17 



the artery gives off one or more branches to the flexor carpi externus, 

 anastemoses with the radialis anterior, and is continued along the antero- 

 external face of the radius, beneath the common digital extensor, to the 

 carpus where it anastemoses by a fine branch with the radialis anterior 

 and also commonly joins the rete carpi dorsalis. Near the proximal third 

 of the radius it gives off a small branch which runs along the extensor digi- 

 talis lateralis, suppHes twigs to this muscle and to the extensor carpi obliquus. 

 One or two centimeters distal to the interossea communis the A. radialis 

 posterior may give off another branch nearly as large as the A. interossea 

 communis. This second branch (in the present specimen) crosses at a 

 right angle the posterior face of the radius then tiu-ns towards the carpus 

 and is distributed by mmierous branches to the flexor perforans and flexor 

 perforatus. 



N. medianus (PL I, 32) arises from the 8th cervical and ist thoracic nerves. 

 Immediately below the A. axillaris the nerve usually receives a large branch 

 from the N. musculo-cutaneous thus forming with it a loop through which 

 the artery passes (PI. I) . Near the middle of the brachium the N. medianus 

 gives off a large branch which extends very obliquely beneath the biceps, 

 rarely sending a small filament to it, and divides into two branches (PL I, 

 34i 35) of which one is distributed to the brachialis; the other branch 

 winds very obliquely across the lateral face of the biceps, near the distal 

 end, to the antero-intemal face of the antebrachium where it divides into 

 two principal branches which accompany the two respective subcutaneous 

 veins, i.e. the cephalic and accessory veins, on the inner surface of the 

 antebrachium (PL I, 34') . The vein shoiild of course, be dissected along with 

 the nerves. The larger of the two subcutaneous branches of the nerve may 

 be traced to the middle of the metacarpus. The main trunk of the N. 

 medianus and the artery and vein radialis posterior, after crossing the 

 humero-radial joint, pass beneath the flexor carpi internus as already 

 demonstrated (PL I, 16). Note very carefully the relation of the nerve, 

 artery and vein to each other and to the posterior superficial pectoral 

 muscle and to the internal tuberosity of the radius. Median neurectomy 

 is performed in this region and also the pulse may here be readily felt. 

 A little before the N. medianus passes beneath the flexor carpi internus it 

 gives off two or three branches which are distributed as follows : One or 

 two branches, to the flexor carpi internus (PL I, 36) ; a much larger branch 

 which soon divides into two parts both of which are distributed to the 

 humeral portion of the flexor perforans (PL I, 37) ; and finally a small nerve 

 which also divides into two branches (PL I, 38) one of which extends into 

 the radio-ulnar arch and is distributed principally to the periosteum; the 



