216 THE ARTICULATIONS. 



ligament at tlie notch, ami below, into the depression in the head of the femur. Also, as the 

 brothers Weber have .--hown, the atmospheric pressure is a powerful adjunct to these means 

 of union. 



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

 animiils, and especially abduction and addustioii, which cau be canied to 90 degrees. 



3. Femoro-tibial Articulation (Fig. 141).^ 



Preparation. — Kemove the soft parts surrounding the articulation, taking cure not to wound 

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

 section of the femur in each 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 con- 

 dyles 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 fares have already been described in detail (p. 137) ; 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 inter- 

 condyloid ; 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 impossiWe, for the patella to be dislocated inwards. 



The tibiaJ 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 fossae 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. 



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

 manner. It is bordered, outwardly, by a small fibro-cartilaginous ring, which is 

 united to the fibrous capsule of the femoro-patellar ariiculation (Fig. 141, 1). 

 Inwardly, it is completed by the insertion of the internal patellar ligament, to be 

 noticed immediately. 



Tnterarticular meniscii {semilunar fihro-cartilages) (Figs. 141, a 1, 2, 3, 4 ; 

 and 142, 5, 6, 7, 8). — By this designation are 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 spine ; 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 liga- 

 ments, and fixed to the bones in apposition. The articular surfaces are not entirely 

 separated throughout their extent by these complementary meniscii, for the tibial 

 spine rubs directly against the inner sides of the femoral condyles. The internal 

 semilunar fihro-cartiku/e, the widest and thickest, is inserted by its anterior 

 extremity into one of the excavations situated in front of the spine ; its posterior 



' By this name is understoo 1 the joint uniting the femur to the tibia, and that wliicli 

 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 femuro-tibial, 

 properly so called. This innovation appears to be justified by tlie community of the principal 

 articular bands which bind these two joints, and by the reciprocal dependence of their 

 movements. 



