168 MECHANISM AND FUNCTIONS OF THE JOINTS. 



Ligamenta patella are composed of four strong cords, which 

 descend over the condyles of the os femoris, and are insert- 

 ed into the tubercle of the tibia. The external one passes 

 upon the outer and anterior part of the external condyle ; the 

 internal, upon the inward part of the internal condyle ; and 

 the middle one, between them ; they approach each other in 

 their descent. Concealed by the external one is the fourth 

 ligament of the patella ; it runs to the outward part of the 

 tibia. 



The patella, with its articulatory surface of the condyles 

 in front, forms a joint of its own, perfectly distinct from that 

 between the tibia and os femoris. 



Its capsular ligament is fixed to its surrounding border. 



I?iternal lateral ligament descends from the internal con- 

 dyle to the inner and upper part of the tibia. 



External lateral ligament — stronger than the internal — 

 runs from the external condyle to the upper end of the fibula. 



Crucial ligaments, short and strong, and deeply buried 

 within the joint, run from the space within the condyles to 

 the tibia. 



The synovial membrane, after having lined the capsule, is 

 reflected upon the cartilages and ligaments included within it. 



Hock joint has four lateral ligaments, two on each side, 

 called internal and external. 



Capsular ligament includes the lower end of the tibia, and 

 the pully-like part of the astragulus ; to both of which, and 

 the lateral ligaments, and to the os calcis, it is firmly attached. 



The 05 calcis forms a joint with the os cuboides, and the 

 ossa cuneiforme are also a joint, and the middle and small bones 

 make joints with the cuboid above, and the metatarsi below ; 

 hence, there are six articulations in addition to what we com- 

 monly understand by the hock joint, that between the tibia 

 and astragulus. 



