ANIMAL MECHANICS. 



105 



The plantaris muscle takes an origin from the back of the 

 outer condyle of the femur, and is inserted into the plantar 

 fascia that passes over the os calcis, 

 and gives origin to the perforate ten- 

 dons of the toes. The tendon of 

 plantaris, flowing freely over the 

 heel, becomes partly inserted into 

 the tendon of the long flexor of the 

 toes, in the centre of the foot, and 

 partly terminates in the three per- 

 forate flexors that correspond with 

 the flexor brevis of other animals. 

 The long flexor muscles arise from 

 the entire back of the fibula, and 

 lower half of the tibia, and unite 

 into a tendon that represents Jl. dig. 

 long, and fl. hall. long, united ; this 

 tendon is joined, as already described, 

 in the sole of the foot, by the ten- 

 don of the plantaris muscle and flexor 

 brevis united. 



The relative strengths of the fore- 

 going tendons, measured by their cross sections, are as fol- 

 lows, representing the total cross section of the flexors of 

 the leg by 100 : — 



Rhinoceros (long flexor tendons of toes). 



Weight. 



1. Plantaris, 44.3 per cent. 3.5 oz. av. 



2. Flexores longi dig. et hall., 55.7 ,, 21.0 >, 



Total, . . . 100.0 



f/.longr pi. 



PL Tendon of plantaris. 

 Fl. long. Joint tendon of fl. hall, 

 long and fl. dig. long. 

 1, 2, 3, deep flexors of toes. 

 1'. 2'. 3'. perforate flexors of toes. 

 Fig. 12. 



