BONES, MUSCLES, EXERCISE, AND REST. 



269 



623. These muscles, distributed and arranged in nature's 

 most skilful and benevolent manner, are the source of al) 

 our power of motion. By these we walk, we lift, we strike, 

 we eat and swallow, we breathe and cough, we speak, wink, 

 nod the head, bend the back, and do all our work. A pal- 

 sied limb, whose muscular power is lost, is as motionless as 

 the limb of the dead. 



624. The muscles are mostly attached to different bones 

 at their two ends, and by their contractions move these bones 

 on or toward each other, as at the joints. But some muscles 

 are intended to move only the flesh, and are, therefore, 

 attached only to the flesh, at least at one end, as in the face. 



FIG. LII. Muscles of the Face. 



a, Frontal muscle, raises the 

 eyebrows, and wrinkles the fore- 

 head. 



b, b, Circular muscles, close 

 the eye. 



c, d, Muscles that raise the 

 corners of the mouth. 



e, Circular muscle, closes the 

 mouth. 



/, /, Muscles that draw down 

 the lower lip. 



The muscles (Fig. LII. , a) that wrinkle the forehead and 

 draw up the eyebrows, are attached to the bone above, and to 

 the skin and flesh below. The muscles that raise and draw 

 down the corners of the mouth and the lips (Fig. LII. c, d,f) 

 are attached to the bones of the two jaws and the cheek by 

 one end, and to the lips by the other. The muscles of the 

 eye ball (Fig. LXVI1I.) are fixed by their inner ends to the 

 bone within the socket of the eye, and by their outer ends to 

 the ball. By their various contractions they roll the eye. 

 23* 



