m ANTHROPOLOGY. 



and fingers : tbese are the flexors. A second, nearly allied to these, has 

 the power of rolling the radius across the ulna, so as to turn the palm down- 

 wards: these are the pronators. The extensors can extend the forearm, 

 hand, and fingers ; and a fourth set, the supinators, can turn the palm of 

 the hand upwards. The pronators and flexors arise chiefly from the internal 

 condyle, and from the inner or ulnar side of the forearm. 



The pronators and flexors arising from the inner side of the forearm are 

 eight in number, arranged in a superficial and a deep layer. The superficial 

 are the pronator teres, flexor carpi radialis, palmaris longus, flexor digi- 

 torum sublimis, and flexor carpi ulnaris. The deep are the flexor digitorum 

 profundus, flexor pollicis longus, and the pronator quadratus. 



Pronator radii teres arises from the anterior part of the internal condyle 

 and from the coronoid process of the ulna ; it is inserted into the outer and 

 back part of the radius about its centre. Use: to pronate the hand and 

 bend the forearm. 



Flexor carpi radialis arises from the inner condyle and from the inter- 

 muscular septa, and is inserted into the base of the metacarpal bone of the 

 index finger. 



Palmaris longus arises from the inner condyle, and is inserted into the 

 annular ligament and the palmar aponeurosis. It bends the hand and 

 stretches the palmar fascia. 



Flexor car2yi ulnaris arises from the internal condyle, and is inserted into 

 the pisiform bone. 



Flexor digitoi'um sublimis perforans arises from the internal condyle and 

 internal lateral ligament, from the coronoid process, and from the portion 

 of the radius below its tubercles and internal to the pronator teres. It ends 

 in four tendons, two anterior for the middle and ring finger, and two 

 posterior for the index and little finger ; at the first phalanx of each finger, 

 each tendon becomes inclosed in a strong sheath with one of the deep 

 flexors. Near the end of the first phalanx, each superficial flexor tendon is 

 split for the passage of the tendon of the deep flexor. Use: to flex the 

 second joint of each finger on the hand, the hand on the forearm, and the 

 forearm on the arm. 



Flexor digitorum profundus perforans arises from the superior three 

 fourths of the anterior surface of the ulna, and ends in four tendons, which 

 pass beneath the annular ligament, and are inserted into the phalanges, as 

 referred to Avhen speaking of the last muscle. Use: to bend the last 

 phalanx, and to co-operate with the superficial flexor in bending the other 

 phalanges and the wrist. 



Flexor pollicis longus arises from the fore part of the radius below its 

 tubercle and from the interosseous membrane, to within two inches of the 

 carpus. It is inserted into the middle of the last phalanx of the thumb, 

 which it serves to flex. 



Pronator quadratus is a small square muscle situated above the carpus, 

 and arising from the inferior fifth of the internal and anterior surface of the 

 ulna. It is inserted into the anterior part of the inferior fourth of the radius, 

 and serves to roll the radius over the ulna. 

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