THE RADIAL REGION 



491 



The Opponens pollicis (m. opponens poll ids') (Figs. 368 and 369) is placed 

 beneath and partially to the outer side of the preceding. It arises from the 

 ridge on the trapezium and from the anterior annular ligament, passes downward 

 and outward, and is inserted into the whole length of the metacarpal bone of the 

 thumb on its radial side. 



Fir,. 368. Adductor pollicis, Opponens pollicis, and Pronator quadratus. (Testut.) 



Relations. By its superficial surface, with the Abductor and Flexor brevis pollicis. By its 

 deep surface, with the first metacarpal bone. By its inner border, with the Adductor obliquus 

 pollicis. 



The Flexor brevis pollicis (m. flexor pollicis brevis} (Fig. 369) consists of two 

 portions, superficial and deep. The superficial portion arises from the outer two- 

 thirds of the lower border of the anterior annular ligaments, and passes along 



