SECT. 84.] 



MUSCULAR SYSTEM. 



'53 



nerves, even as regards tlieir larger sub-divisions, presents many- 

 peculiarities. Thus it can be shown in most muscles, that the nerves 

 cone in contact with their fibres only at some few limited points, 

 and are never connected tvith them throughout their entire length. 

 With reference to the ultimate termination of the nerves, we find, 

 in all muscles, anastomoses of the finer rig. 71. 



branches, the so-called plexuses. The anas- 

 tomoses between the larger branches are 

 above all to be seen where the entire 

 nervous ramification lies in a very small 

 space; elsewhere they rarely occur, or are 

 whollv absent. On the other hand, those 

 between the finer and finest twigs (terminal 

 plexus, Valentin) are everywhere very nu- 

 merous, and are chiefly parallel to the 

 longitudinal direction of the bundles, in 

 form of elongated rounded meshes. These 

 terminal plexuses, which have sometimes 

 narrower, sometimes wider meshes, and are 

 formed principally by the ramuscules of one 

 small branch, without, however, being alto- 

 gether isolated the one from the other, pro- 

 ceed to form what Valentin calls terminal 



loops ; by which term I understand nothing more than anasto- 

 moses of the branches of the last order, effected by a few primi- 

 tive fibres, or a single one, passing from one twig into the other ; in 

 which it is a matter of indifference whether they run in a straight 

 line, or are curved in the form of loops (fig. 70). 



From the observations of R. Wagner, Luschka and myself, it is 

 now uncpiestionable that free terminations of the nerve-fibres, 

 similar to those known in the muscles of the lower animals, also 

 occur in the human muscles ; and, seeing the results of researches 

 now making in all directions on the terminations of nerves, it 

 may be considered highly probable that the above-mentioned 

 terminal loops are not the ultimate divisions of the primitive 

 fibres, but rather that the fibres which form them, always termi- 

 nate in some other place icith free extremities, either directly or 

 after previously dividing, as was observed by Wagner and me in 

 the muscles of man and mammalia. The trunks entering the 

 muscles consist chiefly of thick nerve-tubes, so that in 100 

 there are on an average about 12 fine ones. In the interior 

 of the muscles thev become more slender, so that the terminal 



Divisions of a primitive 

 nerve-fibre, from a facial 

 muscle of a rabbit, with 

 three apparent twigs run- 

 ning out into points. Mag- 

 nified 350 times. 



