6 Dynamic Theory 



leap has been taken. There is a difference in structure between the 

 human hand and human foot both in the bones and in the muscles. In 

 the bones the chief difference is between those connecting the hand and 

 foot with the arm and leg respectively. The " carpus, " which is the 

 part of the hand connected to the radius bone of the fore-arm, is com- 

 posed of eight bones in two rows of four each, the upper four being 

 joined to the radius and the lower four to the metacarpus or the five 

 bones leading through the palm to the fingers and thumb. 



FIG. i. 



FIG. 1. Human hand. Above the line 

 are the eight bones of the carpus or wrist. 

 From a to 6 are the five metacarpal or hand 

 bones. From 6 to c are the finger bones or 

 digits, each finger containing three sec- 

 tions or phalanges, and the thumb two. 

 Compare with hand of gorilla the bones of 

 which are the same as in man, same with 

 the chimpanzee, while the carpus of orang 

 and most other apes has nine bones instead 

 of eight. 



FIG. 2. 

 FIG. 2. Carpus or wristbones. 



1. Ulna. 



2. Radius. 



4. Metacarpal of Thumb. 



8. " Little finger. 



5. Scaphoid. 



L. Lunare (Semilunar). 



C. Cuneiform. 



P. Pisiform. 



Tm. Trapezium. 



Ts. Trapezoides. 



M. Magnum. 



U. Unciform. 



The ''tarsus " of the foot joins it to the tibia 

 bone of the leg and corresponds with the carpus 

 of the hand. It is composed of seven bones, 

 however, instead of eight, the lower four of 

 which connect with the five bones called the 

 metatarsus which lead down through the foot to 

 the five toes; of the other three, one projects 

 backward to form the heel ( os calcis), another 

 (the scaphoid) is forward of this, connecting 

 with the lower four of the tarsal bones, while 

 the third ( the astragalus ) is between and over 

 HAN sameboTes L a^fi| h 2 Wing these two, and resting upon them, it supports 

 the tibia of the leg. The lower bones of hand and foot are alike in 

 number and kind, differing only in proportional lengths and in the flexi- 

 bility of some of the joints. 



