186 



Muscles of the Upper Extremity. 



M. ext ossis 

 metac. poU: 



M. e 

 pollic. brev 



247. The Muscles of the 

 Hand 



248, The Muscles of the 

 Hand 



The Muscles of the Ball of the Thumb, Thcnar : 



M. abductor polUds brevis arises from the annular ligament (L'nj. 

 carp! transvcrswn), and is inserted into the radial border of the base of 

 the first phalanx of the thumb. 



.37". opponent polltcls s. flexor ossis metacarpi pollicis arises from the 

 annular ligament and is inserted into the radial border and head of 

 the metacarpal bone of the thumb. 



J/". flexor pollicis brer is arises by two heads : The superficial head 

 from the annular ligament, the deep head from the trapezium, os mag- 

 num, and unciform bone (Fig. 249): it is inserted into the base of the 

 first phalanx of the thumb. 



M. adductor pollic! $ arises by its broad base from the metacarpal 

 bone of the middle finger, and is inserted into the base of the first 

 phalanx of the thumb or the inner sesamoid bone of the first articu- 

 lation of the thumb. 



