THE KXEE-JOIXT. 



371 



The External Semilunar Fibro-cartilage forms nearly an entire circle, covering 

 a larger portion of the articular surface than the internal one. It is grooved on 

 its outer side for the tendon 

 of the Popliteus muscle. Its 

 extremities, at their insertion, 

 are interposed between the 

 two extremities of the inter- 

 nal semilunar fibro-cartilage ; 

 the anterior extremity being 

 attached in front of the spine 

 of the tibia to the outer side 

 of, and behind, the anterior 

 crucial ligament, with which 

 it blends : the posterior ex- 

 tremity being attached behind 

 the spine of the tibia, in front 

 of the posterior extremity of 

 the internal semilunar fibro- 

 cartilage. Just before its in- 

 sertion posteriorly it gives off 

 a strong fasciculus, which 

 passes obliquely upward and 

 inward, to be inserted into 

 the inner condyle of the 

 femur, close to the attach- 

 ment of the posterior crucial 

 ligament. Occasionally a 

 small fasciculus is given off 

 which passes forward to be 

 inserted into the back part 

 of the anterior crucial lig- 

 ament. The external semi- 

 lunar fibro-cartilage gives off 

 from its anterior convex mar- 

 gin a fasciculus which forms 

 the transverse ligament. 



The Transverse Ligament 

 is a band of fibres which 

 passes transversely from the 

 anterior convex margin of the external semilunar fibro-cartilage to the anterior 

 convex margin of the internal semilunar fibro-cartilage ; its thickness varies 

 considerably in different subjects, and it is sometimes absent altogether. 



The Coronary Ligaments are merely portions of the capsular ligament, which 

 connect the circumference of each of the semilunar fibro-cartilages with the 

 margin of the head of the tibia. 



The Synovial Membrane of the knee-joint is the largest and most extensive in 

 the body. Commencing at the upper border of the patella, it forms a short cul-de- 

 8>ir beneath the Quadriceps extensor tendon of the thigh, on the lower part of the 

 front of the shaft of the femur : this communicates with a synovial bursa inter- 

 posed between the tendon and the front of the femur by an orifice of variable size. 

 On each side of the patella the synovial membrane extends beneath the aponeurosis 

 of the Vasti muscles, and more especially beneath that of the Vastus internus. 

 Below the patella it is separated from the anterior ligament by the anterior part 

 of the capsule and a considerable quantity of adipose -tissue. In this situation it 

 sends off a triangular prolongation, containing a few ligamentous fibres, which 

 extends from the anterior part of the joint below the patella to the front of the 

 intercondyloid notch. This fold has been termed the ligamentum mucosum. It 



FIG. 261. Longitudinal section through the middle of the right 

 knee-joint. (After Braune.) 



