86 



ANIMAjl mechanics. 



length, and weighing, when dried at 2 1 2° F., five grains, had 

 an original cross section of 0.0401 sq. inches. 



If we unite Tables XII. and XIII. into one Table, show- 

 ing the proportion between the cross sections of the muscles 

 and their tendons, we obtain the following results : — 



Table XIV. — Ratio of Cross Section of Muscle to that of 

 Tendon in Man. 



Muscle. 



Ratio of Cross 

 Section of Muscle 

 to that of Tendon. 



Force of Muscle. 



1. 



Biceps humeri, . . . .. 



28.2 



91.78 lbs. av. 



2. 



Palmaris longus, . . . 



26.4 



15.18 * 



3- 



Ext. carp. rad. long., . . 



26.2 



59- 8 9 „ 



4- 



Ext. carp. rad. brev., . . 



18.4 



4»-53 n 



5- 



Biceps humeri (long head), 



18.0 



38.86 „ 



6. 



FL poll, long., .... 



*5-7 



23-38 „ 



7. 



FL carp, rad., .... 



'5i 



24.00 ,, 



8. 



Ext. carp, uln., .... 



10.7 



21.74 n 



9- 



FL dig. subl., 



93 



63-38 „ 



10. 



FL dig. prof., 



8.3 



78.76 „ 



11. 



Ext. oss. met. poll., . . . 



7-7 



22.87 „ 



12. 



Fl. carp, uln., 



7.2 



*8.66 „ 



.3. 



Brachiseus, 





94-65 >, 



From an examination of the foregoing Table, it is evident 

 that the muscles which experience least resistance have the 

 largest coefficient of cross section as compared with their respec- 

 tive tendons. Thus the biceps humeri has a coefficient of 28.2 as 

 compared with its radial tendon, and a coefficient of 1 8.0 only, 

 as compared with its scapular tendon, which is exposed to the 

 friction of the head of the humerus. Again, the ext. oss. met. 

 poll., whose tendon winds round the radius, and has the duty 

 imposed on it of binding down the tendons of the radial ex- 

 tensors of the wrist, has the coefficient of 7.7, as compared 

 with 26.2 and 18.4, the coefficients of the comparatively free 

 tendons of those extensors. 



