The Framework of the Body 



56, The Femur, or Thigh Bone. 



The longest and strongest of all the 

 bones is the femur, or thigh bone. Its 

 upper end has a rounded head which 

 fits into the acetabulum, or the deep 

 cup-like cavity of the hip bone, form- 

 ing a perfect ball-and-socket joint. 

 The rounded head fits so accurately 

 into its socket that it may be retained 

 by atmospheric pressure alone. 



The shaft of the femur is strong, 

 and is ridged and roughened in places 

 for the attachment of the muscles. 

 Its lower end is broad and irregularly 

 shaped, having two prominences 

 called condyles, the whole fitted for 

 forming a hinge joint with the upper 

 end of the shin bone. 

 X 57. The Bones of the Leg. The 

 leg, like the forearm, consists of two 

 bones. The tibia, or shin bone, is 

 the long, three-sided bone forming 

 the front of the leg. The sharp 

 edge of the bone is easily felt just 

 under the skin. It articulates with 

 the lower end of the femur. 



The fibula is a long, slender bone 

 on the outer side of the leg, and 

 is firmly fixed to the tibia at each 

 end. Its lower end forms the 

 outer projection of the ankle. 



In front of the knee joint, im- 

 bedded in a thick, strong tendon, 



39 



FIG. 24. Right Femur, or 

 Thigh Bone. 



