152 ARTICULATIONS OF THE LOWER LIMB. 



bone. The articulating surface of the acetabuluin is formed by a broad 

 riband-shaped cartilage occupying the upper and outer part, and folded 

 round a depression which, extending from the notch, is hollowed out in the 

 bottom of the cavity, and is occupied by delicate adipose tissue covered 

 with synovial membrane, the so-called synovial or Haversian gland. The 

 articulating surface of the femur presents a little beneath its centre a pit in 

 which the round ligament is attached. 



The cotyloid ligament forms a thick ring round the margin of the aceta- 

 bulum, increasing the depth of its cavity, and bridging over the deficiency in 

 its border. Its external surface is in contact with the capsular ligament, the 

 internal closely embraces the head of the femur, and both are covered by 

 the synovial membrane. Its fibres do not run parallel to the circumference 

 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, aud deeper transverse 

 fibres are superadded, 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. Subjacent to it an interval is left for the 

 admission of the articular vessels. 



The interarticular or round ligament (ligamenturn teres) is a strong fasci- 

 culus surrounded by synovial membrane, implanted by one extremity, which 

 is round, into the fossa in the head of the femur ; by the other, which is 

 broad, flat, and bifid, into the margins of the cotyloid notch, where its 

 fibres become blended with those of the transverse ligament. It rests on 

 the fat in the depression of the acetabulum. 



The capsular ligament, surrounding the joint, is attached superiorly in 

 the greater part of its extent to the acetabulum, within two or three lines 

 from the cotyloid ligament, except at the notch, where it is connected with 

 the transverse ligament. At its femoral border it extends in front as far 

 as the anterior intertrochanteric line, but behind it falls short considerably of 

 the posterior intertrochanteric ridge. Its strongest part is in front, and there 

 its fibres extend vertically from the upper part of the acetabulum to the lower 

 part of the intertrochanteric line, and are strengthened by a firm fasciculus, 

 descending from the anterior inferior spine of the ilium, called the accessory 

 or ilio-femoral ligament. On its superior border the capsule is strengthened 

 by fibres connected with the insertion of the gluteus minimus muscle. The 

 fibres which arise in front of the notch of the acetabulum pass down in 

 front of the small trochanter; those which arise behind the notch pass 

 towards the trochanteric fossa ; and between those two fasciculi, the capsule 

 is extremely weak, and its fibres pass in a circular direction, so that oppo- 

 site the posterior intertrochanteric ridge no fibres are inserted into the neck 

 of the femur, and the reflection of the synovial membrane from the bone to 

 the capsule can be laid bare behind the neck without cutting any part of the 

 capsule. 



The synovial membrane lining the joint and ligament is reflected from the 

 neck of the femur to the inner surface of the capsule ; passing over the inner 

 surface of the capsule to the margin of the acetabulum, it is reflected from 

 that and from the synovial fat as a tubular investment of the round 

 ligament to the head of the femur. 



MOVEMENTS. In the hip-joint movement is allowed in every direction. Extension 

 is limited by the capsular ligament, the anterior fibres of which become tense in that 



