THE KNEE-JOINT. 



347 



Anterior cornu of 



Transverse ligament lateral meniscus 



Anterior cornu of medial 

 meniscus 



ligament is tense in the position of extension, and therefore it assists in maintaining 

 the erect attitude. 



The ligamentum cruciatum posterius (Figs. 31*7, 319, and 320) is somewhat shorter 

 than the preceding. It is attached distally to the posterior part of the depressed 

 surface behind the intercondyloid eminence of the tibia and close to the popliteal 

 notch. Its fibres pass obliquely proximally, forwards, and medially, to be inserted 

 into the lateral non-articular surface of the medial condyle, far forwards towards 

 the anterior margin of the intercondyloid notch. It is rendered tense in the 

 position of flexion. 



The semilunar menisci are two in number a medial and a lateral placed 

 horizontally between the articular surfaces of the femur and tibia. In general 

 outline they correspond to the circumferential portions of the tibial facets upon 

 which they rest. Each has a thick, convex, fixed border in relation to the periphery 

 of the joint, and a thin, concave, free border directed towards the interior of the 

 joint. Neither of them is sufficiently large to cover the whole of the tibial articular 

 surface upon 

 which it rests. 

 The proximal 

 and distal sur- 

 faces of each 

 meniscus are 

 smooth and 

 free, and each 

 terminates in 

 an anterior and 

 a posterior 

 fibrous horn or 

 cornu. 



Meniscus 

 Me di alls. 

 The medial 

 meniscus (O.T. 

 internal semi- 

 lunar fibro-carti- 

 lage) (Figs. 319 

 and 320) forms 



very nearly a semicircle. It is attached by its anterior horn to the non-articular 

 surface on the head of the tibia, in front of the tibial attachment of the anterior 

 cruciate ligament, and by its posterior horn to the non-articular surface imme- 

 diately in front of the tibial attachment of the posterior cruciate ligament. The 

 deep or posterior part of the tibial collateral ligament is attached to its periphery. 



Meniscus Lateralis. The lateral meniscus (O.T. external semilunar fibro- 

 cartilage) (Figs. 319 and 320) is attached by its anterior horn to the non-articular 

 surface of the tibia in front of the intercondyloid eminence, where it is placed to 

 the lateral side, and partly under cover of the tibial end of the anterior cruciate 

 ligament. By its posterior horn it is attached to the interval between the two 

 tubercles which surmount the intercondyloid eminence, i.e. in front of the attach- 

 ment of the posterior horn of the meniscus medialis. This fibro-cartilage, with its 

 two horns, therefore forms almost a complete circle. Posteriorly it is attached by 

 its periphery to the posterior ligament, but on the lateral side it is separated from 

 the fibular collateral ligament by the tendon of the popliteus muscle, and on this 

 aspect its periphery is free. 



The two horns of the lateral meniscus are embraced by the -two horns of the 

 medial meniscus, and, while the anterior cruciate ligament has its tibial attachment 

 almost between the anterior horns of the two menisci, the tibial attachment of the 

 posterior cruciate ligament is situated behind the posterior horns of the two menisci. 



Both menisci possess certain accessory attachments. Thus the lateral meniscus 

 sends a large bundle of fibres from its convex posterior border to augment the 

 posterior aspect of the posterior cruciate ligament by which these fibres are 



Medial 

 meniscus 



Posterior cornu 

 of medial 

 meniscus 



Posterior cornu of 



lateral meniscus 



Fasciculus from lateral meniscus 

 to posterior cruciate ligament 



Posterior cruciate ligament 

 FIG. 320. PROXIMAL END OF TIBIA WITH MENISCI AND ATTACHED PORTIONS OP 

 CRUCIATE LIGAMENTS. 



