596 



HUMAN ANATOMY. 



Fig. 578. 



Brachialis anticus — - j& 



Supinator 



I m ' 

 Insertion of pronator radii teres— ^fl' ,'|' j 



Flexor longus pollicis 



Pronator quadratus 



Tendon of flexor carpi radialis 



Abductor pollicis, cut 

 Opponens pollicis — ^- 



Bicipital 

 tubercle 

 of radius 



Flexor 

 profundus 

 digitorum 



Flexor 

 brevis pollicis 



Adductor pollicis, / 

 oblique portion-^- 



Flexor carpi 

 ulnaris 



Abductor 

 minimi digiti 



SS -'/ _ Anterior 

 annular 

 ligament 



Opponens 

 minimi digiti 

 Flexor brevis 

 minimi digiti 



Lumbri- 

 cales 



Adductor pollicis, 

 transverse portion 



Tendons 

 of flexor 

 sublimis 

 digitorum 



ulnar ; the fibres come from 

 the seventh and eighth cer- 

 vical and the first thoracic 

 nerves. 



Action. — The primary 

 action of the flexor pro- 

 fundus is to flex the ter- 

 minal phalanges of the 

 second, third, fourth, and 

 fifth fingers, but, continu- 

 ing its action, it also flexes 

 the remaining phalanges of 

 those digits and finally the 

 hand. 



Relations. — In the 

 arm the muscle is co\'ered 

 by the flexor sublimis digi- 

 torum and the flexor carpi 

 ulnaris, and has resting 

 upon its anterior surface 

 the ulnar vessels and the 

 median and ulnar nerves. 

 Posteriorly it is in relation 

 to the pronator quadratus 

 and the wrist-joint. In the 

 hand its tendons are cov- 

 ered by those of the flexor 

 subUmis and by the lum- 

 brical muscles ; they rest 

 upon the adductor pollicis 

 and interosseous muscles 

 and cross the deep palmar 

 arch. 



Variations. — The flexor 

 profundus frequently receives 

 additional slips from the flexor 

 sublimis and may be united to 

 the flexor longus pollicis. A 

 slip which has been termed 

 the accessorius ad flexoreni 

 profwiduni digitormn not in- 

 frequently occurs, arising from 

 the coronoid process of the 

 ulna and joining with one of 

 the tendons of the profundus. 

 The significance of the varia- 

 tions of the profundus will be 

 considered in connection with 

 those of the flexor longus pol- 



 



ncis. 



Dissection of muscles of forearm and hand, anterior surface ; superficial 

 muscles have been removed. 



2. Flexor Longus Pol- 

 licis (Fig. 578). 



Attachments. ^The 

 long flexor of the thumb 

 (m. flexor pollicis longus) 

 lies to the lateral side of 

 the flexor profundus digi- 

 torum and arises from the 

 anterior surface of the ra- 

 dius and the adjacent half 



