HAND AND FOOT COMPARED. 83 



fixed to the sides of the sacrum. The socket of the scapula, 

 into which the head of the humerus fits, is very shallow 

 and allows a far greater range of movement than is per- 

 mitted by the deeper socket on the pelvis, into which the 

 head of the femur fits. Further, if we hold the right 

 humerus tightly in the left hand and do not allow it to 

 move, we can still move the forearm bones so as to turn 

 the palm of the hand either up or down: no such move- 

 ment is possible between the tibia and fibula. Finally, in 

 the foot the bones are much less movable than in the 

 hand, and are arranged so as make a springy arch (Fig. 35) 

 which bears behind on the calcaneum, Ca, and in front on 

 the distal ends of the metatarsal bones, Os; over the crown 

 of the arch, at Ta, is the surface with which the leg-bones 



Sfhl 



M5 



FIG. 35. The bones of the foot. Ca, calcaneum, or os calcis; Ta, articular 

 surface for tibia on the astragalus; N, scaphoid bone; CI, CII, first and second 

 cuneiform bones; Cb, cuboid bone; Ml, metatarsal bone of great toe. 



articulate and on which the weight of the Body bears in 



standing. 



The toes, too, are far less movable than the fingers, and 

 this difference is especially well marked between the great 

 toe and the thumb. The latter can be made to meet each 

 of the finger-tips and so the hand can seize and manipulate 

 very small objects, while this power of opposing the first 

 digit to the rest is nearly absent in the foot of civilized 

 man. In children, however, who have never worn boots, 

 and in savages, the great toe is far more movable, though it 

 never forms as complete a thumb as in many apes, which 

 use their feet, as well as their hands, for prehension. By 

 practice, however, our own toes can be made much more 



