OP THE EXTERIOR MUSCLES. 



According to their form the muscles are moreover distin- 

 guished by the terms broad, long and short. 



The broad muscles belong to the trunk; some of them ex- 

 tend from the trunk to the members, and are then elongated 

 in this last part of their extent. 



The long muscles appertain to the members, and are in ge- 

 neral disposed in layers, the most exterior being the longest 

 and the straightest, the more profound being much shorter 

 and more oblique: a disposition important to be known in the 

 practice of amputations, since the muscles, unequal in length, 

 must contract unequally. 



The short muscles are met with in the trunk and in the 

 members, near the articulations. 



714. The direction of the muscles is that of a line ex- 

 tended, passing through their centre, from one extremity to 

 the other; it is often very different from that of its fibres, and 

 this last is the most important circumstance. When all the 

 fibres are straight and parallel to each other, the power of the 

 muscle, which is equal to the sum of the power of all the 

 fibres, operates in a manner parallel to the direction of these 

 fibres. But if the fibres are oblique with respect to each 

 other, the intensity and the direction of the power will be 

 different. 



715. In general there is perceived in each muscle a body 

 or belly, and two extremities, the one of origin, the other of 

 insertion. The body is the fleshy part, the extremities are 

 ordinarily tendinous: the extremities are also frequently dis- 

 tinguished into point of origin, of adhesion or stationary point, 

 and in moveable point or of insertion; but many of the mus- 

 cles will not accommodate themselves to this description. 

 Those to which it would best apply are certain muscles of the 

 members, which are elongated, swelled in the middle, because 

 of the disposition of their fleshy fibres; formed of a short ten- 

 don at their superior extremity, generally the most fixed, and 

 of a long tendon at the other extremity, generally the most 

 moveable. But in these muscles, the movement may be divid- 

 ed between the two points, and sometimes may even be en- 

 tirely executed by the point most elevated. 



