THE KNEE JOINT 



35 



patella 1 is inserted into the tendon which runs from the 

 thigh muscle over the front of the knee to the tibia. 

 The patella is a flattened rounded bone, which protects 



Femur 



Tendon of muscle 

 extending leg 

 Synovia I sac (distended) 

 Patella 

 Bursa 



Tendon of pate 



f"Dsterior cross 



ligament of knee- 

 Anterior cross 



ligament of knee 



Articular cartilage - 



Bursa 



FIG. 28. Cross section of knee, showing the various structures which make up 

 the knee joint (somewhat diagrammatic). 



the tendon and to some extent the knee joint also. It 

 is, however, itself subject to rather frequent injury on 

 account of its exposed position. 



'The patella is really a specialized part of the tendon itself, 

 developed for the purpose of making the tendon better able to 

 withstand contact with objects. Similar examples of the develop- 

 ment of bone in tendons is found in other places where tendons 

 are liable to injury, as under the second joint of the big toe. 



