534 A MANUAL OF ANATOMY 



outgrowth of the condyles of the femur. (2) According to Bland-Sutton, 

 they are modifications of muscles, but there are no certain facts as to which 

 muscles they originally belonged. 



The semilunar flbro-cartilages are two in number — internal 

 and external. They are lunated plates, of very firm consist- 

 ence, which are placed upon the peripheral parts of the condylar 

 articular surfaces of the tibia so as to deepen them for the 

 reception of the condyles of the femur. They also serve as 

 cushions, which mitigate pressure and diminish shock. Each 

 presents two surfaces, superior and inferior ; two borders, outer 

 and inner ; and two extremities or cornua, anterior and posterior. 

 The superior surface is slightly concave to adapt itself to a femoral 

 condyle, being sloped from the outer to the inner border. The 

 inferior surface is flat, and rests upon a condylar surface of the 

 tibia at its circumference. Both these surfaces are covered by the 

 synovial membrane of the joint. The outer border is convex and 

 thick, and it is attached to the margin of the corresponding tuber- 

 osity of the tibia by fibres which are really a part of the capsular 

 ligament, but which have received the name of coronary ligament 

 (one for each fibro-cartilage). The external semilunar fibro- 

 cartilage is more loosely attached in this manner than the internal. 

 Partly on this account, and partly by reason of the close proximity 

 of its two cornua, the external fibro-cartilage is more movable than 

 the internal. The inner border of each fibro-cartilage is very thin, 

 sharp, and concave. It is quite free, and covered by the synovial 

 membrane. 



The extremities or cornua are thin fibrous bands, which have 

 the following attachments : the anterior cornu of the internal 

 semilunar fibro-cartilage is attached to the rough depression in 

 front of the spine of the tibia at its anterior and inner part ; or, to 

 put it in another way, it is attached to the upper surface of the 

 head of the tibia in front, and to the outer side, of the internal 

 condylar surface. It has the anterior crucial ligament directly 

 behind it. The posterior cornu is attached to the inner part of the 

 rough depression behind the spine of the tibia, where it has the 

 posterior crucial ligament behind it. The internal semilunar fibro- 

 cartilage is semicircular, and may be likened to the capital letter C, 

 its cornua being wide apart, and embracing between them the 

 cornua of the external semilunar fibro-cartilage. It is intimately 

 connected with the internal lateral ligament. 



The anterior cornu of the external semilunar fibro-cartilage is 

 attached to the head of the tibia immediately in front of the outer | 

 tubercle of the spine, where it is placed on the outer side of andj 

 behind the anterior crucial ligament. The posterior cornu isj 

 attached to the rough depression between the two tubercles of thej 

 spine, and also to a depression immediately behind the outer jj 

 tubercle. The external semilunar fibro-cartilage is almost circular,,; 

 thus O, its cornua being very close together, and being embraced; 

 by the cornua of the internal semilunar fibro-cartilage. The pos-;^ 



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