1892.] On the Nerve-roots of the Lumbosacral Plexus. 71 



times does not, the 8th taking its place (pre-axial class of innervation) 

 as well as supplying other fibres also. In the cat, in my own experi- 

 ments, the post-axial class, as measured by the above standard, has 

 contained a rather larger number of individuals (twenty-two out of 

 thirty-nine).* 



In experiments on Macacus, also, it early became clear that the 

 types of innervation of the limb-muscles by the spinal roots are con. 

 veniently dealt with as two classes. In fifty-two individuals the 

 reactions obtained place the majority (thirty-one) within a pre-axial 

 class, the broad features of which are as follows : — 



Pre-axial Class of Innervation. 



Ho. of the root excited. Movement produced. 



1st Subthoracic . . Retraction of abdominal wall, near umbilicus 

 in front. 



2nd . . Retraction of lower part of abdominal wall, 



flexion of hip, with some eversion, drawing 

 up of testicle (stronger than with 3rd). 



3rd ,, . . Retraction of lowest part of abdominal wall, 

 drawing up of the testicle, flexion at hip, 

 with marked rotation of thigh outwards and 

 some adduction, some extension of knee. 



4th „ , . Flexion at hip, extension at knee, adduction of 



thigh, eversion of thigh. 



5th ,, . . Flexion at hip, extension at knee, adduction of 



thigh, strong flexion at ankle, drawing up of 

 outer edge of foot, flexion of hallux and digits. 



6th ,, . . Extension at hip, adduction of thigh, flexion 



at knee, extension at ankle, rotation of leg 

 inwards, lifting of outer edge of foot, flexion 

 of digits and hallux at terminal joint with 

 (sometimes) adduction. 



7th „ . * Extension at hip, with slight rotation out- 



ward of the thigh, flexion at knee, extension 

 at ankle, flexion of digits and hallux with 

 adduction of hallux, depression and adduc- 

 tion of root of tail, closure of anus. 



8th „ . . Extension at hip, with slight rotation outward 



of the thigh, flexion at knee, extension at 

 ankle, strong flexion and adduction of hallux, 

 flexion of digits in " interosseal " position, 

 closure and protrusion of anus, root of tail 

 adducted and depressed, perineum pushed 

 down. 



* This agrees with the observations by Langley, loc. ext. 



