456 



THE INFERIOR EXTREMITY 



thin away to their free central margins. The peripheral border 

 of the medial meniscus is firmly adherent to the tibial collateral 

 ligament, but the fibular collateral ligament is separated from 

 the lateral meniscus by the popliteus tendon, its synovial bursa, 

 and the lateral inferior genicular artery. On this account, 

 although both menisci are permitted a certain amount of move- 

 ment to enable them to accommodate themselves to the articular 

 surfaces in different positions of the joint, the medial meniscus 

 is the less freely movable of the two. Further, since the 



FIG. 133. The Menisci and their Attachments. 



1. Transverse ligament. 



2. Anterior cornu of medial meniscus. 



3. Anterior cruciate ligament. 



4. Medial tubercle of intercondyloid emin- 



ence of tibia. 



5. Medial meniscus. 



6. Posterior cornu of medial meniscus. 



7. Posterior cruciate ligament. 



8. Fasciculus from lateral meniscus to 



posterior cruciate ligament. 



9. Posterior cornu of lateral meniscus. 



10. Lateral tubercle of intercondyloid 



eminence of tibia. 



11. Lateral meniscus. 



12. Anterior cornu of lateral meniscus. 



extremities of the medial meniscus are more widely separated 

 from one another than those of the lateral meniscus, the latter 

 enjoys greater freedom. 



Injuries of the menisci occur in forcible rotation of the flexed 

 or semi-flexed knee. The tibia may be rotated on the femur 

 when the latter is fixed, or the femur may be rotated on the 

 tibia when the tibia is fixed. Statistics show that the medial 

 meniscus suffers injury much more frequently than does the 

 lateral meniscus, and it is probable that the comparative 

 immunity of the lateral meniscus is due to its greater range of 

 movement. 



When the tibia is fixed and the femur is suddenly and 



