THE MTJSCLES OF THE LIMBS. 55 



tlae muscles seem to be, as it were, higher up in the fore 

 limb than in the hind limb. Nevertheless, several of the 

 muscles correspond very closely. Thus, on the dorsal 

 aspect, the extensor o.ssis vietacarpi pollicis passes from the 

 post-axial side of the proximal region of the antebrachium 

 obliquely to the trapezium and the metacarpal of the pollex, 

 just as its homologue, the tibialis anticus, passes from the 

 post-axial side of the upper part of the leg to the ento- 

 cuneiform and the base of the metatarsal of the hallux ; 

 the two muscles correspond exactly. But the extensors of 

 the phalanges of the pollex, and the deep extensors of the 

 other digits of the manus, arise on the same side of the 

 antebrachium, below the extensor ossis metacarpl pollicis ; 

 while, in the leg, one of the deep extensors of the hallux, 

 and aU those of the other digits, arise still lower down, viz. 

 from the calcaneum. 



Not less remarkable is the contrast between the more 

 superficial sets of extensors in the two limbs. In the fore 

 limb, proceeding from the pre-axial to the post-axial side, 

 the following extensor muscles arise from the external or 

 pre-axial condyle of the humerus : the extensor carpi radi- 

 alis longus to the base of the second metacarpal ; the extensor 

 carpi radialis brevis to the base of the third metacarpal ; the 

 extensor communis digitorum to the four ulnar digits; the 

 extensor minimi digiti to the fifth digit ; the extensor- carpi 

 ulnaris to the base of the fifth metacarpal. In the hind limb, 

 there are no homologues of the first two of these muscles. 

 The homologue of the extensor communis is the long extensor, 

 which arises, not from the femur, but from the fibula. The 

 peron(BUs tertius,* passing from the dorsal face of the fibvda 

 to the fifth metatarsal, is the only representative of the 

 extensor carpi ulnaris. 



On the ventral aspect of the human fore limb, two deep 



* This muscle, which lies alto- often developed in other Mam- 



gether on the dorsal face of the media, but arise on the ventral 



hind limb, and which I have seen face of tlie fibula, and send their 



only in Man, should not be con- tendons below the e.xternal mal- 



founded, as it often is, with one leolus to the extensor sheaths of 



or more muscles, the peroncei 3tii, the fifth, fourth, and even third 



4ii, et tti digiti, which are very digits. 



