6S ANTHROPOLOGY. 



radius, and is inserted by two tendons, one into the trapezium bone, the 

 other into the upper and back part of the metacarpal bone of the thumb. 

 It serves to extend the first joint of the thumb, and to separate it from the 

 fingers. It also assists in supination. 



Extensor primi internodii poUicis, or extensor minor, arises from the back 

 part of the ulna, below its middle, and from the interosseous ligament and 

 the radius ; it is inserted into the posterior part of the first phalanx. It 

 serves to extend the second joint of the thumb, and to assist the last men- 

 tioned muscle. 



Extensor secundi internodü p)ollicis^ or exterisor major, arises from the posterior 

 surface of the ulna, above its centre, and from the interosseous membrane ; 

 it is inserted into the posterior part of the second or last phalanx ; it extends 

 the last phalanx of the thumb upon the first. 



Extensor indicis, or indicator, arises from the middle of the posterior 

 surface of the ulna and interosseous membrane, and is inserted into the 

 second and third phalanges of the fore finger. It assists the common exten- 

 sor, or produces the extension of the fore finger alone, as in pointing. 



3. Muscles of the Hand. These consist principally of the short muscles 

 of the thumb and of the little finger, of the lumbricalis, and of the interos- 

 seous muscles. 



The short muscles of the thumb are four in number, abductor poUicis, 

 opponens poUicis, flexor poUicis brevis, and adductor poUicis, whose names 

 sufficiently indicate their use. 



The muscles of the little finger are three, abductor minimi digiti, flexor 

 brevis minimi digiti, and adductor or opponens minimi digiti. 



The palmaris brevis is placed just below the skin, at the inner side of the 

 palm of the hand ; it consists of separate fasciculi which arise from the 

 anterior ligament of the wrist, and is inserted into the skin and fat at the 

 inner margin of the hand. It is used in hollowing out the palm. 



The lumbricales are four in number, and arise from the radial sides of 

 the tendons of the flexor profundus. They terminate in little flat tendons, 

 which are inserted into the tendinous expansion of the extensor communis 

 on the back of the first phalanx of each finger ; they serve to bend the first 

 phalanges. 



The interosseous muscles, seven in number, fill up the interstices of the 

 metacarpal bones ; four belong to the palm, and three to the back of the 

 hand. They arise from the base and sides of the metacarpal bones, and are 

 inserted into the sides of the first phalanges, and into the tendinous mem- 

 brane on the back part of the fingers. The palmar are the prior indicis, the 

 posterior indicis, the 'prior anmdaris, and the interosseus digiti auricidaris. 

 The dorsal are the p-ior medii, the posterior medii, and the posterior annu- 

 laris. 



PI. 124, fig. 15", deltoides ; ", pectoralis major; ", biceps ; ^'', pronator 

 teres ; "", flexor sublimis digitorum ; '", supinator longus ; ", flexor carpi radi- 

 alis. Fig. 16% deltoides; ', triceps; ', extensor digiti minimi ; ', extensor carpi 

 ulnaris ; '°, extensor communis digitorum ; ", abductor pollicis longus; ", ex- 

 tensor pollicis brevis ; ", extensor pollicis longus ; '*, external interosseous 

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