374 



APPLIED PHYSIOLOGY 



Tendon 



If the power is farther away from the fulcrum than the 

 weight, it will move a weight greater than itself, but if it 

 is a less distance away, it can move only 

 a weight less than itself. 



A bone is a rigid bar. The joint is 

 thfe fulcrum upon which it turns. The 

 power is the contraction of the muscles 

 which are attached to it. The weight 

 is the weight of the body or limb to- 

 gether with anything which may be 



Muscle, gasped. 



668. Levers of the first class are not 

 numerous in the body. The foot when 

 pressing down with the toes, and the 

 head when it is raised, are two examples. 



669. Levers of the second class are 

 also few. The best example is the foot 

 when standing on the toes. The power 

 is attached to the heels and is furnished 

 by the muscles upon the back side of 

 the leg below the knee. They end in a 

 very strong tendon called the tendon of 

 Achilles, which can be felt under the 

 skin above the heel. It is the largest 

 tendon in the body. 



670. Levers of the third class are 

 the most numerous. The foot in rais- 

 ing a weight upon the toes is an example. In nearly 

 all joints of the arms and legs the power is furnished 

 by the muscle attached to a bone near the fulcrum 

 .or joint, while the weight is farther away or near the 

 outer extremity of the bone. Most of these muscles are 

 so attached to their bones that they must exert a force 



Right forearm. 



