602 DISSECTION OF THE THIGH. 



two pieces ; and to bring these into view, the synovial membrane and ave- 

 olar tissue must be removed. The transverse ligament over the notch is 

 also to be defined. 



The cotyloid ligament (fig. 191, <JT) is a narrow band of fibro-cartilage, 

 which is fixed to the margin of the acetabulum, and is prolonged across 

 the notch on the inner side, so as to form part of the transverse ligament. 

 Its fibres are not continued around the acetabulum, but are fixed to the 

 margin of the cavity, and cross one another in the band. It is thickest 

 at its attachment to the bone, and becomes gradually thinner towards the 

 free margin, where it is applied to the head of the femur. 



This ligament fills up the hollows in the rim of the acetabulum, and 

 deepens the socket for the femur in the same manner as the glenoid liga- 

 ment increases the surface for the reception of the head of the humerus. 



The transverse ligament (fig. 191, A) is a firm but narrow band, which 

 reaches across the upper part of the notch at the inner side of the aceta- 

 bulum. It consists partly of deep special fibres (h) which are attached to 

 the margins of the notch ; and partly of a superficial bundle from the 

 cotyloid ligament (g). Beneath it is an aperture by which vessels and 

 nerves enter the acetabulum to supply the synovial membrane, and the fat 

 in the bottom of that hollow. 



The inter articular or round ligament (fig. 206, 5) (ligam. teres) is a 

 slight band about an inch long, connecting the femur with the innominate 

 bone. 



One extremity is roundish, and is inserted into the pit in the head of 

 the femur. 



The other is flattened, and divides into two parts opposite the transverse 

 ligament. The anterior piece (r) (pubic) is attached with the transverse 

 ligament to the pubic edge of the notch. The posterior part (rf) (ischial) 

 is inserted behind the transverse ligament into the ischial border of the 

 cotyloid notch. 



Dissection. To see its condition in the different movements of the articu- 

 lation, it should be examined in a joint in which the capsule is entire, and 

 the bottom of the acetabulum has been cut out with a chisel inside the 

 pelvis. 



When the joint is in the extended state, the ligament is generally lax, 

 the two end attachments being near each other ; but if the femur is ad- 

 ducted, the ischial part of the ligament is rendered tight because the head 

 of the femur rises. 



In flexion of the joint the ligament is tighter than in extension, as 

 the femoral insertion is removed from the acetabular ; and if, in the bent 

 state, the femur be rotated out or adducted, the round ligament will be 

 most stretched. 



A synovial membrane lines the capsular ligament, and is continued along 

 it to the acetabulum and the head of the femur. In the bottom of the 

 cotyloid cavity it is reflected over the fat in that situation ; and it sur- 

 rounds the ligamentum teres. 



Dissection. To see the surface of the acetabulum the lower limb is to be 

 separated from the trunk by dividing the interarticular ligament, and by 

 cutting through any parts that connect it to the pelvis : at this stage the 

 pelvic attachments of the round ligament can be better seen. 



Surfaces of bone. The articular surfaces of the bones are not completely 

 covered with cartilage. 



