866 



ENDINGS OF NEEVES OF GENERAL SENSATIONS. 



1878. They consist of long spindle-shaped bodies, and are usually found near the 

 junctions of the tendons with their muscles. Each is surrounded by a capsule 



which encloses a number of intrafusal tendon 

 fasciculi. The nerve- fibres pierce the side 

 of the capsule and then lose their medullary 



' M1SJ7I!2C/!; H - 1 sheaths; the axis cylinders subdivide, and 



mVratyS ^ their terminal branches ramify between, or 



^^ partly encircle, the smaller tendon bundles 



and end in plate-like expansions. 



(8) Neuro-muscular Spindles (Fig. 746). 

 These are widely distributed throughout the 

 voluntary muscles but are more numerous in 

 the muscles of the limbs than in those of the 

 trunk, and are plentifully found in the 

 muscles of the hand and foot. They have 

 not yet been seen in the intrinsic muscles 

 of the tongue, and only a few are present 

 in the ocular muscles. They lie in the con- 

 nective tissue between the muscular bundles, 

 and each consists of a lamellated capsule en- 

 closing a fasciculus of striped muscular fibres 

 (intra/usal fibres), together with minute 

 blood-vessels and three or four medullated 

 nerve -fibres. These intrafusal muscular 

 fibres display many of the characteristics of 

 embryonic muscle ; they are smaller both in 



PIG. 746._ENmG OF NEBVE-HBRES , MUSCLE lf"g th a " d diame t er than ordinary muscular 



fibres; they contain numerous nuclei near 

 the centre of the spindle where their cross 



nerve-fibres entering spindle ; a, axis cylinders striation is leSS distinct ; they also pOSSeSS 

 terminating around and between the intrafusal more pro toplasm than Ordinary niUSCular 



fibres. The nerve-fibres pierce the side of 

 the capsule, inside which they lose their 

 medullary sheaths and undergo subdivision ; they are then prolonged in a spiral 

 or annular manner around the individual muscular fibres and end in flattened or 

 ovoid enlargements. 



d J- 



SPINDLE (Ruffini). (From Quain's Anatomy.} 

 Three intrafusal muscle fibres are shown : x, 



fibres in b, ring-like ; c, spiral 

 regularly ramified endings. 



and d, ir- 



