Chap. 10.] Connexion of Mufcles i 14* 



of a mufcle is called its belly, and is chiefly compofed 

 of contractile mufcular fibres. That connexion of a 

 mufcle which is leaft moveable is called its origin, that 

 which is moft moveable its infertion : but thefe terms 

 are in many cafes merely relative, for a part of the 

 body which is more fixed in one pofture becomes lefs 

 fo in another. The fibres which compofe a mufcle 

 run either longitudinally, tranfverfely, obliquely, or 

 circularly. If all the fibres which compofe a mufcle 

 run in the fame direction, it is called rectilinear; ra- 

 diated, if the fibres are difpofed like radii ; penniform, 

 if, refembling the plume of a feather, the fibres are 

 fituated obliquely with refpect to the center from which 

 they proceed ; compound, if the fibres run in differ- 

 ent direction* The majority of the large mufcles of 

 the body are compound. 



Moft mufcles have others oppofed to them, which 

 act in a contrary direction, and are called antagonifts. 

 Thus, one mufcle, or one fet of mufcles, bends a 

 limb, another extends it ; one elevates a part, another 

 depreffes it; one draws it to the right, another to 

 the left. By thefe ,oppofite powers the part is 

 kept in a middle direction, ready to be drawn either 

 one way or another, as particular mufcles are thrown 

 into ftronger action. The flexor mufcles exceed the 

 extenfors in ftrength, and for this reafon the eafieft 

 poftures are thofe in which the body or limbs are mo- 

 derately bent. 



When we fpeak of the mufcies of a part, we do not 

 mean thofe which are fituated on it, but thofe which 

 ferve to move it. Thus, what are called the mufcles 

 of the leg, and which are fubfervient to its motions, 

 are placed round the thigh bone; thofe which move 

 the foot, round the bones of the leg, &c, 



In 



