I020 



HUMAN ANATOMY 



Nerve-fibre- 



Intrafusal 

 fibres' 



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Sheath- 





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 Capsule 



lymph-space. Each spindle receives usually several meduilated nerve-fibres, which, 

 after incorporation of their sheaths of Henle with the capsule, pierce the latter at 

 various points and proceed to the individual muscle-fibres. The terminal relations 

 of the nerves to the intrafusal fibres have been studied by means of the newer 



methods especially by Rufifini, 

 •^ Mo. 876. , HuberandDeWittandDogiel. 



After repeated division during 

 their course through the cap- 

 sule and periaxial space, the 

 nerve-fibres pierce the axial 

 sheath, lose their medullary 

 coat and terminate either as 

 one or more ribbon-like 

 branches that encircle the mus- 

 cle-fibres in annular or spiral 

 windings, or, after further 

 subdivision, as branched telo- 

 dendria in which the ultimate 

 fibrils end in irregular spherical 

 or pyriform enlargements. 



Neurotendinous End- 

 ings. — These end-organs, 

 described by Golgi and sub- 

 sequently more fully investi- 

 gated by Kolliker, Ciaccio, and 

 Huber and DeWitt, in their 

 general architecture resemble 

 closely the sensory endings in 

 muscle. They lie embedded 

 within the interfascicular con- 

 nective tissue and are usually 

 found in the vicinity of the 

 junction of muscle and tendon. 

 Like the neuromuscular end- 

 ings, the tcndo7i- spindles are 

 long fusiform structures, from 

 I.— 1.5 mm. in length, sur- 

 rounded by a fibrous capsule. 

 The latter encloses a group of 

 from eight to twenty intrafusal 

 tendo7i fasciculi, which are 

 smaller and apparently less 

 mature than those of the sur- 

 rounding tendon-tissue. The 

 intrafusal fasciculi are invested 

 by a fibrous axial sheath be- 

 tween which and the capsule 

 lies a periaxial lymph-space. 



On reaching the spindle, 

 after repeated branching, the 

 meduilated nerve-fibres pene- 

 trate the capsule, with which 

 their fibrous (Henle's) sheaths 

 blend, and undergo further 

 division. The medullary coat is lost after they pierce the axial sheath, the naked axis- 

 cylinders breaking up into smaller fibrils that extend along the intrafusal fasciculi. The 

 terminal ramifications, applied to the surface of the fasciculi, vary in details (Huber). 

 Some arise as short lateral branches that partly encircle the fasciculi and end in 

 irregular plate-Hke expansions, while others terminate between the smaller fascicuH. 



Axial_ 

 sheath 



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■Nerve-fibre 



Axial 

 " sheath 



Tendon 

 fasciculi 



tglj 



/I, neuromuscular ending; ^.neurotendinous ending in longitudi- 

 nal section, methylene-blue staining. X 260. ( Drawn from preparation 

 made by Professor Huber.) 



