disteibution and foiim 267 



Striated Muscles. 



Distribution and form. — (See Ex. LIII.) If we remove 

 carefully the skin of any vertebrate animal, we find masses 

 of flesh or meat just below this skin. This flesh is composed 

 mainly of striated muscle tissue. We may note further, 

 that this mass of flesh is composed of separate bundles of 

 varying size and shape, each bundle covered with a glisten- 

 ing sheath and attached to the bones only at certain points. 

 Such a bundle constitutes a separate muscle, and there are 

 five 'hundred of such separate bundles or muscles in our 

 body. In their sum they determine the form of the animal 

 body. Although there are so many of these muscles, they 

 admit of classification under comparatively few heads. 

 The type forms are as follows: 



Bellied muscles. These muscles, of which the biceps 

 muscle already referred to is a type, receive their name 

 from their shape. They are spindle-shaped bundles with 

 a swelling or belly in 

 the center, and taper 

 at each end into one 

 or more white, in- 

 elastic cords called 

 tendons (see Fig. 114). 

 These tendons serve to attach the body of the mus- 

 cle to the bones which it is to move. As these muscles 

 contract, the bell}' swells and the spindle shortens, draw- 

 ing the two attached ends nearer together. If these ends 

 are attached to movable bones, these bones must necessa- 

 rily move as the spindle shortens. In some (jases, the bones 

 at each end move. In others, only one of the bones moves. 

 The end of the muscle that is attached to the bone 



Fie. 114— Bellied muscle; a, belly; J, b, tendons. 



