PERIPHERAL NERVOUS SYSTEM 



231 



FIG. 176. DIAGRAM ILLUSTRATING THE ORIGIN, COURSE, AND TERMINATION OF 

 THE MOTOR AND SENSORY FIBRES OF THE SPINAL NERVES, AS WELL AS THE 

 RELATIONS OF THE SENSORY COLLATERAL FIBRES TO THE POINTS OF ORIGIN 

 OF THE VENTRAL ROOTS. (After M. v. Lenhossek. ) 



The spinal cord is shown as if transparent. The fibres of the ventral roots 

 arise from the motor cells of the ventral cornua of the gray matter (a) and 

 end in tine branches on the striated muscle-fibres (c). The spinal ganglion 

 (d) is shown relatively much larger than in reality, and in it only a single 

 unipolar nerve-cell is represented : the centripetal fibre of the latter is seen 

 entering the dorsal root, and at e bifurcates in the spinal cord into an anterior 

 (/) and a posterior (g) branch, each of which ends freely in the gray substance, 

 first giving off numerous collateral fibres (h). The centrifugal fibre of the cell 

 iu the spinal ganglion forms a peripheral sensory fibre extending to the skin, 

 where part of it is shown ending in fine branches in the epiderm (i), anothei 

 part forming a coil in connection with a tactile corpuscle (). 



mediate group known as the spino-occipitcd ncwes. By their means 

 a physiological connection is established between the periphery of 

 the body and the central nervous system both in centripetal and 

 centrifugal directions. 



