172 



DISSECTION OF THE THIGH. 



Round 

 ligament : 



shape and 



attach- 

 ments ; 



how to see 

 its action ; 



loose in 

 extension ; 



tight in 

 flexion with 

 adduction 

 or rotation 

 outwards. 



Synovial 

 membrane. 



Detach the 

 limb. 



Articular 

 surface of 



Acetabu- 

 lum cartila- 

 ginous 



externally. 



Fat in the 

 bottom. 



Kinds of 

 motion. 



enter the acetabulum to supply the synovial membrane and the fat 

 in the bottom of that hollow. 



The interarticular ligament (ligamentum teres, fig. 65, 6) is a 

 band about an inch long, but of very variable thickness, which 

 connects the head of the femur with the hip-bone. The ligament 

 has a triangular form, the apex of the triangle being fixed to the 

 pit on the head of the femur, and the base joining the transverse 

 ligament. The free sides of the triangle are formed by two fibrous 

 bundles, an anterior or pubic (c), which is attached with the trans- 

 verse ligament to the pubic edge of the cotyloid notch, and a 

 posterior or ischial (d), which is stronger, and is inserted beneath 

 the transverse ligament into the ischial border of the notch. 



To see the condition of the interarticular ligament in the different 

 movements of the joint, it should be examined in a specimen in 

 which the capsule is entire, and the floor of the acetabulum has 

 been cut out with a chisel from inside the pelvis. 



During extension of the joint the ligament is relaxed ; and it 

 cannot be tightened so long as the fully extended position is 

 maintained. 



In flexion of the joint the ligament is rendered somewhat tighter ; 

 but it is only fully stretched when, with the joint bent, the femur 

 is adducted or rotated outwards : the pubic fasciculus of the band 

 is especially tightened by the adduction, and the ischial slip by the 

 outward rotation. 



A synovial membrane lines the capsular ligament, and is continued 

 along the neck of the femur to the margin of the articular surface. 

 In the bottom of the cotyloid cavity it is reflected over the fat in 

 that situation ; and it surrounds 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, and at this stage the pelvic attachments of the interarticular 

 ligament can be better displayed. 



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

 completely covered with cartilage. 



In the head of the femur is a pit into which the round ligament 

 is inserted. 



The acetabulum is coated with cartilage at its circumference, 

 except opposite the cotyloid notch, and touches the head of the 

 femur by this part : this articular surface is deep above, but 

 gradually decreases towards the edges of the notch. 



In the hollow of the cartilage, and close to the notch, is a mass 

 of fat, covering about one-third of the area of the cotyloid cavity, 

 which constitutes the " gland of Havers " : it communicates with 

 the fat of the thigh beneath the transverse ligament. 



Movements. In this ball and socket joint, there are the same 

 kinds of movement as in the shoulder, viz., flexion and extension, 

 abduction and adduction, circumduction and rotation, but all of 

 them, with the exception of flexion, are of a much more limited 

 extent. 



