98 Anatomy Applied to Medicine and Surgery. 



the radial side of the index finger ; that for the metacar- 

 pal, lies between the index and middle fingers ; while the 

 lines corresponding to the spaces between the metacarpal 

 bones of the middle, ring and little fingers, represent the 

 dorsal interossei branches. 



Landmarks for the Muscles of the Thumb. These 

 muscles, from above downwards, are, the opponens pollicis, 

 the abductor, the flexor brevis and the adductor pollicis. 

 To identify them, place the index finger on the front of 

 the thenar eminence, so that its tip shall touch the base of 

 the first phalanx and the body of the finger lie on the 

 ridge of the trapezium, then the space above the finger 

 corresponds to the opponens pollicis, that beneath the fin- 

 ger to the abductor pollicis, the space one-quarter of an 

 inch below the finger, to the flexor brevis pollicis, while 

 the rest of the thenar eminence represents the adductor 

 pollicis. 



For the Muscles of the Little Finger. Place the index 

 finger so that its tip touches the base of the first phalanx 

 and its body rests on the hook of the unciform bone, the 

 finger will then lie over the abductor minimi digiti, and 

 the space, one-quarter of an inch external to it, will cor- 

 respond to the flexor brevis minimi digiti. 



Functions of the Muscles of the Hand. 

 Those on the palm, belonging to the thumb and little fin- 

 ger, have actions corresponding to their respective names, 

 while the dorsal and palmar interossei, being inserted into 

 the sides of the first phalanges of the fingers, are flexors 

 of these phalanges. In addition to this action of flexion, 

 the interossei are extensors of the second and third phal- 

 anges, because of their insertion, along with the lumbri- 

 cales, into the expansion of the common extensor tendon 

 on the back of the first phalanx. These actions of the in- 

 terossei and lumbricales are evident in the making of the 



