SUPERFICIAL VEINS OF ARM. 41 



cutaneous part of the rnusculo-nitaneous nerve will be recognised. 

 See fig. 16. 



On the inner part of the limb the nerves to the surface are more a " d i nn 

 numerous. Taking the basilic vein as a guide, the internal cuta- u m b. 

 neous nerve of the forearm will be found by its side, about the 

 middle of the arm ; and a little external to this nerve is a small 

 cutaneous offset from it, which pierces the fascia higher up. 

 Finally follow down the small nerves which have been already met 

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

 ksst-r internal cutaneous (nerve of Wrisberg), and the internal 

 cutaneous of the musculo-spiral. 



ficial fascia. The subcutaneous fatty layer forms a con- Superficial 

 tinuous investment for the limb, but it is thicker in front of the fat ' 

 elbow than in the other parts of the arm. At that spot it encloses 

 the superficial vessels and lymphatics. 



CUTANEOUS VEINS. The position and relations of the veins in Superficial 

 front of the elbow are to be attentively noted by the dissector, vems - 

 because the operation of venesection is practised on one of them 

 (fig. 16). 



The MEDIAN VEIN of the forearm divides into two branches, Median 

 internal and external, rather below the bend of the elbow ; ^ em ' 

 and at its point of division it is joined by an offset from a deep two 

 vein. The internal branch (median-basilic) crosses to the inner br 

 border of the biceps, and unites with the ulnar veins 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 gives rise to the cephalic vein of 

 the arm. 



The MEDIAN-CEPHALIC VEIN is directed obliquely, and lies over median- 

 the hollow between the biceps and the outer mass of muscles of the ce P hahc > 

 forearm ; beneath it is the trunk of the musculo-cutaneous nerve. 

 This vein is altogether removed from the brachial artery, and is 

 usually smaller than the median-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 is more transverse in direction, and median- 

 larger than the preceding ; and it crosses the brachial artery. It basilic - 

 is firmly supported by the underlying fascia, the aponeurosis of 

 the arm, strengthened by an offset from the biceps tendon, inter- 

 vening 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- Venesection, 

 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, commencing as before said, ascends near Basilic vein. 



