1857TurnerW

 

The fragment from Sir William Turner's Human Anatomy and Physiology narrates the involvement of the ligamentum capitis femoris (LCF) in distributing loads across the femoral head (1857TurnerW). The author, nearly two centuries ago, described the exceptionally important role of this structure - «interarticular or suspensory ligament». Unfortunately, this opinion was ignored by subsequent researchers of the biomechanics of the hip joint. 

CHAPTER III. JOINTS AND LIGAMENTS, pp. 41-46.

Divisions of the Moveable Joint — The two chief varieties of the moveable joint are the ball and socket and the hinge.

The best examples of the Ball and Socket are seen in the hip and shoulder joints: the hip is the more perfect of the two, because the cavity into which the globular head of the thigh bone is received is deeper than the cavity that receives the head of the arm bone. In both joints, when fresh, the hollow or socket is deeper than when the dry bones merely are examined, for there is attached to the margin of the hollow a fibrous ring, which, by projecting outwards for some distance, adds considerably to its depth. This embraces the heads of the bones, and assists greatly in keeping them in their position.

In Fig. 1, q. and p. represent the outer surfaces of the shoulder and hip joints.

The ligament that especially characterizes this form of joint is the membranous or capsular. It completely surrounds the articular surfaces of the bones, enclosing them, as it were, in a bag. It is connected by one extremity to the outer surface of the socket, whilst by the other it firmly embraces the constricted part, or neck of that bone on which the head is situated. This kind of ligament allows great extent of movement to take place in the joint, the ball or head of the long bone being permitted to roll about in every direction. The ball and socket joint may be very fully illustrated by examining the hip-joint.

Fig. 3 represents a vertical section of the right hip-join, to show its internal structure.

a. Articular Cartilage.

b. Synovial Membrane.

c Capsular Ligament.

The synovial membrane may here be traced lining the inner surface of the ligament, and covering the articular cartilage. In this joint the capsular ligament is not the only agent which retains the bones in their proper position, for the fibrous ring, before described as deepening the socket, closely clasps the articular end of the thigh bone, and thus materially assists in retaining the articular surfaces closely together. The action of this fibrous ring has been compared by some anatomists to that of the common leather sucker employed by boys for raising stones or other weights from the ground. It so closely embraces the thigh bone that neither air nor fluid are permitted to he between the articular surfaces. Hence the pressure of the atmosphere acting upon the exterior of the thigh, forces the ball into the socket, and keeps it there.

In the interior of the joint is a strong band of fibres called the interarticular or suspensory ligament (d.) This is connected by its upper end to a depression a little above the centre of the head of the thigh bone, by its lower end to the lower margin of the great hollow (acetabulum) in the haunch bone, which receives that head.

When a person is standing erect, or with the body slightly bent, a portion of the weight of the trunk is borne directly by the heads of both thigh bones, or of one thigh bone, according as he stands upon one or both legs, owing to the direct pressure of the acetabula upon the heads of those bones. Now, as the end of this ligament that is connected to the lower margin of the acetabulum is much lower than the end connected to the thigh bone, it of necessity suspends that portion of the weight of the body which is thrown upon it.

The effect of this is, to distribute over the head of the thigh bone that weight which, supposing the suspensory ligament had not been present, would have been sustained by that portion merely which is in direct contact with the upper part of the acetabulum.

The hip and shoulder joints possess very extensive movements. Of the two the hip is the least moveable, because upon these joints the whole weight of the body is thrown in the act of standing, so that, having to bear at times considerable pressure, they are required to be of a deeper and firmer construction than the shoulder. Hence, in them we find the bones much larger, the sockets for the reception of the heads much deeper, and the connecting ligaments much more tense and strong. The shoulder, on the other hand, in order that free play may be given to the arms, has a shallow socket, and a capsular ligament, which is much more lax than the corresponding structure in the hip.

The Hinge Joint has its best representative in the elbow. The knee-joint and the joints of the fingers and toes also present examples of it.

The kind of ligament that more especially characterizes this form of joint is the lateral ligament; so that in all hinge joints strong ligaments may be found on each side. These vary slightly in their shape, some being flat, others rounded; but they all agree in this respect, that they possess great strength. They are connected by their extremities to projections at the sides of the ends of the bones* which they bind together. It is essential to the proper working of the hinge, that the surfaces should move backwards and forwards upon each other, without any lateral displacement taking place. This is attained by the mode of connection of the strong lateral ligaments. The knee-joint, from its great size, possesses very well marked lateral ligaments.

Fig. 1 (m.) gives the external appearance of the elbow-joint.

Fig. 4 exhibits the appearance of the interior when the ligament in front it cut across.

a. Articular Cartilage,

b. Synovial Membrane.

Although the ends of three bones,

h. Humerus,

u. Ulna,

r. Radius,

are seen, yet it is only between two of them, the humerus and ulna, that the proper movements of the hinge are performed; these performed are forwards, termed flexion, and backwards, termed extension. The accuracy of these movements is insured by the presence of a pulley-like surface on the humerus at a, to which a ridge on the articular surface of the ulna closely corresponds, fitting into it, and moving readily in it in the backward and forward action of the joint.

The radius, from its close connection to the ulna, mores backwards and forwards along with it, yet it cannot be said to form an essential part of the hinge. It possesses, however, a very beautiful movement of its own upon the ulna, for its head is closely confined within a ring, represented in Fig. 5 (a.), formed partly of a smooth concave surface on the outer side of the ulna, and partly of a strong annular ligament connected to the ends of this surface: within this ring the head of the radius rolls.

The movement between these bones is effected when the hand, placed on a flat surface, with the palm downwards, is turned so that the palm looks upwards; this is called supination of the hand and fore-arm. When the hand is again returned to its original position, the movement of pronation is performed. The joint between the upper ends of the radius and ulna la not, however, the only one concerned in the production of these movements. For a corresponding joint exists also at their lower extremities; only at this latter joint tie radios has the concave surface, to which a convexity at the end of the ulna corresponds. The radius is the moveable bone, the ulna remaining in its position. So that, owing to the exactly opposite arrangement of the articular extremities of the two bones, daring pronation and supination, whilst the upper end of the radios rolls in the cavity of the ulna, its lower end may be regarded as revolving around the convexity of the ulna. The steadiness and delicacy of these movements are also increased, when the elbow is bent, by the cap-shaped cavity at the head of the radius receiving the small rounded surface of the part of the humerus corresponding to it. A sort of central point or axis is thus afforded, upon which the movements take place. Hence, when it is necessary to perform any movement with the fore arm, in which pronation and supination are to be called into action, and which requires either strength or precision for its execution, the elbow is always bent, for the radius now possesses a fixed point upon which it can move. This may be illustrated by the common operation of inserting a corkscrew into a cork. This is effected by the alternation of these two movements, and, as may readily be ascertained by trying it, is much more easily done when the arm is slightly bent, than when it is extended.

There is no movement, between the two bones of the leg, corresponding to that of pronation or supination performed by the two bones of the fore arm; for the leg, being for the purpose of supporting the weight of the body, it is necessary that it should be strong and steady. Hence the joints between the upper and lower ends of the tibia and fibula are of such a nature as to allow scarcely any movement at all to take place between the two bones.

Owing to the ligaments connecting the different bones in a finger being lateral ligaments, the movements possessed by these bones are flexion and extension. These kinds of movements, together with the numerous joints, eminently adapt the hand for the performance of its various duties. Thus, the diffident joints in the fingers can be so bent that each finger may be made to assume the form of a hook; the bending of the whole of the fingers, in this hook-like manner, enables us to suspend the whole weight of the body upon an object grasped by them. The movement that especially characterises the hand of man is that of opposition; that is, by which the thumb can be made to oppose or touch any part of the palmar surface of the hand and fingers. This gives to the hand unusual power in grasping objects, and compressing them, if needful, with great force, whilst this force can be so nicely regulated, that movements requiring the most delicate manipulation can be undertaken with equal readiness.

References

Turner W. Atlas and Handbook of Human Anatomy and Physiology. Edinburgh: W. & A.K. Johnston, 1857. [archive.org , books.google]

Authors & Affiliations

William Turner (1832–1916), was a demonstrator of anatomy and Professor of Anatomy at the University of Edinburgh, the Principal of the University of Edinburgh from 1903 to 1916. [wikipedia.org]

Sir William Turner (1881)

The author of the image is G. Jerrard;

Original in the wikimedia.org collection (CC-BY-4.0, no changes)

Keywords

ligamentum capitis femoris, ligamentum teres, ligament of head of femur, anatomy, role, significance, biomechanics

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