ARTICULATIONS OF THE POSTERIOR LIMBS. 163 



In Man, the head of the femur is more detached than in the domesticated animals, and 

 the cotyloid cavity, encircled by the cotyloid ligament, is deeper. The femur is united 

 to the coxa : 1, By a capsular ligament ; 2, By a^ triangular ligament, fixed above, to the 

 cotyloid ligament at the notch, and below, into the depression in the head of the femur. 

 Also, as the brothers Weber have shown, the atmospheric pressure is a powerful adjunct 

 to these means of union. 



The coxo-feinoral articulation of Man permits more extensive movements than that of 

 animals, and especially abduction and adduction, which can be carried to 90 degrees. 



3. Femoro-tibial Articulation. 1 



(Preparation. Remove the soft parts surrounding the articulation, taking care not to 

 wound the synovial membrane. To expose the crucial ligaments, make an antero- 

 posterior vertical section of the femur in such a way as to separate the condyles.) 



This is the most complicated joint in the body, and is formed by the 

 union of the femur with two of the thigh bones the tibia and patella. It 

 represents an imperfect hinge-joint. 



Articular surfaces. To form this articulation, the femur opposes its two 

 condyles to the wide, convex, and undulated facets on the superior face of 

 the lateral tuberosities of the tibia, and its articular pulley to the posterior 

 face of the patella. 



The femoral faces have already been described in detail at page 98 ; but 

 it may be repeated that the two condyles, placed side by side, are elongated 

 in an antero-posterior direction, and are separated by a non-articular notch 

 called the intercondyloid ; also, that the femoral trochlea situated in front 

 of these two condyles appears to continue the preceding notch, and that its 

 internal border is much more elevated than the external ; an arrangement 

 which explains why it is so difficult, if not impossible, for the patella to be 

 dislocated inwards. 



The tibial facets ascend on each side to the lateral faces of the tibial 

 spine. They are separated from one another by the antero-posterior groove 

 cut on the summit of that bone, and by the fossa? of insertion situated at its 

 base before and behind. The external facet, wider than the internal, is 

 devoted in part to the gliding of the originating tendon of the popliteal 

 muscle. (See page 100.) 



The patellar surface, moulded on the femoral pulley, fits it in an imper- 

 fect manner. It is bordered, outwardly, by a small fibre-cartilaginous ring, 

 which is united to the fibrous capsule of the femoro-patellar articulation 

 (Fig. 92, 1). Inwardly, it is completed by the insertion of the internal 

 patellar ligament, to be noticed immediately. . 



Interarticular meniscii (semilunar fibro-cartilages) (Figs. 91, No. 1, 2, 

 3, 4 ; and 92, 5, 6, 7, 8). By this designation is known the two fibro- 

 cartilages interposed between the condyles of the femur and the tibial facets, 

 to assure their coaptation. They are crescent shaped bodies, and present : 

 an internal, concave, thin and sharp border, embracing the tibial spice ; an 

 external, thick, and convex border ; a superior face, excavated and moulded to 

 one of the condyles ; an inferior face, nearly plane, gliding on the tibia ; and 

 two extremities terminated by ligaments, and fixed to the bones in apposition. 

 The articular surfaces are not entirely separated throughout their extent by 



1 By this name is understood the joint uniting the femur to the tibia, and that which 

 articulates it with the patella. Following the example of anthropotomists, it has not 

 been deemed necessary to describe a femoro-patellar articulation distinct from the 

 femoro-tibial, properly so called. This innovation appears to be justified by the com- 

 munity of the principal articular bands which bind these two joints, and by the reciprocal 

 dependence of their movements. 



