104 THE CANCELLI OF BONES 



of "braces." The cancelli of the lumbar ver- 

 tebrae are, therefore, arranged in conformity with 

 the demand for resistance. The arrangement in 

 question is rarely obvious above the last dorsal 

 vertebra ; it is, however, present in precisely that 



FIG. 29. 



part of the column where the pressure, and, con- 

 sequently, the demand for resistance is greatest. 



II. NECK OF THE THIGHBONE 



The whole weight of the head, trunk, arms, 

 and pelvis rests on the heads of the two thigh- 

 bones, or more or less on one of them, according 

 to the attitude of the body when in a state of 

 rest. When the body is in motion they will sus- 

 tain, in addition to this, the momentum of the 

 trunk as it descends upon them in walking, run- 

 ning, jumping, etc. The heads of the bones are 



