THE KNEE-JOINT. 



343 



The patellar portion (Fig. 317) is situated anteriorly, and is common to both 

 condyles, although developed to a larger extent in association with the lateral condyle, 

 on which it ascends to a more proximal level than on the medial condyle. This 

 surface is trochlear, and forms a vertical groove bordered by prominent borders. 



The tibial portion of the articular surface of the femur is divided into two 

 articular areas, in relation to the distal aspects of the two condyl^s, by the wide 

 non- articular intercondyloid notch. These two surfaces are for the most part 

 parallel, but in front the medial tibial surface turns obliquely laterally as it 

 passes into continuity with the patellar trochlea, while posteriorly, under certain 

 circumstances, e.g. the squatting posture, the articular surface of the medial condyle 

 may extend to the adjoining portion of the popliteal area of the bone. 



Impression of lateral 

 meniscus 



Lateral tibial surface of 

 femur 



Fibular collateral ligament 



Cut tendon of biceps femoris 

 muscle 



Anterior proximal tibio- 

 flbular ligament 



Fibular collateral ligament 



Opening in interosseous 



membrane for anterior tibial 



vessels 



Patellar surface of femur 



Semilunar facet for patella 



Medial tibial surface of 

 fen:ur 



Posterior cruciate ligament 



Anterior cruciate ligament 



Transverse ligament 



Medial meniscus 



Tibial collateral ligament 

 Ligamentum patellae 



Medial perpendicular facet on 

 patella 



FIG. 317. DISSECTION OF THE KNEE-JOINT FROM THE FRONT : PATELLA THROWN DISTALLT. 



When the joint is in the position of extreme flexion, the patella is brought into 

 direct contact with that part of the articular surface on the medial condyle which 

 bounds the intercondyloid notch upon its medial and anterior aspects. This relation- 

 ship is indicated by the presence of a distinct semilunar facet on the cartilage in 

 that situation (Fig. 317). The articular surface of the femur may therefore be 

 regarded as presenting femoro-patellar and femoro- tibial areas. 



The patella presents on its posterior aspect a transversely elongated oval 

 articular facet and a distal rough, triangular, non-articular area. The articular 

 ; facet is divided into two principal portions by a prominent rounded vertical ridge. 

 Of these the lateral is the wider. A less pronounced and nearly vertical ridge 

 marks off an additional facet called the medial perpendicular facet, close to the 

 medial margin of the articular surface. Two faint transverse ridges cut off narrow 

 proximal and distal facets from the general articular surface without encroaching 

 on the narrow, most medial vertical facet (Goodsir) (Fig. 317). 



The head of the tibia presents on its superior aspect two condylar articular 

 , surfaces, separated from each other by a non-articular antero-posterior area, which 

 is wider anteriorly and posteriorly than in the middle, where it is elevated to form 

 a bifid eminentia intercondyloidea. 



The lateral condylar facet is slightly concavo-convex from before backwards 



