THE PATELLA. 



137 



joint. The inner epicondyle is the larger and most 

 marked. 



The shaft of the femur is a cylinder of compact or 

 dense bone ; the pvtrpnniHps RVP h"^y n containing can- 



cellated tissue covered by a thick shell of dense bone. 

 The structure of the femur is sucH as to give the greatest 

 longitudinal resistance for the quantity of bone it con- 

 tains. The cancellated contents of the upper extremity 

 are disposed in a series of curved plates, thus increasing 

 the elasticity and carrying power of the head and neck 

 of the bone. 



The femur develops by five centres, one for the 

 shaft, one for the condyles, one for the head, and one for 

 each of the trochanters. 



THE PATELLA. 



The patella is situated at the front of the knee-joint, 

 and is the fulcrum over which the common extensor 



(Anterior surface.) (Posterior surface.) 



FIG. 65. THE RIGHT PATELLA. 



muscle-oiLthe_thigh acts. It is a sesamoid bone which 

 remains cartilaginous up to the third or fourth* year, the 

 earliest indication of a centre of ossification being seldom 

 met with before the twentieth month. It is shaped some^ 

 wh^. likp a hnrsp-nhestnnj^and presents an anterior and 

 posterior surface, an uppeT broad portion, the base. 

 and a lower, somewtiaFpomted, called theapex. The 



