404 



HUMAN ANATOMY. 



The lower surfaces of the disks adapt themselves to the top of the tibia, the outer 

 cartilage concealing the convexity at the back of the tuberosity. The upper surfaces 

 form cups to receive the femoral condyles. At the sides of the spine, where the 

 cartilages are wanting, the cups are completed by the upward slope of the tuber- 

 osities. 



The coronary ligaments (Fig. 420) are parts of the capsule connectmg the 

 periphery of the semilunar cartilages with the tibia. They are of litde strength and 

 allow more or less motion. Those of the external cartilage are more than two cen- 

 timetres long at the front and 1.3 centimetres at the back, while those of the internal 

 are from four to five millimetres. Thus the external cartilage can move very freely 

 on the tibia, both from the length of these ligaments and from the approximation of 

 its horns, while the internal can move but little. This has an important influence 



Fig. 419. 



Shaft of femur 



Patella 



Alar ligament 



Internal semilunar cartilage 



Posterior crucial ligament 



Bursa of tendon 

 of semimembranosus 



Bursa beneath extensot 

 tendon 



Capsule 



Alar ligament 



Anterior crucial ligament 



External semilunar cartilaee 

 Tendon of popliteus 



Capsule reflected 



Anterior wall of right knee-joint seen from behind, the lower end of the femur having been removed. 



on the mechanics of the joint. The popliteus muscle is attached to the outer, 

 which is significant in the same connection. 



The transverse ligament ' (Fig. 420) is a band, usually ill-defined and often 

 quite wanting, which connects the cartilages at the front of the knee, running from 

 the convexity of the outer to near the anterior cornu of the inner and sometimes 

 into it. It is closely attached to the capsule in front. 



The crucial ligaments ^ (Figs. 419, 420) are two broad, thick bands, the strong- 

 est in the joint. The anterior arises from the depression in front of the spine of the 

 tibia, close to the external semilunar cartilage, and runs upward, backward, and 

 outward to the back of the inner side of the outer condyle. The posterior, the 

 stronger, arises from the back of the groove at the posterior aspect of the top of the 

 bone, and from its outer border, leaving the floor of the groove and the transverse 

 piece of the spine of the tibia free and covered by synovial membrane. It is also 

 closely connected with the external semilunar cartilage. It runs forward, upward, 

 and a little inward to the front of the outer side of the inner condyle and of the 



* Lift transversnm (ena. ^ Llgamenta cmciota genu. 



