220 



TRE ARTICULATIONS. 



No. 1. 



No. 2. 



executed. But at the same time they also glide in an inverse direction, and 

 to a very appreciable degree, on the superior extremity of the tibia. Therefore, 

 during flexion, they pass from behind forward on this extremity, and are drawn 

 backwards during extension. 



In rotation — which may take place from within to without, or from without to 



within — the movement is produced not only 

 Fig. 142. by the pivoting of the condyles in their 



glenoid cavities, but also by a sensible dis- 

 placement of the meniscii on the tibial sur- 

 J44W, ^HM P^ ' iigk, faces. 



In the Dog and Cat, the meniscii are joined 

 together, near their anterior insprtion, by a trans- 

 verse fibrous band. There is oulyoiie patellar liga- 

 ment, aud the po.-terior lijrament shows in its sub- 

 stance, two bmall sesaitioid bones against which the 

 condyles of the femur play inwardly, and wliicli give 

 attachment, outwardly, to the originating branches 

 of the gastrocnemius muscle. There is no femoro- 

 pattllar capsule, and only one synovial membrane 

 for the whole articulation. 



In the Pig and Sheep, there is also only one 

 ligament aud one synovial capsule. 



4. TlBIO-FIBULAR ARTICULATION. 



This articulation represents a small plani- 

 form diathrosis, the movements of which are 

 very limited and ol>scure. It is formed by 

 the union of the irregular diathrodial facet 

 which occupies the internal face of the head 

 of the fibula, with the analogous facet on the 

 external superior tuberosity of the tibia. 

 Short and strong interosseous or peripheral 

 fibres envelop these facets on every side, 

 and maintain them firmly in contact. 



The fibula is also attached to the tibia : 

 " 1. Above, by two small ligamentous fasci- 

 culi crossed like the letter X, which form the 

 superior part of the great arch through which 

 pass the anterior tibial arteiy and vein (Fig. 

 142, 12). 2. In the middle, by a kind of 

 aponeurotic membrane, the width of which 

 diminishes from above to below, like that of 

 the space it fills (Fig. 142, 13). ;l Below, 

 by a ligamentous cord (Fig. 142, 14) which 

 prolongs the fibula to the external tuberosity 

 of the inferior extremity of the tibia, where 

 to the two external lateral ligaments of the 



LIGAMENTS ATTACHING THE THREE BONES 

 OF THE LEG. 



No. 1. Posterior face. No. 2. Anterior face. 

 1, Complementary fibro-cartilagiuous 

 pad of the patellar surface ; 2, external 

 patellar ligament ; 2', insertion of the 

 superficial gluteal into this ligament ; 3, 

 internal patellar ligament; 3', its upper 

 insertion transformed into a comple- 

 mentary apparatus of the patellar sur- 

 face ; 4, middle patellar ligament ; 5, 

 external meniscus of the tibia ; 6, its 

 branch of insertion into the femur cut 

 off at its origin ; 7, its posterior tibial 

 insertion ; 8, external meniscus ; 9, in- 

 sertion of the anterior crucial ligament 

 into the fossa of the tibial spine; 10, 

 tibial insertion of the posterior crucial 

 ligament; 11, inferior insertion of the 

 external femoro-tibial ligament; 12, 13, 

 14, tibio-fibular ligaments. A, Tibial 

 arch ; B, surface of insertion of the 

 popliteus muscle; C, surface of insertion 

 for the perforans muscle. 



this cord bifurcates, and is united 

 tibio-tarsal articulation " (Rigot). 



In the Ox, Sheep, and Goat, the fibula being replaced by a ligament, there is no proper 

 tibio-fibuLir articulation. 



