THE JOINTS. 



one, extends from the internal tuberosity of the femur to 

 the internal tuberosity of the tibia. The anterior and cap- 

 sular ligaments must be cut in order 

 to see the crucial ligaments, which 

 are short, and cross each other in 

 the region of the intercondylar notch. 

 The posterior crucial extends from 

 the caudal margin of the head of 

 the tibia to the mediocranial angle 

 of the intercondyloid notch of the 

 femur. The anterior crucial extends 

 from the summit of the tibia to the 

 caudolateral angle of the intercondy- 

 loid notch. The tibiofibular ligament 

 is very short, extending from the 

 head of the fibula to the outer tu- 

 berosity of the tibia. In addition to 

 these ligaments, there are four 

 bands uniting the menisci to the 

 bones. The menisci or semilunar 

 cartilages are two biconcave car- 

 tilaginous plates, about one milli- 

 meter thick, interposed between the 

 condyles of the femur and tibia. 



The synovial membrane is a very 

 thin transparent sheet lying within 

 the capsular sheath of the joint. It 

 secretes the white glairy synovia for 

 lubricating the joint. The synovial 

 fluid and membrane may be demon- 

 strated by cutting open a fresh joint 

 obtained from the butcher-shop (Fig. 44). 



All other freely movable joints are similar in structure to 

 the knee-joint, but have no menisci and fewer ligaments. 



FIG. 46. CAUDAL ASPECT 

 OF KNEE-JOINT WITH 

 CAPSULAR LIGAMENT 

 CUT. 



ac, Anterior crucial liga- 

 ment ; ar, articular sur- 

 face of condyle of 

 tibia ; en, condyle of 

 femur ; cp, capsular 

 ligament cut along the 

 line lg and reflected 

 proximad ; ex, external 

 lateral ligament; fb, 

 fibula ; fm, femur ; in, 

 internal lateral liga- 

 ment; lg, cut edge of 

 capsular ligament; pc, 

 posterior crucial liga- 

 ment ; pi, posterior ex- 

 ternal ligament of the 

 meniscus ; sm, medial 

 or internal meniscus; 

 sme, lateral or exter- 

 nal meniscus ; tf, tibio- 

 fibular ligament ; tb, 

 tibia. 



