THE KNEE-JOINT. 



153 



position : flexion is limited only by the contact of the neck of the femur with the 

 acetabulum. The round ligament is put upon the stretch when the thigh is partially 

 flexed and adducted; it therefore resists dislocation upwards and backwards on 

 the dorsum ilii, which is, notwithstanding its presence, the most frequent kind of 

 displacement. The round ligament is also put upon the stretch in the position of 

 flexion and external rotation. 



THE KNEE-JOINT. 



The articular surfaces of this .complicated joint are the condyles of the 

 femur and tibia, with fibro- cartilages interposed, the articulating surface of 

 the patella, and the patellar surface of the femur. The action is mainly that 

 of a hinge-joint. The joint is strengthened superficially by fibrous coverings 



Fig. 140. 



Fig. 140, A. RIGHT KNEE-JOINT, FROM THE INSIDE AND ANTERIORLY. J 



1, tendon of the rectus muscle near its insertion into the patella ; 2, insertion of the 

 vastus internus into the rectus tendon and side of the patella ; 3, ligamentum patellae 

 descending to the anterior tuberosity of the tibia ; 4, capsular fibres forming a lateral 

 ligament of the patella prolonged in part from the insertion of the vastus internus down- 

 wards towards the inner tuberosity of the tibia ; 5, internal lateral ligament of the knee- 

 joiut seen spreading on the internal semilunar cartilage ; 6, tendon of the semimembranosus 

 muscle (after Arnold). 



Fig. 140, B. KNEE-JOINT FROM BEHIND. 



1, insertion of the tendon of adductor magnus ; 2, origin of the inner head of the 

 gastrocnemius muscle ; 3, outer head of the same ; 4, cord-like external lateral ligament ; 

 5, tendon of the popliteus muscle : a ligament descending from behind the outer condyle 

 of the femur is seen attached to this tendon below, and another descending from the 

 tendon is attached to the head of the fibula, constituting the short external lateral liga- 

 ment ; 6, part of internal lateral ligament ; 7, tendon of the semimembranosus muscle ; 

 8, posterior ligament of Winslow, spreading outwards from the tendon ; 9, expansion of 

 the popliteal fascia downwards from the same, represented as cut short; 10, on the head 

 of fibula, marks the posterior superior tibio-fibular ligament; 11, upper part of the 

 interosseous ligament, with the foramen above it for the anterior tibial artery. 



