INTRA-CAPSULAR LIGAMENTS OF KNEE. 



639 



Fig. 220. 



of the condyles of the femur, but are flattened below. Inserted into the 

 tibia at their extremities, they are coarsely fibrous at their attachment to 

 the bone, like the crucial ligaments ; and they become cartilaginous only 

 where they lie between the articular surfaces. The synovial membrane is 

 reflected over them. 



The internal cartilage (a) is ovoid in form, and is a segment of a larger 

 circle than the external. In front it is attached by a pointed part to the 

 anterior margin of the head of the tibia, 

 in front of the anterior crucial liga- 

 ment. At the back, where it is much 

 wider, it is fixed to the inner lip of the 

 hollow behind the spine of the tibia, 

 between the attachment of the other 

 cartilage and the posterior crucial liga- 

 ment. 



The external cartilage (b) is nearly 

 circular in form, and is connected to 

 the bone within the points of attach- 

 ment of its fellow. Its anterior part is 

 fixed in front of the spine of the tibia, 

 close to the outer articular surface, and 

 opposite the anterior crucial ligament, 

 which it touches ; and its posterior 

 extremity is inserted behind and be- 

 tween the two osseous points of the 

 spine. This fibro-cartilage is less 

 closely united to the capsule than the 

 internal, for the fore part is in the cen- 

 tre of the joint, and the tendon of the 

 popliteus muscle separates it behind 

 from that membrane. 



The outer fibro-cartilage is provided with two accessory bands, one at 

 the fore part, the other behind. 



The anterior or transverse ligament (c) is a narrow band of fibres be- 

 tween the semilunar cartilages at the front of the joint. Sometimes it is 

 scarcely perceptible. 



The posterior or ascending band (d), thicker and stronger than the 

 other, springs from the back of the outer fibro-cartilage, arid is inserted 

 into the femur as a single band (fig. 219, d) in front of the posterior 

 crucial, or as two bands one being before, and the other behind that 

 ligament. 



Use. The fibro-cartilages deepen the sockets of the tibia for the recep- 

 tion of the condyles of the femur, and fill the interval between the articu- 

 lar surfaces of the bones at the circumference of the joint ; they moderate 

 the injurious effect of pressure of the one bone on the other ; and cause 

 the force of shocks to be diminished in transmission. 



In flexion and extension they move forwards and backwards with the 

 tibia. During flexion they recede somewhat from the fore part of the 

 joint, and surround the condyles of the femur; but in extension they are 

 flattened out on the surface of the tibia. Of the two cartilages the ex- 

 ternal moves the most in consequence of its ends being less attached to 

 the capsule. 



VIEW OF THE HEAD OP THE TIBIA WITH 

 THE FlBRO CARTILAGES ATTACHED : THE 



CRUCIAL LIGAMENTS HAVE BEEN CUT 

 THROUGH. 



a. Inner, and b, outer semilunar fibro-car- 

 tilage. 



c. Transverse, and d, ascending or poste- 

 rior band (cat) of the external carti- 

 lage. 



e. Posterior, and /, anterior crucial liga- 

 ment. 



