Dissection of the Blood-Vessels and Nerves of 

 the Arm or Pectoral Limb 



Cut the skin along the median Hne from the xiphoid cartilage to a point 

 15 or 20 cm. cephalad of the prestemtttn; also cut at a right angle to this 

 along the middle of the proximal half of the antebrachium and reflect the 

 skin from the pectoral muscles. Note the large vein (V. cephalica) and the 

 small artery lying in the groove formed by the anterior superficial pectoral 

 muscle and the adjoining border of the M. mastoido-humeralis. Transect 

 the two superficial pectorals close to their sternal attachments. Now 

 dissect up the cervical panniculus, transect it a short distance from its 

 attachment to the stemiim and turn it aside. Beneath this portion 

 of the panniculus is a mass of fatty tissue in which are nimierous lymph 

 nodules — the Prescapular or superficial cervercal lymph gland. The full 

 extent of this gland may be seen when the M. mastoido-humeralis is turned 

 aside. Transect the mastoido-humeralis a little above (cephalad) the 

 point of the shoulder and turn it aside sufficiently to expose the underlying 

 prescapular portion of the anterior deep pectoral muscle and the prescapular 

 lymph gland. Do not disturb unnecessarily the gland for beneath it 

 are an artery and vein of some surgical importance. Trace the large 

 Vein (V. cephalica) and the small artery (a branch of the A. cervicalis 

 inferior) that cross the anterior deep pectoral muscle in the groove between 

 this muscle and the mastoido-htunerahs, in so far as the vessels are at 

 present accessible. Ligate and cut the vessels. Abduct the arm somewhat 

 and identify the two deep pectoral muscles . Transect the latter muscles close 

 to their attachment to the stemimi. Abduct the arm a little and dissect 

 between the deep pectoral muscles and the thoracic wall until the large A. 

 and V. Axillaris are exposed. Carefully clean up the V. Axillaris noting 

 meantime the lymph glands, Posterior cervical or prepectoral, that lie 

 just cephalad or anterior to the V. Axillaris. Cut the vein in order clearly 

 to expose the A. Axillaris which Hes immediately dorsal to it. Clean up 

 the A. Axillaris taking care not to cut any of its branches or the nerves that 

 cross the ventral surface of the artery a short distance (4 to 6 cm.) from the 

 first rib. Cut the artery close to the rib. Occasionally a large vein Hes 

 just anterior to the A. Axillaris; if so, this also should be cut. 



A. cervicalis inferior arises from the axillaris nearly opposite the first rib. 

 Near the ventral border of the M. scalenus it divides into two nearly equal 

 branches— a ventral and a dorsal branch. The ventral branch crosses 



