PALM AND SOLE STUDIES. 1 67 



side of the foot, quite above the tread area, where in man it may 

 still be found greatly reduced in size and importance, but occa- 

 sionally quite evident (Fig. 23). 



Difficult to even locate at first, one soon becomes accustomed 

 to picking out the thenar pad on almost any foot, and in cases 

 where it is really prominent, and when seen in the right light, it 

 forms a conspicuous object. The friction-ridges crossing this 

 eminence almost always exhibit some disturbance of their other- 

 wise even course across the foot, and occasionally show a distant 

 loop with a triradius (Fig. 21). As is to be expected, too, the 

 best developed patterns are likely to occur on the most conspicu- 

 ous pads, the atavistic tendency manifesting itself in these two 

 ways at the same time. The last vestige of the thenar pattern 

 is indicated upon a flat surface, without trace of a pad, by a 

 slight disturbance of the friction-ridges in this place (Figs. 13, 

 17, 24, and 25). 



Miss Whipple, in her fundamental work upon the whole subject 

 of epidermic ridges, has considered the causes of the degeneration 

 of the thenar pad of man and finds the principal one in the estab- 

 lishment of the long arch, spanning the distance between the 

 ball and the heel. The thenar pad, and, as she states, the 

 hypothenar also, are both situated directly beneath the center 

 of the long arch, and their reduction thus becomes a matter of 

 necessity. 1 Schlaginhaufen 2 gives several prints of the thenar 

 pattern, without definitely designating it as such, and was quite 

 right in stating that he was the first to carefully investigate this 

 pattern. In its best developed form this thenar pattern, as 

 thus far recorded, seems to consist of a simple loop with a single 

 triradius (Fig. 21), or occasionally, two loops, with the triradius 

 between them. 3 



Light is shed upon the question of the hypothenar pattern by 

 the interpretation of the long-extended human sole as formed from 

 the hypothenar region, since, if this be true, the pattern, or 

 elements of it, may thus be looked for on any part of this area. 

 This would determine at once as hypothenar, not only the narrow 

 loop found quite commonly upon the fibular edge of the foot, a 



1 Cf. Miss Whipple, 1904, p. 292, Fig. 19. 



2 1905, pp. 107-109, Figs. 182-184. 



3 Schlaginhaufen, loc. cit., Fig. 183, i. 



