126 



lumbo-sacral plexus in man may be mentioned those of Arnould^), 

 Eisler2) and Paterson^). 



Important studies concerning the lumbo-sacral plexus in the higher 

 mammals have been carried on by Ruge*), Sherrington^), Langley*^), 

 Bolk') and Paterson^). 



Interesting investigations on variation in the lumbo-sacral plexus 

 of Amphibia have been carried on by Adolphi^), and by Waite^*'), 

 of lizards by St. George Mivart and R. Clark ^^) , of fish by 

 V. Davidoff ^2). 



In general these investigators have been mainly concerned with 

 one of two problems: 1) the variation in the number and relative 

 position of the spinal nerves from which the limb nerves arise; and 

 2) the relation of the segmental spinal nerves to the muscles and 

 cutaneous areas of the limb and the extent to which segmentation 

 can be demonstrated in the limb. 



With the former of these problems alone are we concerned in 

 the present paper. It has been clearly shown that considerable 

 variation exists in the position of the limb plexuses relative to spinal 



1) Arnould, Contributions ä I'etude de la structure intime du plexus 

 sacre, These Bordeaux 1892. 



2) EisLER, Der Plexus lumbo-sacralis des Menschen, Halle 1892. 



3) Paterson, The Origin and Distribution of the Nerves of the 

 Lower Limb. Journal of Anatomy and Physiology, Vol. 28, 1894, 

 p. 84 and 169. 



4) RuGE, Verschiebungen in den Endgebieten der Nerven des 

 Plexus lumbalis der Primaten. Morph. Jahrb., Bd. 20, 1893. 



5) Sherrington, Notes on the Arrangement of some Motor Fibres 

 in the Lumbo-Sacral Plexus. Journal of Physiology, Vol. 8, 1892. 



6) Langley and Anderson, The Innervation of the pelvic and 

 adjoining Viscera. Journal of Physiology, Vol. 13, 15 and 20, 1896, 

 p. 393, Vol. 22, p. 349 and 373. 



7) BoiiK, Beziehungen zwischen Skelet, Musculatur und Nerven der 

 Extremitäten. Morph. Jahrb., Bd. 21, 1894, p. 241. 



8) Patekson, The Limb Plexuses of Mammals. Journal of Anatomy, 

 Vol. 21, 1887, p. 611. 



9) Adolphi, Ueber Variationen der Spinalnerven und der Wirbel- 

 säule. Morph. Jahrb., Bd. 19, 1892, p. 313 ; Bd. 22, 1895, p. 449 ; Bd. 25, 

 1896, p. 115. 



10) F. C. Waite, Variations in the Brachial and Lumbo-sacral 

 Plexi of Necturus. Bull. Comp. Zoology Harvard, 1897. 



11) St. George Mivart and R. Clark, On the sacral Plexus of 

 Lizards and other Vertebrata. Trans. Lin. Soc, Ser. 2, ZooL, Vol. 1. 



12) V. Davidoff, Ueber die Varietäten des Plexus lumbo-sacralis 

 von Salamandra maculosa. Morph. Jahrb., Bd. 9, 1884. 



