On the Nerve Roots of the Lumbo-Sacral Plexus. 243 



"An Experimental Investigation of the Nerve Roots which 

 enter into the formation of the Lumbo-sacral Plexus of 

 Macacus rhesus." By J. S. RlSIEN RUSSELL, M.B., M.R.C.P., 

 Assistant Physician to the Metropolitan Hospital. Com- 

 municated by Professor V. HORSLEY, F.R.S. Received 

 March 22, Read May 18, 1893.* 



(From the Pathological Laboratory, University College, London.) 



CONTENTS. 

 I. Introduction. 

 II. Anatomical introduction. 



III. Operative procedure. 



IV. Division of the subject and analysis of results. 



a. Division of the subject. 



b. Analysis of results. 



Part I. Compound movements obtained by excitation of each whole nerve root. 



Part II. Minute differentiation obtained by excitation of the individual bundles 

 of each nerve root. 



Part III. Direct observation (after dissection) of muscles thrown into action 

 by excitation of the separate nerve roots. 



Corollary to Part III. 



Part IV (Control). Alteration in the action of the posterior extremity in pro- 

 gression, in climbing or in standing, evoked by section of a nerve root. 



Part V (Control). Influence of section of a root or roots in excluding part of an 

 epileptic spasm induced in the limb by intravenous injection of absinthe. 



Corollary to Part V. 



Discussion of results. Conclusions. 



Introduction. 



The first part of my task is to express my great indebtedness to 

 Professor Victor Horsley for enabling me to carry out this investiga- 

 tion under favourable circumstances at the Pathological Laboratory of 

 University College, and for his great willingness at all times to 

 criticise the results which I obtained. 



In a paper on the functions of the nerve roots which enter into the 

 formation of the brachial plexus of the dog,t I gave an account of 

 the views that have been expressed and the work done in connexion 

 with the limb plexuses. The hypotheses as to their significance ad- 

 vanced by Reil,J Scarpa, A. Monro,|| Sommering,^" and others were 



* Part of the expenses connected with this research have been defrayed by a 

 grant from the Scientific Grants Committee of the British Medical Association. 

 t ' Phil. Trans.,' 1892. 

 ' De Nervorum Structural 



' De G-angliis et Plexibus.' 



|| * Observations on the Structure and Functions of the Nervous System.' 

 Tf ' Anatom.,' Pars quinta. 



