394 THE AXILLARY ARTERY. 



On the right side, though deeply placed and closely connected with important 

 parts, the first division of the subclavian artery may be tied without extreme 

 difficulty. But inasmuch as the length of the vessel, between its three large 

 branches on the one hand, and the common carotid on the other, ordinarily 

 measiires no more than an inch, and often less ; the success of the operation is 

 somewhat doubtful. 



In order to place a ligature on the portion of the right subclavian artery here 

 referred to, it is necessary to divide by horizontal incisions the three muscles 

 which cover it, together with the layers of fascia between and beneath them. 

 "While the muscles are being divided, a branch of the suprascapular artery will 

 probably require to be secured. In the farther steps of the operation, the exact 

 relations of the artery to the internal jugular vein, the vagus nerve, and the 

 plem-a, are to be well kept in view. 



It is to be remembered also that the right subclavian artery is occasionally 

 somewhat more deeply placed than usual in the fii\st part of its course ; as in 

 certain cases of variation, when it springs from the back part of the aortic arch, 

 or, more frequently, when it merely separates from the innominate behind the 

 carotid. 



AXILLARY ARTERY. 



The axillary artery is that part of the artery of the upper limb which 

 extends from the outer border of the first rib to the lower margin of the- 

 tendons of the latissimus dorsi and teres major muscles. In this 

 course it passes through the axilla, and its direction varies with the 

 position of the limb, being curved downwards, or upwards, or being 

 straight, according as the arm hangs by the side, or is elevated, or 

 extended. 



In front, the axillary artery is covered by the pectoralis major muscle,, 

 behind which it is crossed by the pectoralis minor. It may be con- 

 veniently divided into three parts : the first part lying internal to the 

 pectoralis minor muscle, the second part being behind that muscle, and 

 the third part beyond it. 



In the first part of its course the vessel has the first intercostal 

 space, and the first slip of the serratus magnus muscle with the posterior 

 thoracic nerve on its inner side, and is covered by the costo-coracoid 

 membrane, which, attached above to the clavicle, is continued below 

 into a common sheath investing the artery and vein, which is completed 

 behind by a prolongation of the deep cervical fascia. In this part of 

 its course the artery is placed with the trunks of the brachial plexus 

 above and behind it, and the axillary vein in front of it and somewhat 

 nearer the thorax : it is also crossed by the cephalic and acromio- 

 thoracic veins as they dip down to terminate in the axillary vein. 



In the second part of its course, behind the pectoralis minor, the 

 axillary artery is completely surrounded by the trunks of the brachial 

 plexus, and is crossed in front by one of the roots of the median nerve :. 

 the vein is on the thoracic side of the artery, separated from it by 

 nerves. 



In the ihird part of its course, beyond the pectoralis minor, the 

 axillary artery rests on the subscapular muscle and the insertions of the 

 latissimus dorsi and teres major, while to the outer side is the coraco- 

 brachialis muscle. The axillary vein is still on the thoracic side, but 

 sometimes the venre comites, by whose union it is formed, are con- 

 tinued up to this level, one on each side of the artery. The main 

 branches resulting from the division of the brachial plexus of nerves 

 are disposed behind and on each side of this ]iart of the artery, as- 



