NKKVK ENDINGS IN 



ANP TKNPON 



173 



connected with the tendon, or they may join other muscle fiber bundles. 

 The muscle spindles are usually found in the fibrous septa of the peri- 

 invsium. Compared with the adjacent muscle fibers, the intrafu- 

 have a smaller diameter, are less distinctly but more coarsely striped, 

 and contain some centrally located nuclei. 



Either one or several nerve minks enter the spindle, usually near 

 its equator rather than at its poles. The nerve tibers branch repeatedly 



, 



I'u;. U>_. Munn.K THIKD OK v TKKMINAL PLAQVK IN THK. MISCI.K SPINDLE OF AN 



Am i.r t/ 



.1. rings; b\ dendritic branchings: S t spirals. Chlorid of gold preparation. Highly 

 magnified. v Aft or Uiimiii.) 



ill the intracapsular coniuvtivo tissue, and tinally pierce the axial sheath 

 as naked processes which form a rich arborization of terminal fibrils 

 about the intrat'usal muscle tlbers. RutVmi distinguishes three types of 

 terminal nerve fibrils: ( I) annulur. which form rings around the muscle 

 fibers; ^M N/ /><*/. which are spirally twisted about the intrat'usal fibers: 

 and (X) </'W(/n7iV branchiniia. in which the axons break into numerous 

 irregular processes with laminate expansions. 



Motor end-plates for the muscle fibers of the spindle as well as sym- 

 pathetic \n<omotor nerves for its blood-vessels have also been demon- 

 strated within the muscle spindles. 



That the muscle spindles are sensory and not motor organs has been 



