THE ERECT POSITION. 



261 



a little in front of the atlanto-occipital joint, so that the head is largely 

 supported without muscular exertion by the stretching of the muscles 

 and ligaments at the back of the neck. These views were still further 



<D 



modified by Henke. 1 



The fact that the thigh may be rotated considerably farther backwards 

 from its position in standing, shows that the backward rotation of the pelvis 

 is not at its maximum, the ligaments therefore are not taut. Braune and 

 Fischer place the centre of rotation of the knee before the line between hip 

 and ankle-joint, and thus prove the necessity of muscular exertion to maintain 

 extension of the knee. The fact adduced as counter-evidence, namely, that 

 when the knees are straight the extensor muscles of the thigh are perfectly 

 flaccid, as tested by the patella, which can be moved from side to side without 

 resistance, is not a valid argument, as extension of the knee in the upright 



FIG. 147. The position of the centre of gravity is indicated by a dot in each of 

 the postures a, b, and c. In a and c it lies outside the body altogether. 



position can doubtless be enforced by the muscles at the back of the leg. The 

 increase of metabolism during standing upright, and its variations with varying 

 positions, offer proof of considerable muscular exertion. 



According to Braune and Fischer, who corroborate the results 

 obtained by Parow, 1 the centre of gravity plumbs in the line joining the 

 hip-joints in the Normal-stellung, and but very slightly behind it in 

 the bequeme-haltung, and very slightly in front of it in the position of 

 attention. 



These somewhat conflicting views are no doubt due to the difficulty 

 in defining what is the erect position. As a matter of fact, there are 

 many erect postures more or less comfortable, and the centre of gravity 

 may be made to plumb either in front of, above, or behind either the 

 hip, the knee, or the ankle. The erect position of the brothers Weber 



1 " Anatomic u. Mechanik der Geleuke," Leipzig u. Heidelberg, 1863, S. 215. 



2 Virchow's Arc.hiv, Bd. xxxi. 



