GENERAL ANATOMY. 



last, the fibres form two planes, which are inserted on the two 

 faces of a middle aponeurosis; such as the temporal muscle. 

 Other muscles are still more compound, as the deltoid, the 

 masseter, &c. which result from the union of several penni- 

 form bundles. 



721. The texture of the exterior muscles always results 

 from bundles more or less distinct, which generally terminate 

 at both ends on tendinous tissue; these bundles are composed 

 of visible fasciculi or fibres, themselves resulting from micro- 

 scopic elementary fibres. The cellular tissue and the adipose 

 tissue form for them envelopes and partitions the more dis- 

 tinct in proportion as the bundles are themselves distinct and 

 voluminous. The nerves of these muscles are very abundant, 

 especially in those of the organs of sense, and almost all come 

 from the spinal marrow; few are derived from the grand sym- 

 pathetic, and these last are never alone. 



722. Besides these parts so essential to the muscles, these 

 organs have dependences: these are the fasciae (519,) or en- 

 veloping aponeuroses which surround the muscles, maintain 

 them in their place, and furnish them with partitions by which 

 they are separated, as well as points of attachment; it is also 

 the sheaths and rings that enclose the tendons and prevent 

 their being displaced, and the synovial membranes that facili- 

 tate their sliding. 



723. The muscles are divided, with reference to the mo- 

 tions which they produce, into congenerous and antagonist 

 muscles, according as they concur in the same movements, or 

 produce opposite ones. The motions which take place in 

 the human body, and which are produced by the muscles, are 

 movements of flexion and of extension, of lateral inclination, 

 of rotation in two opposite directions, which in the forearm 

 is distinguished by the terms pronation and supination, of ele- 

 vation and depression, of adduction, abduction, and deduction, 

 of dilation and constriction, of protraction and retraction, &c. 

 From these motions the muscles are called flexors, extensors, 

 pronators, supinators, elevators, &c. 



The antagonist muscles present some differences: in almost 

 all parts of the body, the muscles destined to effect a motion, 



