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



No. of root excited. Muscle thrown into action. 



slight (< peroneus brevis), peroneus brevis, 

 gastrocnemius external head, internal head, 

 plantaris, tibialis posticus, flexor longus 

 digitorum, soleus, flexor longus hallucis, 

 extensor brevis digitorum, flexor brevis digi- 

 torum, adductor hallucis, adductor minimi 

 digiti, flexor accessorius, flexor brevis hal- 

 lucis, flexor brevis minimi digiti, interossei 

 and lumbricales, obturator internus, quad- 

 ratics fern oris, gemelli superior et inferior, 

 pyriformis (the larger part of, especially the 

 lateral part), deeper part of sphincter ani, 

 semitendinosus, semimembranosus, biceps, 

 adductor magnus (part of), popliteus, gluteus 

 medius. 



8th Subthoracic . . Biceps (< than semimembranosus), semitendi- 

 nosus ( < than semimembranosus) , semimem- 

 branosus, gluteus maximus, gluteus medius. 

 gastrocnemius internal head ( < than exter- 

 nal), external head, soleus, adductor hallucis, 

 flexor accessorius, adductor minimi digiti. 

 adductor hallucis, obturator internus, quad- 

 ratus femoris (slight), gemelli superior et 

 inferior, pyriformis (small part, chiefly me- 

 sial), sphincter ani, flexor brevis hallucis, 

 flexor brevis minimi digiti, lumbricales and 

 interossei. 



9th „ Sphincter vaginae, obturator internus (slightly). 



The remaining twenty-one individuals formed a " post-axial " class, 

 with the following broad characters in common : — 



Root. Movement. 



1st Subthoracic. . Retraction of abdominal wall. 

 (1st lumbar) 



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

 drawing up of testicle, slight flexion at hip. 



3rd ,, .. Contraction of lower part of abdominal wall, 

 drawing up of testicle (stronger than with 

 2nd), flexion at hip, slight flexion at knee, 

 slight rotation outwards of thigh. 



4th „ . . Drawing up of testicle (slight) ?, contraction 

 of lower part of abdominal wall, flexion at 



