LOCOMOTION 349 



1. Bust (trunk and head) ; weight = 50% ^ 



65 



of the whole or = 32-5 kg. Centre of 



gravity at about 0-32 m. from the line of the 



hips ; the dimensions of the cylinder are, . G S 



therefore, : Height, 0-88 m ; radius, 0-13 m. 



(vide fig. 248). The moment of inertia will 



be: 



12 ^' FIG. 248 



2. Upper A rm.~ Weight = 2-20 kg. ; centre of gravity at 

 0-145 m. from the centre of the shoulder joint. Take h = 0-35m ; 

 and compare the segment to a truncated cone. 

 We obtain r = 0-047 m, r f = 0.04 m. 



Applying the formula for the moment of inertia, we have : 



-f- r' J 16 



-. 



9-04 kp" 



3. Fore-arm : M =- ^ ; h = 0-35 m ; r = 0-045 ; r' = 



g 



0-027 m, and the centre of gravity is 0-54 m from the centre of 

 the shoulder joint. Hence : 



I = 0-0037. 



4. The moments of interia of the fingers are approximately 

 as follows : 



Little finger. Ring finger. Middle finger. Index finger. Thumb. 



I = 0-000004 0-000012 0-000014 0-000012 0-000006 



5. In the whole upper limb the centre of gravity falls at about 

 T % 5 o of the length from the shoulder joint, i.e., 0-32 m. If the 

 fist is closed we have approximately h = 0-70 m. As P = 4-20 

 kg and r = 0-047 m, and r' = -027 m, we can calculate that 

 I = 0-03 approximately. 



6. In the lower limb the lower leg will be considered separately, 

 and then the whole limb. 



Lower Leg. P = 4-400 kg (foot included) ; h = 0-44 m ; 

 r = 0-062 m ; r' = 0-038 m. From these figures : 



I = 0-013. 



For the whole of the leg : P = 12 kilogrammes ; h = 0-88 m; 

 r = 0-086 m ; r' = 0-038 m. Whence 



I = 0-146. 



According to the measurements and calculations, the centre of 

 gravity of the lower limb, in the adult, is about 0-38 m. from the 

 centre of the hip joint. The radius of gyration is deduced from 

 the formula I = Mp 2 , which gives p = 0-34 m. 



