THE STIFLE JOINT 



237 



practically of the synovial layer only. It is much stronger posteriorly: here it 

 is reinforced by what might be regarded as a posterior ligament. This is a 

 strong, flat band which arises from the femur just lateral to the origin of the medial 

 head of the gastrocnemius, and extends down to the posterior border of the medial 

 condyle of the tibia; it is wider below than above. There are two synovial sacs, 

 corresponding to the double nature of the articular surfaces; they do not usually 

 communicate, and each is partially divided into an upper and a lower compartment 

 by the meniscus. The medial sac pouches upward about half an inch over the con- 



Lateral condyle of 

 femur 



Lateral femoro- — jMi*] 

 tibial ligament ii'^lW 



Stump of pop- 

 liteus tendon 

 Lateral meniscus -^ 



Lateral condyle of 

 tibia 



Head of fibula 



Interosseous space 



ilcdinl fenioro- 

 \\\\V\ tibial liqament 



i'!Li— Medud condyle of 

 femur 



Medial memscus 



J — Medial condyle of 

 tibia 



Fi<5. 249. Left Stifle Joint of Horse; Postebiob View. The Capsule is Removed. 



1, Femoral ligament of lateral meniscus; 2, posterior ligament of lateral meniscus; 3, anterior cruciate ligament; 4, 



posterior cruciate ligament. 



dyle of the femur. The lateral sac invests the tendon of origin of the popliteus 

 muscle, and also pouches downward about three inches (ca. 7.5 cm.) beneath the 

 peroneus tertius and extensor longus muscles. As stated above, the lateral sac 

 sometimes communicates with the femoro-patellar joint cavity, and the medial 

 sac usually does so in the adult. 



Ligaments.— There are four of these— two collateral and two cruciate. 



The medial ligament (Lig. collaterale tibiale) is attached above to the prom- 

 inent medial epicondyle of the femur, and below to a rough area below the margin 

 of the medial condyle of the tibia. 



