88 



SIR CHARLES BELI/S DIVISION OF NERVES. 



membrane ; and, according to Beil, 1 of an external envelope, called 



neurilemma, which, in the 

 opinion of most anatomists, is 

 nothing more than an areolar 

 envelope, similar to that which 

 surrounds the vessels and mus- 

 cular fibres. 



Until of late years, the 



Represents a Nerve consisting of many smaller Cords nerves Were Universally divided, 

 or Funiculi wrapped up in a common cellular aCCOrdinp* to their Griffin, into 



Gk^o + U T T. T -i 



encephalic and spinal; but, 



igiyumculu. drawn out from mQre recentlj? anato mical di- 



visions have been proposed, 

 based upon the* uses they appear to fulfil in the economy. For one of 

 the most beautiful of this kind we are mainly indebted to Sir Charles 

 Bell. It has been already seen, that the encephalic nerves are con- 

 nected with the encephalon by one root, whilst the spinal nerves arise 

 from two ; the one connected with the anterior tract of the spinal 

 marrow, the other with the posterior. If these different roots be ex- 

 Fig. 20. 



U ,",e T .l; ce 



fts B iVc. s S) fn " iculusdrawno ' Itfrom 



A portion of the Spinal Marrow, show- 

 ing the Origin of some of the Spinal 

 Nerves. 



1. Anterior or motor root of a spinal 

 nerve. 



2. Posterior or sensory root. 



3. Ganglion connected with the latter. 



Plans in outline, showing the Front A, and 

 the Sides B, of the Spinal Cord, with the 

 Fissures upon it ; also sections of the 

 Gray and White Matter, and the Roots 

 of the Spinal Nerves, 

 a, a. Anterior, p, p. Posterior fissure. 6. 

 Posterior, and c. Anterior horn of gray mat- 

 ter, e. Gray commissure, a, e, c. Anterior 

 white column, c, e, b. Lateral columns, 

 a, e, b. Antero-lateral column, b, e, p. Pos- 

 terior columns, r. Anterior, and s. Poste- 

 rior roots of a spinal nerve. 



perimented on, we meet with results varying considerably. If we divide 

 the anterior root, the part to which the nerve is distributed is deprived 

 of motion ; if the posterior root be cut, the part is deprived of sensi- 

 bility. We conclude, therefore, that each of the spinal nerves consists 



De Structura Nervorum, Hal. 1796. 



