191 



Variations in the nerve-supply of the flexor brevis 



pol li eis in Man. 

 Outer head {Ä-\-B) supplied by deep branch of ulnar 



nerve alone 5 cases 



Outer head (Ä-{-B) supplied by twigs from ulnar and 



median 19 „ 



Outer head {Ä-{-B) supplied by median; inner head (D) 



by ulnar 5 „ 



Median giving twigs to both heads {Ä -\~ B -\- D) \ inner 

 head (D) also receiving an ulnar nerve-supply ... 2 „ 

 Some years previous to this I had obtained similar evidence of 

 variations in the nerve-supply of the intrinsic muscles of the hand and 

 foot in different mammals'). It is important to note that even when 

 our observations are confined to one species deviations may be obser- 

 ved. Professor Flemming remarks: „Die Nerven der Köpfe B und C 

 hat, soviel ich finde, noch niemand näher präpariert". In Dr. Brooks' 

 paper the ulnar-supply of B is described and important conclusions 

 are deduced from it. 



In only one instance have I succeeded in tracing the nerve-supply 

 of the interosseus primus volaris and this was in the hand of a Negro. 

 It apparently came from the deep branch of the ulnar nerve, but in 

 the light of the foregoing facts I do not consider that this invalida- 

 tes the doctrine advanced by v. Bischoff, viz : that the ulnar head of 

 the flexor brevis and the interosseus primus volaris are one and the 

 same muscle. Indeed it would appear that this muscular slip may be 

 innervated differently in difierent animals. Thus Dr. Brooks has 

 shown me a dissection of the hand of the Orang in which it is sup- 

 plied by the ulnar nerve and an other of the hand of the Gibbon in 

 which it is supplied by the median nerve. 



I certainly was not prepared to find Professor Flemming throw 

 doubt upon the double-character of the flexor brevis hallucis and ex- 

 press a desire to deprive it of its outer or fibular head. He states that 

 this head is supplied by the deep branch of the external plantar nerve. 

 In this he follows the description of Henle*) and also of Schwalbe ^). 

 I have carefully studied the nerve -supply of this muscle but have 

 never seen such a branch. Throughout the entire class of mammalia I 



1) The relation of nerve-supply to muscle-homology. — Journal of 

 Anatomy and Physiology, Vol. XVI. 



2) Nervenlehre, p. 593. 



3) Neurologie. 



