THE BONES. 31 



steadied or swung in the cavity by a strong ligament running 

 up from the base of the cavity to the summit of the head, 

 which holds it in place, and prevents jars and dislocations. 

 Some of the muscles, also, which move the thigh bone pass 

 over this joint, and help to keep it in place. 



28. The Knee. The lower end of the thigh bone is so 

 large as really to suggest the idea of a war-club. Indeed, 

 some savage tribes use the thigh bone as a weapon of war. 



FIG. 10. The Mechanism of the Hip Joint. 



The large end of this bone rests upon the broad, flat end of 

 the shin bone, forming the knee joint. This hinge joint is 

 protected in front by a flat three-sided bone, the patella, or 

 knee-pan. Although the knee is greatly exposed, the broad 

 joint surface, with its strong ligaments and tendons, enables 

 it to resist violence, and dislocation does not frequently 

 happen. Indeed, fracture of one o the bones is more likely 

 to occur. 



