in preventing