CUTANEOUS VEINS. 249 



On the outer side of the arm, about its middle, two external cutaneous 

 branches of the musculo-spiral are to be sought. In the outer bicipital 

 groove, in front of the elbow or rather below it, the cutaneous part of the 

 musculo-cutaneous nerve will be recognized. 



On the inner part of the limb the nerves to the surface are more nume- 

 rous. Taking the basilic vein as a guide, the internal, cutaneous nerve of 

 the forearm will be found by its side, about the middle of the arm ; and 

 rather external to this nerve is a small cutaneous offset from it, which 

 pierces the fascia higher up. Scrape through the fat behind the internal 

 cutaneous, in the lower third of the arm, for the small nerve of Wrisberg; 

 and in the upper third, seek the small nerves which have been already 

 met with in the dissection of the axilla, viz., the intercosto-humeral, and 

 the internal cutaneous of the musculo-spiral. 



Superficial fascia. The subcutaneous fatty layer forms a continuous 

 investment for the limb, but it is thicker in front of the elbow than in the 

 other parts of the arm. In that spot it incloses the superficial vessels and 

 the lymphatics. 



CUTANEOUS VEINS. The position and the connections- of the superficial 

 veins in front of the elbow are to be attentively noted by the dissector, 

 because the operation of venesection is practised in one of them. 



The median vein of the forearm (fig. 76, 2 ), divides into two branches, 

 internal and external, rather below the bend of the elbow ; at its point of 

 division it is joined by an offset from a deep vein. The internal branch 

 (median basilic) crosses to the inner border of the biceps, and unites with 

 the ulnar veins ( 3 ) to form the basilic vein of the inner side of the arm. 

 The external branch (median cephalic) is usually longer than the other, 

 and by its junction with the radial vein ( 7 ) gives rise to the cephalic vein 

 of the arm. 



The connections of the two veins into which the median bifurcates, are 

 described below : 



The median cephalic vein (fig. 7G) is directed obliquely, and lies over 

 the hollow between the biceps and the outer mass of muscles of the fore- 

 arm. Beneath it is the trunk of the musculo-cutaneous nerve ; and over 

 it some small offsets from the nerve are directed. This vein is altogether 

 removed from the brachial artery, and is generally smaller than the me- 

 dian basilic vein. If opened with a lancet, it does not generally yield 

 much blood, in consequence of its position in a hollow between muscles 

 rendering compression of it very uncertain and difficult. 



The median basilic vein (fig. 76, ') is more horizontal in direction than 

 the preceding, and crosses the brachial artery. It is larger thaji the cor- 

 responding vein of the outer side of the arm, and is firmly supported by 

 the underlying fascia the aponeurosis of the arm, strengthened by fibres 

 from the biceps tendon, intervening between it and the brachial vessels. 

 Branches of the internal cutaneous nerve lie beneath it, and some twigs 

 of the same nerve are placed over it. 



The median basilic is the vein on which the operation of blood-letting 

 is commonly performed. It is selected in consequence of its usually larger 

 size, and more superficial position, and of the ease with which it may be 

 compressed ; but from its close proximity to the brachial vessels, the spot 

 to be opened should not be immediately over the trunk of the artery. 



The basilic vein (fig. 76, 5 ), commencing as before said, ascends near 

 the inner border of the biceps muscle to the middle of the arm, where it 



