22S MARSHALL— A STUDY OF THE 



[June 19, 



this region. The distal portion of this tendon with that of the m. 

 flexor digitorum is held in place by a delicate ligament extending 

 from the distant ventral border of the radius to the ventral projec- 

 tion on the third metacarpal above the os carpi ulnare. 



11. M. ulni metacarpalis dorsalis (UI. met. d., PI. V, Fig. 24), 

 arises by a short strong tendon from the dorsal distal end of the 

 ulna at the base of the external condyle. The tendon bends around 

 the condyle to its posterior border where it swells rapidly into a 

 thick muscle. The greater part of the muscle is inserted fleshily 

 on the posterior border of the fourth metacarpal. A small part of 

 the muscle terminates distally in a broad, flat tendon which fuses 

 with those that go to the quills. 



12. M. extensor metacarpi ulnaris {radialis ?) (£. met. ul. r., 

 PI. V, Figs. 19, 20, 22, 24). The origin of this muscle is the most 

 proximal of all that come from the distal end of the humerus. It 

 arises by two heads, one tendinous, the other fleshy, from the ante- 

 rior surface of the humerus superior to the external condyle and 

 above the upper insertion of the m. propatagialis brevis, the tendin- 

 ous head being somewhat dorsal. At about 7 mm. from its origin 

 the tendon passes over into a fusiform muscle. At the same point 

 is given off a tendinous, sheath which fuses with the tendon of 

 the propatagialis brevis, above the first bifurcation of that ten- 

 don. This muscle is smaller and lies dorsal to the one of fleshy 

 origin. About the mid-point of the radius the two muscles unite 

 to form a strong, flat tendon which passes over the end of the radius, 

 across the os radiale, and is inserted on the apex of the os magnum. 



13. M. extensor metacarpi ulnaris (E. met. ?(/., PI. V, Fig. 22). 

 This muscle springs from the external condyle of the humerus close 

 beside the m. extensor digitorum communis. At its origin it is held 

 in place by a delicate ligament. It finds attachment on the pos- 

 terior surface of the third metacarpal about one third the distance 

 from its proximal end. 



14. M. flexor digitorum sublimis (F. dig. s., PI. V, Fig. 24). 

 This is the central superficial muscle of the inner forearm. It 

 arises by a strong, flat tendon from the internal condyle of the 

 humerus. The muscle bundle runs parallel to the ulna, and on the 

 inner side of the flexor carpi ulnaris for about two thirds the length 

 of the ulna, and there separates into two tendons. The posterior 

 tendon passes over the os ulnare, bends under the tendon of the m. 



