SUPERIOR FACE OF THE BODY. 



135 



WHOLE. The pelvis, as a whole, may incline more or less towards 

 the horizontal or the vertical line. 



Although these misplacements are more rare and less marked than 

 those of the individual bones, such general misplacements are never- 

 theless sometimes observed. 



The ilio-ischial angle in such cases is ordinarily more closed than 

 is normal, owing to a diminished obliquity of the ischium^ -The for- 

 ward and backward rotation of the coxae can thus be accomplished 

 without perceptibly modifying the direction of the floor of the pelvic 

 cavity. 



This rotation, in one direction or in the other, modifies the obliquity 

 of the croup (Fig. 41) more than the partial variations to which we 

 have alluded. 



When the coxce are rotated backward, A'OB', the combined result, a 

 straightening of the ilium and lower- 

 ing of the ischium, is both favor- 

 able and unfavorable. Velocity is 

 diminished and force increased. The 

 croup and loins are strengthened, 

 and the power for traction increased. 

 The femoral impulsion is reduced 

 because it is applied too vertically. 

 This conformation, when it is exag- 

 gerated, disturbs the axis of the 

 members by placing the latter under 

 the trunk ; it is altogether incom- 

 patible with great speed, but is not 

 detrimental to slow work which re- 

 quires great force. 



An inverse displacement, A" OB", 

 naturally means opposite results. 

 The muscles are longer, their play is 



augmented, the transmission of the motor impulse is more horizontal, 

 but the regions above are weakened. 



As soon as the horizontal direction passes beyond certain limits, 

 the hind limbs tend to rest posterior to their vertical axis, and the 

 extension and flexion of the femur become insufficient. There is a 

 tendency towards a disposition analogous to that in the ox, whose 

 loins are weak, not only on account of their great length, but also in 

 consequence of the conformation of the croup, whose inclination is but 

 faintly marked. 



FIG. 41. 



