PERIPHERAL NERVE TERMINATIONS. 



369 



6. Pacinian Corpuscles. These are oval bodies 

 and the larger ones are easily 



visible to the naked eye, being 

 over 2 mm. long. Structurally 

 they seem related to the corpus- 

 cles of Herbst. They are found 

 in the dermis of the hand and 

 foot, particularly along the lower 

 surface of the fingers and toes. 

 They are also found in the joints, 

 the peritoneum, pleura, pericar- 

 dium, and are especially abun- 

 dant in the mesentery. The 

 greater portion of the corpuscle 

 consists of concentric lamellae of 

 connective-tissue origin. Be- 

 tween these flat endothelial cells 

 intervene. A granular core 

 forms the axis of the corpuscle, 

 in the center of which the axis 

 cylinder may be traced. Usually 

 one large nerve fiber goes to each 

 corpuscle. After entering the 

 core this forms a plexus of fine 

 branches and becomes non-med- 

 ullated. 



7. Tendon and Muscle Spin- 

 dles. A tendon spindle is an ex- 

 pansion of tendon bundles en- 

 closed in a well defined connec- 

 tive-tissue sheath. The 



Fig. 263. Neuroten- 

 dinous nerve-end organ 

 from rabbit; teased 

 preparation of tissue 

 stained in methylene- 

 blue (Huber and De 

 Witt, "Jour. Comp. 

 Neurol.," vol. x). 



nerve 

 fiber enters the middle of the spindle, divides re- 



24 



