BRACHIAL ARTERY. BRANCHES. 



383 



greater part of its length with the biceps, the inner border of one or both 

 muscles sometimes slightly overlapping it. 



Relation to Veins. Venae comites are in close contact with the brachial 

 artery, short transverse branches of communication passing from one to 

 another, so as at many points to encircle it. Superficial to the aponeurosis, 

 the basilic vein is placed over or to the inner side of the artery in the lower 

 half or more, or in the whole length of its course, according to the level at 

 which the vein dips down to join the venae comites ; and at the bend of the 

 elbow the median basilic vein crosses over the artery, the aponeurotic inser- 

 tion of the biceps lying between them. 



Relation to Nerves. The median nerve descends in contact with the 

 artery, lying on its outer side at the axilla, directly in front of it below the 

 middle of the arm, and on the inner side at the elbow. Of the large 

 branches of the brachial plexus which are closely connected with the axillary 

 artery, none continue in the immediate neighbourhood of the brachial 

 artery along the arm, except the median. The external cutaneous and 

 circumflex separate at once from the vessel in the axilla, the musculo-spiral 

 soon turns backwards in the musculo-spiral groove, and the internal 

 cutaneous and ulnar nerves descend vertically on the iuner side of the 

 limb. 



Fig. 269. 



Fig. 269. SUPERFICIAL DISSECTION OP THE 

 BLOOD-VESSELS AT THE BEND OP THE ARM 

 (from R. Quain). ^ 



a, two branches of the internal cutaneous 

 nerve ; a', a', the descending twigs of the same 

 nerve ; 6, placed over the biceps near its inser- 

 tion and close to the external cutaneous nerve ; 

 &', anterior twigs of the same nerve accompany- 

 ing the median vein ; 1, placed on the fascia of 

 the arm near the bend of the arm, above the 

 place where it has been opened to show the lower 

 part of the brachial artery with its vena? comites, 

 of which one is entire, marked 2, and the other 

 has been divided ; + , is placed between this and 

 the median nerve ; 3, basilic vein ; 3', 3', ulnar 

 veins ; 4, cephalic vein ; 4', radial vein ; 5, 5, 

 median vein ; 3', 5, median basilic vein ; 4', 5, 

 median cephalic vein. 



BRANCHES. The brachial artery gives 

 some unnamed branches, which are di- 

 rected outwards and backwards to the 

 muscles in its immediate neighbour- 

 hood, viz. , to the coraco-brachialis, biceps, 

 ,-md brachialis anticus. The following 

 branches, which incline inwards, have 

 received names, and require descrip- 

 tion. 



(a) The superior profunda artery 

 (collateralis magna) arises from the inner 



and back part of the brachial, just below tha border of the teres major, 

 and inclines backwards, to reach the interval between the second and 

 third heads of the triceps muscle. Accompanied by the musculo-spiral 

 nerve, it winds round the back of the huinerus, in the spiral groove, under 



