THE MUSCLES 113 



wrongly describe these tendons as being associated with the M. ext. 

 dig. communis. They have nothing whatever to do with this muscle 

 (cf. Sieglbaur and Perrin). 



The details of the several digits will be dealt with individually. 



MM. abductor et extensor digiti I (m.a.e. i). Sieglbaur. 



MM. abductor et extensor hallucis . . Osawa (1902). 



These muscles arise from the dorsal surfaces of the intermedium and 

 centrale and pass obliquely across the tarsus. The abductor portion 

 is inserted on the lateral face of the metatarsal, while the extensor 

 portion is distinguishable therefrom by its tendinous insertion on the 

 phalanx of the same digit. The abductor portion of this muscle is 

 probably identical with Humphry's M. supinator -pedis and Hoff- 

 mann's M. fibulae-metatarsum II (see also p. 1 1 1). 



The M. extensor digiti brevis superficialis II arises alongside the pre- 

 vious muscle from the intermedium and centrale^ and passes across the 

 tarsus to the level of the base of the proximal phalanx of the second 

 digit. Here it passes into a tendon which is inserted on this phalanx, 

 and on the base of the terminal one, in the manner already described. 



The M. extensor digiti brevis superficialis III arises by two heads : 

 (i) from the intermedium together with I and II, and (ii) from the 

 dorsal surface of the fibulare. The two heads pass into a common 

 tendon which is inserted on the bases of the phalanges of the third 

 digit. 



The M. extensor digiti brevis superficialis IV has a single origin from 

 the fibulare and has the typical insertions on the phalanges of the 

 fourth digit. 



The M. extensor digiti brevis superficialis V also arises from the fibu- 

 lare and is inserted on the bases of the phalanges of the fifth digit. 

 It is a relatively slight muscle. 



The MM. extensores digitorum breves profundi of the several digits 

 arise from the respective basal elements of the tarsus. It is note- 

 worthy, however, that the muscle to the first digit arises from the 

 united basals of the first and second digits and not from the cart, pre- 

 hallucis (cf. p. 42). They are all short feeble muscles and are 

 inserted on the dorsal side of the tendons of the corresponding 

 superficial portions at about the level of the distal ends of the 

 metatarsi. 



Eisler describes and figures three layers of extensor digiti muscles 



4038 I 



