62 



ANIMAL MECHANICS 



The plumb-line shows the direction of the grav- 

 itation of the body falling behind the head of the 

 thighbone. Now, if it be understood that the 



O ' 



motions of the trunk are performed on the cen- 

 tre of the head of 

 the thighbone; it 

 must follow that 

 the weight of the 

 body in the direc- 

 tion of the plumb- 

 line must raise the 

 corner of the 

 haunchbone, at 



A. From this cor- 

 ner of the bone, a 

 broad and strong 

 band runs down 

 to the knee-pan, 



B, in the direction 

 of the dotted line. 

 The powerful mus- 

 cles which extend 

 the leg are at- 

 tached to the knee- 

 pan, and through 

 the ligament at C, 



operate on the bones of the leg, stretching them, 

 and preventing the flexion of the joint; but, in the 

 absence of the activity of these muscles, the band 



FIG. 15. 



