412 



THE INFERIOR EXTREMITY 



for the patella, and two condylar surfaces which move on the menisci and 

 tibia. The trochlea is separated from the surface of the lateral condyle by a 

 faintly marked groove, which takes a slightly curved course, from the lateral 

 border of the distal end of the femur, medially and posteriorly to the fore 

 part of the intercondylar fossa. At each extremity this groove widens out 

 into a distinct depression. In full extension the lateral depression rests 

 upon the anterior part of the lateral meniscus, whilst the medial depres- 

 sion rests against the anterior border of the lateral tubercle of the inter- 

 condyloid eminence of the tibia (Bruce Young). The line of demarcation 

 between the trochlea and the distal surface of the medial condyle of the 

 femur is not so distinct. Close to the medial margin of the bone there is a 



Popliteal artery 



M. semitendinosus 

 M. semimembranosus 

 Deep fascia 



Middle genicular arte 



Popliteal fascia 



Anterior cruciate 



ligament 



Oblique popliteal/ 

 ligament 



Popliteal artery 



Popliteal vei 

 Tibial nerve 



Plantaris tendon 

 M. popliteus 



M. gastrocnemius 



Supra-patellar 



U~7*"'ir "ursa, continuous 

 ' 



with cavity of joint 



4- Quadriceps tendon 



jT-T-TT Patella 



t'' y/3 Subcutaneous 



* //'T prepatellar bursa 

 Wl Ip^'ity f knee 

 TIT-IT i 'joint 



/ // Infra-patellar pad 

 --J- /of fat 



-j Patellar synovial fold 

 -/ Apices of menisci 



- Deep infra-patellar bursa 



-Subcutaneous infra- 

 patellar bursa 



Tuberosity of tibia 

 Tibia 



FIG. 181. Sagittal Section of the Knee Joint. 



depression which, in full extension, rests upon part of the anterior horn of 

 the medial meniscus (Bruce Young) : but lateral to this the trochlear 

 surface is prolonged posteriorly for a certain distance along the anterior 

 and medial margin of the intercondylar fossa. A portion of the medial 

 condyle is thus included in the trochlear surface, viz., the portion skirting 

 the medial border of the anterior part of the intercondylar fossa, and this 

 is termed the " crescentic facet " of the medial condyle. 



The posterior surface of the patella may next be examined (Fig. 178), and 

 its movements in connection with flexion and extension of the knee joint 

 studied. A high vertical ridge divides the posterior surface into a large 

 lateral and a smaller medial area. Each of these is still further subdivided 

 by faint ridges on the cartilage which coats the surface. A faint line upon 

 the medial area of the patella descends in a vertical direction so as to mark 

 off a narrow strip close to the medial border of the bone. This strip is 



