170 DR. R. W. SHUFELDT ON [-^Pl"- 1> 



in each case into the base of the second, third, and fourth metacar[)al 

 bones. Just beyond its origin this muscle is very thick and fleshy, and 

 in this locahty fuses to some little extent with the supinator lougus, 

 while at its insertion a thin tendinous expansion more or less unites 

 its slips of division, and spreads out over the back of the carpus. 



3S. Extensor carpi radialis. — Running parallel with the extensor 

 digitorutn longus, this muscle likewise arises, tendinous, from the 

 external condyle of the humerus, and, as it approaches the carpus, it 

 forms a slender tendon which inserts itself into the os carpi radiate. 



This muscle has not more than a quarter the bulk of tlie extensor 

 digitorum longus, with which it is quite intimately connected along 

 its radial border. 



39. Extensor digitorum brevis. — Superficially, on the back of the 

 manus, we observe a divided set of muscles, which constitute the 

 short extensors of the phalanges. Five-parted, but each slip more 

 or less distinct, the extensor digitorum brevis arises from the dorsal 

 aspect of the five metacarpal bones at their proximal extremities, and 

 from the ossicles of the first row of the carpus. These slips are 

 fleshy over the back of the hand, but become tendinous, each one 

 at the bases of the digits, and a tendon runs along the back of each 

 phalanx to the base of the ungual joint, where it is, in each case, 

 inserted. 



Proximally, these muscular slips are imbricated, while distally 

 their tendons, as they pass over each phalangeal joint in the fingers, 

 send down lateral tendinous slips on either side, which attach to the 

 sides of the heads of the finger-bones. 



40. Extensor carpi ulnaris. — Springing from the postero-exterual 

 aspect of the external condyle of the humerus, in common with the 



Jlexor carpi ulnaris, by a strong tendon, this muscle passes down 

 the side of the forearm ; when opposite the radial side of the wrist 

 it develo|is a strong teudon which, passing between the muscles of 

 the hand on that side, finally inserts itself into the proximal end 

 of the fifth metacarpal, upon its external surface. 



41. TJlno-metacarpalis pollicis.- — I propose this name for the 

 present muscle in lieu of the " Vlno-pollicialis dorsalis s. Ahdtcctor 

 pollicis longus " of Fiirhriuger, or even the " M. uluo-metacurpiulis 

 Z" of Hoffmann. It is the Abductor pollicis longus of Stanuius, 

 the Extensor ossis metacarpi pollicis of Mivart and Sanders. It 

 arises from the dorsal aspect of the lower third of the forearm ; 

 springing from the upper surface of the shaft of the ulna, it passes 

 obliquely across the carpus, to finally develop a strong little tendon 

 which is inserted into the proximal end of the poUex metacarpal, 

 upon its dorsal side. 



42. The Jlexor carpi idnaris arises by two heads — one from 

 the posterior surface of the radial condyle of the humerus, and the 

 other from the side of the proximal extremity of the idna and from 

 the olecranon process of that bone. These are at first strong tendons, 

 but soon become carneous and forming aflat, powerful muscle running 

 dow n the outer side of the forearm, which again becomes tendinous 

 at the wrist, to finally insert itself into the pisiform bone, upon the 



