THE STIFLE JOINT loi 



Between the two lateral membranes the anterior and posterior crucial 

 ligaments are placed. These two membranes line the posterior common 

 ligament. 



In front of the condyles and the intercondyloid notch the lateral 

 synovial membranes are in close relationship to that of the femoro- 

 patellar joint, and occasionally they communicate with the latter. There 

 is also at times a direct communication between the two lateral synovial 

 cavities, but according to Lesbre and quoted by Chauveau, such com- 

 munication is of rare occurrence. 



The two principal movements of the stifle joint are flexion and 

 extension, but it is also capable of slight rotation. During flexion and 

 extension the femoral condyles glide in the cavities on the superior 

 aspect of the cartilages. Whilst the joint is being flexed there is a 

 slight forward movement of the cartilages on the tibial facets, and they 

 move in the opposite direction during the process of extension. The 

 cartilages are also capable of very slight side to side displacement during 

 rotation of the joint. 



When the femoro-tibial joint is completely extended, the patella is 

 placed on the upper part of the trochlea and the straight patellar liga- 

 ments are made very tense. The latter are relaxed and the patella 

 descends along the trochlea during flexion of the stifle. 



Tendons which play over the Joint 



The common tendon of the quadriceps extensor cruris muscle has 

 already been referred to as being inserted into the straight patellar 

 ligaments. Arising from the lower and more anterior of the two pits, 

 on the excentric side of the external condyle, is the tendon of origin of 

 the popliteus muscle. This tendon is partially invested by the external 

 lateral synovial membrane and it plays over the outer semilunar disc, 

 so that it is in intimate relationship to the joint. The belly of the 

 popliteus lies on the posterior surface of the posterior common ligament. 



