THE RELATION BETWEEN THE OCCURRENCE OF 



WHITE RAMI FIBERS AND THE SPINAL 



ACCESSORY NERVE. 



By A. H. Roth, A.B., M.D., 



Instructor of Anatomy in the University of Micliigan. 



(With an Addendum by J. Playfair McMurrich) 



With One Figure. 



In two important papers published in 1886 and 1889 

 Gaskell pointed out that the spinal accessory nerve in the dog 

 contained in its upper part fine calibered fibers resembling those 

 which formed the visceral efferent fibers of the thoracic nerves, 

 and concluded that these fibers represented the white rami 

 communicantes of the upper cervical nerves. Furthermore he 

 revived, in a new form, the view propounded long before by 

 Beli,, in supposing that instead of but two roots, each segment- 

 al nerve of the body possessed in addition visceral roots, which, 

 so far as their efferent fibers were concerned, were associated 

 with a lateral column of cells in the central nervous system. 

 Throughout a considerable portion of the spinal region these 

 visceral efferent fibers form the white rami communicantes ; in 

 the cranial region they are represented by those fibers which, 

 since the embryological studies of His demonstrated so clearly 

 their distinctness, are generally known as the lateral motor 

 roots. And since the fibers of the lower roots of the spinal 

 accessory belong to the lateral motor series, and according to 

 Gaskell's view the upper roots represent white rami communi- 

 cantes, tliere follows the conclusion that a correlation should 

 obtain between the spinal accessory nerve and the occurrence 

 of white rami passing from the spinal nerves to the sympathetic 

 cord. 



In the dog Gaskell found in the anterior roots of the 

 spinal nerves from the loth to the 25th, large numbers of 



