DISSECTION OF THE POSTERIOR LIMB. 



83 



the outer ; and when the patella is' dislocated, it is carried outwards 

 over the external ridge. 



THE FEMORO-TIBIAL ARTICULATION (piG. 4). 



Movements. — This is a ginglymus, or hinge joint, in which the move- 

 ments are principally ^ea;ion. and extension. In extension the bones of 

 the leg are carried forwards, but cannot be brought into a straight line 



Fig. 4. 



A. Femoro-tibial Ligaments, back view. 



1. External lateral ligament ; 2. Internal lateral ligament ; 3. Inner semilunar fibro-cartilage ; 



4. Outer semilunar fibro-cartilage, with 5, and 6, the femoral and tibial attachments (coronary 

 ligaments) of its posterior extremity ; 7. Posterior crucial ligament ; 8. Anterior crucial ligament ; 

 9. Head of fibula. 



B. Antero-posterior Vertical Section of the Femoro-tibial Articulation to show 



THE Crucial Ligaments. 



1. The posterior crucial ligament ; 2. Anterior crucial ligament ; 3. External lateral ligament ; 4, 



5, and 6, as in A. 



with the femur, the movement being arrested by tension of the lateral 

 ligaments and of the anterior crucial ligament. The contrary movement, 

 flexion, is finally arrested by tension of the posterior crucial ligament. 

 A slight degree of lateral movement and rotation can be produced when 

 the joint is flexed. 



Lateral Ligaments. — These are two strong fibrous cords, placed one 

 on each side of the joint. The external is fixed above to the higher of the 



