SUBCLATIAN AETERIES. 100? 



outer part of the supra-scapular artery ; 10', transverse cervical "branches passing into 

 the deep surface of the trapezius ; 10", the posterior scapular artery, represented as 

 rising directly from the third part of the subclavian artery, and passing through the 

 axillary plexus of nerves and under the levator anguli scapulas ; 11, on the scalenus 

 anticus muscle, points to the inferior thyroid artery near the place where the ascending 

 muscular artery of the neck is given off; the phrenic nerve lies on the muscle to the 

 outside ; at i, the suprasternal twig of the suprascapular artery is shown. 



retdily felt in the wound, even while the parts covering it have still some 

 thickness. The sheath of the vessels is to be opened over the artery near 

 the trachea for thus the jugular vein is most easily avoided. This vein, 

 should it lie in front of the artery, as it sometimes does on the left side, and 

 especially at the lower part of the neck on that side, will be a source of 

 much difficulty in completing the operation, i. e., in passing the aneurism, 

 needle with the ligature about the artery. To surmount the difficulty much 

 caution is required. The operator will find it advantageous to have the 

 circulation in the vein (which in such operations becomes turgid and very 

 large) arrested at the upper end of the wound by means of an assistant's 

 finger. In most cases, if not in all, it is best to insert the aneurism needle 

 conveying the ligature on the outer side of the artery, for thus the vagus 

 nerve and the jugular vein will be most effectually avoided. 



SURGICAL ANATOMY OF THE SUBCLAVIAN ARTERIES. 



The subclavian artery is so deeply placed, its connections with important 

 parts are so intimate and varied, and the branches are so large in proportion 

 to the length of the trunk, that operations on this vessel present, in most 

 cases, considerable difficulties to the surgeon. But the difficulties, it will be 

 found, vary in different cases. 



The last division of the artery, that beyond the anterior scalenus muscle 

 (p. 366), is the part which is most favourably circumstanced for the applica- 

 tion of a ligature in the case in which such an operation is most frequently 

 called for, namely, aneurism affecting the artery in the axilla. This part is 

 preferable chiefly because the vessel is here nearest to the surface, and most 

 remote from the origin of the large branches. But, though the subclavian 

 artery appears to be easy of access above the clavicle while the parts are in 

 their natural position, it is to be remembered that, when an aneurism exists 

 in the axilla, the clavicle may be so much elevated in consequence of the 

 presence of the tumour, as to be placed in front of the vessel, or even above it. 

 In such circumstances, the artery lies at a great depth, and at the same time 

 the structures in front and behind it (the clavicle on the one hand, the vertebrae 

 with the muscles covering them on the other hand), cannot, in any degree, be 

 drawn asunder to facilitate the steps of the operation. It is when the outer 

 part of the clavicle is thus raised from the ordinary horizontal position, that 

 the height to which the artery arches above the bone becomes a point of im- 

 portance. In most cases it happens that a portion of the artery is a shorb 

 distance (about an inch) above the clavicle [plate 3] ; but occasionally, as 

 before mentioned (p. 367), it rises much higher [plate 20, fig. 3]; or it may 

 be lower than usual, lying close behind the bone [fig. 2]. If, in a case ren- 

 dering the operation necessary, the clavicle should be unusually raised, the 

 accessibility of the vessel in the neck will differ in these several conditions : 

 in one, the artery could be arrived at only by proceeding from above down- 

 wards behind the bone : in another, a part of it would still be higher than 

 the bone. This will serve, in part at least, to account for differences in the 

 time which the operation for tying the subclavian artery has occupied in the 



