472 The Knee-joint 



signs of fracture of the femur, shortening and eversion (p. 462), but the 

 dislocated limb is rigidly fixed, the great trochanter is absent from its 

 place, and the head of the femur is felt on the pubic ramus. 



In each dislocation the ilio-femoral ligament remains entire, and. 

 impedes reduction at any rate, when the attempt is made on the old 

 system of extension by pulleys and counter-extension by a band around 

 the perineum. But when the ligament has been first slackened, as 

 occurs when the thigh is flexed, a small amount of movement, if in the 

 right direction, suffices to get the head of the bone in its place again. 

 'After flexion, and perhaps circumduction (to enlarge the rent in the 

 capsule for the return of the femoral head), the reduction may be com- 

 pleted by rotation, or by extension of the thigh ' (Hamilton). This is 

 the anatomical or scientific method of restoring the bone. 



As a result of congenital deformity of the acetabulum, and of the 

 hip-joint generally, the head of the femur rests upon the dorsum ilii, 

 the great trochanter being above Nelaton's line. On account of the 

 backward displacement of the femora, the centre of gravity of the body 

 is advanced, arid, in order to ensure stable equilibrium, the shoulders 

 have to be thrown back. Thus the defect is always associated with 

 lordosis, and especially so when it happens to exist on both sides of 

 the body. The buttocks are prominent and the lower limbs are small. 

 (For illustration see last page.) 



THE KNEE-JOINT 



The bones forming the knee-joint are the femur, tibia, and patella ; 

 their articular surfaces are enclosed in a capsule which is greatly 

 strengthened by fibrous expansions from the crureus and vasti, and 

 from the hamstring tendons. 



The anterior ligament, or the ligamentum patellae, is the tendon of 

 insertion of the quadriceps. 



The posterior ligament descends from above the condyles of the 

 femur to the back of the head of the tibia, and derives a strong acces- 

 sion from part of the insertion of the semi-membranosus. The popli- 

 teal vessels rest upon the posterior ligament. 



The lateral ligaments, descending from the tuberosities of the 

 condyles, are placed behind the vertical axis of the knee, so as to 

 check over-extension. The inner band is wide, and descends several 

 inches down the hinder border of the tibial shaft. The outer passes to 

 the head of the fibula, over the tendon of the popliteus ; its upper end 

 may be felt beneath the skin, just in front of the tendon of the biceps, 

 the knee being slightly bent. 



The crucial ligaments cross each other obliquely, and, becoming 

 locked together, specially check inward rotation of the leg. When, 

 in an old case of knee-disease, the surgeon is able to rotate the ex- 

 tended leg inwards, he knows that these ligaments are deeply impli- 

 cated, if not destroyed. 



