MUSCLES OF THE LOWER EXTREMITY. 249 



( one dorsal (abductor indicia), 

 \ one palmar. 

 Middle finger, two dorsal. 



S one dorsal, 

 Ring finger J one ^^ 



Little finger ; remaining palmar. 



Relations. By their dorsal surface with a thin aponeurosis which se- 

 parates them from the tendons on the dorsum of the hand. By their pal- 

 mar surface with the muscles and tendons in the palm of the hand. By 

 one side with the metacarpal bone ; by the other with the corresponding 

 palmar interosseous. The abductor indicis is in relation by its palmar 

 surface, with the adductor pollicis, the arteria magna pollicis being 

 interposed. The radial artery passes into the palm of the hand be- 

 tween the two heads of the first dorsal interosseous muscle and the 

 perforating branches of the deep palmar arch, between the heads of 

 the other dorsal interossei. 



Actions. The actions of the muscles of the hand are expressed in 

 their names. Those of the radial region belong to the thumb, and pro- 

 vide for three of its movements, abduction, adduction, and flexion. 

 The ulnar group, in like manner, are subservient to the same motions of 

 the little finger, and the interossei are abductors and adductors of the 

 several fingers. The lumbricales are accessory in their actions to the 

 deep flexors : they were called by the earlier anatomists, fidicinii, 

 i.e. fiddlers' muscles, from an idea that they might effect the fractional 

 movements by which the performer is enabled to produce the various 

 notes on that instrument. 



In relation to the axis of the hand, the four dorsal interossei are ab- 

 ductors, and the three palmar, adductors. It will therefore be seen 

 that each finger is provided with its proper adductor and abductor, two 

 flexors, and (with the exception of the middle and ring fingers) two 

 extensors. The thumb has moreover a flexor and extensor of the 

 metacarpal bone ; and the little finger a flexor of the metacarpal bone 

 without an extensor. 



