SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 353 



membrane associated with both bones. For purposes of convenience call the 

 extensor ossis metacarpi pollicis the strong muscle. Then say : 



1. The long muscle (the extensor longus pollicis) arises from the posterior 

 surface of the long bone (the ulna) and the interosseous membrane. 



2. The short muscle (the extensor brevis pollicis) arises from the posterior 



Articular branch of superior 

 projundu 



Braehialis anticus 

 Supinator longus, cut 



Common extensor tendon 



Extensor carpi radialis longior 

 and brevior 



Supinator brevis 



Posterior inlerosseous artery 



Extensor osais metacarpi pollicis 

 Supiuator longus, cut 



Extensor primi iuternodii polUcis 



Posterior annular ligament 



Extensor carpi radialis longior 



Radial artery 



Dorsal is pollicis artery 



Extensor secundi internodii 



pollicis 



First dorsal interosseous muscle 



Dorsalis indicis artery 



Pnnceps pollicis artery 



Dorsal digital artery 



Triceps 



Rete over olecranon 

 Inlerosseous recurrent artery 



Ancoueus, cut 



Extensor carpi ulnaris 

 Flexor carpi ulnaris 



Origin of extensor secundi and 

 indicator 



Posterior branch of anterior inlerosseous 



artery 

 Interosseous membrane 



Posterior ulnar carpal artery 

 Extensor carpi radialis brevior 

 Posterior radial carpal artery 



Third dorsal interosseous artery 

 Second dorsal inlerosseous artery 

 Melacarpal or first dorsal interosseous 

 artery 



\J 



Vt_>' 



FIG. 247. THE BACK OF THE FOREARM, WITH THE POSTERIOR INTEROSSEOUS ARTERY AND 



BRANCHES OF THE RADIAL AT THE BACK OF THE WRIST. 



(From a dissection in the Hunterian Museum.) 



surface of the short bone (the radius) and the interosseous membrane. Insertion 

 into the base of the first phalanx. 



3. The strong muscle (the extensor ossis metacarpi pollicis) arises from the 

 posterior surfaces of both the long and short bones (ulna and radius) and the 

 interosseous membrane. Insertion into base of metacarpal bone. 



