94 



PHYSIOLOGY 



CHAP. 



f.S.Stf. 



o. 



:. 40. Semi-diagrammatic representation 

 of neuro-muscular spindle from adult cat 

 to show complex nerve-endings. (Ruf- 

 fini.) c., capsule; n.t., nerve -trunk; 

 FP.6., Weissmann's bundle; H. (... nerve- 

 fibres ending in the muscle bundles that 

 surround the nemo - muscular spindle ; 

 t.m.p., motor end-plates (after Cipollone) ; 

 t.s.pr., primary sensory endings; t.s.sec., 

 secondary sensory endings. 



muscle-fibres of embryonic appear- 

 ance, invested by a sheath, similar 

 to that of the Pacinian corpuscles, 

 which assumed a spindle form at 

 the point of entrance of the nerve, 

 and were therefore called nerve- 

 muscle spindles. According to A. 

 Cattaneo and Kolliker they are 

 usually found near the tendinous 

 ends of the muscles ; but Sherring- 

 ton and Ruffini found numbers of 

 them also in the fleshy parts of the 

 muscles. A minute anatomical 

 description of the neuro-muscular 

 spindles, and particularly of the 

 different modes in which the nerves 

 terminate in them, was first given 

 by Ruffini (1892-98). Here we 

 can only reproduce one of the most 

 characteristic figures which he oil- 

 served on the cat (Fig. 40). 



The sensory nature of the nerve- 

 muscle spindles was recognised by 

 Korschner (1888) and Ruffini 

 (1892), and experimentally demon- 

 strated by Sherriugton (1894). He 

 saw that the myelinated nerve - 

 fibivs of the spindles underwent no 

 change after section of the ventral 

 spinal roots, and concluded that 

 tbry originated in the cells of the 

 dorsal root - ganglia. Cipollone 

 (1898) by other ingenious experi- 

 ments showed that the fine medul- 

 lated fibres of the spindles as well 

 as the end-plates connected with 

 them are motor fibres and endings, 

 while the large medullated fibres 

 and the plentiful primary and 

 secondary endings of the fusiform 

 swelling are sensory fibres and 

 endings. In rabbits the first de- 

 generate, the second remain per- 

 fectly intact, when necrosis of the 

 grey matter and root cells of the 

 lumbar cord is produced by Sten- 

 sou's method, while the cells of the 



