182 THE ARTICULATIONS OF THE LOWER LIMB. 



ference of the cotyloid cavity, but pass obliquely from without inwards over its 

 margin, one extremity being attached to the outer, the other to the inner surface. 



At the cotyloid notch the fibres of the ligament are continued from side to side, 

 so as to render the circumference complete, and deeper transverse fibres are super- 

 added, from which circumstance, as well as from being stretched across from one 

 margin of the notch to the other, this part is called the transverse ligament. Beneath 

 it an interval is left for the admission of the articular vessels. 



The interarticular or round ligament (ligamentum teres) is a variable fas- 

 ciculus surrounded by synovial membrane, attached by one extremity, which is 

 round, in the fossa on the head of the femur ; by the other, which is broad and 

 flat, to the transverse ligament and the margins of the cotyloid notch, the strongest 

 fibres passing to the ischial border. It rests on the fat in the fossa acetabuli. 



The capsular ligament surrounding the joint is attached above to the margin 

 of the cotyloid cavity, and below to the neck of the femur. At its cotyloid attach- 

 ment the capsule arises, above and behind, from the bony margin outside the 

 attachment of the cotyloid ligament, having its inner surface in close contact with 

 that ligament ; in front it arises from the outer aspect of the cotyloid ligament near 

 its base, and at the notch it is similarly attached to the transverse ligament. At its 

 femoral attachment the capsule extends anteriorly to the intertrochanteric line, 

 superiorly to the root of the great trochanter, posteriorly and inferiorly to the 

 junction of the middle and external thirds of the neck. The fibres of which the 

 capsule consists run in two directions, circularly and longitudinally. The circular 

 fibres are most distinct at the lower and posterior part of the capsule, where they are 

 collected into a band about half an inch in breadth, which embraces the neck of the 

 femur ; above and in front they spread out and become inter ivoven with the deeper 

 layers of the strongly developed longitudinal fibres, by which they are thus con- 

 cealed. The longitudinal fibres on the posterior aspect of the joint are almost 

 absent, being represented only by a few scattered fibres which support the synovial 

 membrane, and attach the circular fibres to the neck of the femur. In other parts 

 of the capsule the longitudinal fibres form thick bands, certain of which from their 

 greater size and strength are distinguished as accessory ligaments. The most 

 important of these is formed on the antero-superior aspect of the capsule and is 

 known as the ilio-femoral ligament (fig. 204, 8). This springs above from the lower 

 part of the anterior inferior iliac spine, and behind this from an impression on the 

 bone immediately above the margin of the acetabulum ; the fibres diverge and form 

 two strong bands, the inner of which passes almost vertically to the lower part of the 

 anterior intertrochanteric line, the outer to the upper part of the same line and the 

 adjacent part of the neck of the femur. Between the two bands is a thinner part of 

 the capsule ; but it not unfrequently happens that the division is not marked, so 

 that the ligament forms one flat triangular band, attached by its base to the whole 

 length of the anterior intertrochanteric line. 1 At the lower and hinder part of the 

 joint, a broad and strong band of fibres, the ischio-capsular ligament, passes from the 

 furrow on the ischium below the acetabulum to end in the circular fibres. In front 

 and below may be also found a number of scattered fibrous bundles, which converge 

 to the capsule from the ilio-pectineal eminence, from the obturator crest, and from 

 the obturator membrane, constituting the pulo-femoral ligament. Besides these 

 the capsule receives above other strengthening bands from the tendon of the posterior 

 head of the rectus femoris, and from the gluteus minimus. 



From the inside of the capsule the innermost fibres are reflected upwards from 



1 The outer or tipper of these bands is sometimes described separately as the ilio-trocliantcric 

 ligament ; and the whole structure is frequently designated by surgeons the Y ligament of Bigelow. 



