580 THE ARTERIES. 



over to the opposite side and the shoulder depressed as much as possible, the integument should 

 be drawn downward upon the clavicle, and an incision made through it, upon that bone, from 

 the anterior border of the Trapezius to the posterior border of the Sterno-mastoid, to which may 

 be added a short vertical incision meeting the preceding in its centre. The object in drawing 

 the skin downward is to avoid any risk of wounding the external jugular vein, for as it perforates 

 the deep fascia above the clavicle, it cannot be drawn downward with the skin. The cervical 

 fascia should be divided upon a director, and if the interval between the Trapezius and Sterno- 

 mastoid muscles be insufficient for the performance of the operation, a portion of one or both 

 may be divided. The external jugular vein will now be seen toward the inner side of the wound : 

 this and the suprascapular and transverse cervical veins, which terminate in it, should be held 

 aside. If the external jugular vein is at all in the way and exposed to injury, it should be tied 

 in two places and divided. The suprascapular artery should be avoided, and the Omo-hyoid 

 muscle held aside if necessary. In the space beneath this muscle careful search must be made 

 for the vessel : a deep la.yer of fascia and some connective tissue having been divided carefully, 

 the outer margin of the Scalenus anticus muscle must be felt for, and, the finger being guided by 

 it to the first rib, the pulsation of the subclavian artery will be felt as it passes over the rib. 

 The aneurism needle may then be passed around the vessel from above downward and inward, so as 

 to avoid including any of the branches of the brachial plexus. If the clavicle is so raised by the 

 tumor that the application of the ligature cannot be effected in this situation, the artery may be 

 tied above the first rib, or even behind the Scalenus anticus muscle ; the difficulties of the ope- 

 ration in such a case will be materially increased, on account of the greater depth of the artery 

 and the alteration in position of the surrounding parts. 



The second part of the subclavian artery, from being that portion which rises highest in 

 the neck, has been considered favorable for the application of the ligature when it is difficult to 

 tie the artery in the third part of its course. There are, however, many objections to the ope- 

 ration in this situation. It is necessary to divide the Scalenus anticus muscle, upon which lies 

 the phrenic nerve, and at the inner side of which is situated the internal jugular vein ; and a 

 wound of either of these structures might lead to the most dangerous consequences. Again, 

 the artery is in contact, below, with the pleura, which must also be avoided ; and, lastly, the 

 proximity of so many of its large branches arising internal to this point must be a still further 

 objection to the operation. In cases, however, where the sac of an axillary aneurism encroaches 

 on the neck, it may be necessary to divide the outer half or two-thirds of the Scalenus anticus 

 muscle, so as to place the ligature on the vessel at a greater distance from the sac. The opera- 

 tion is performed exactly in the same way as ligature of the third portion, until the Scalenus 

 anticus is exposed, when it is to be divided on a director (never to a greater extent than its outer 

 two-thirds), and it immediately retracts. The operation is therefore merely an extension of liga- 

 ture of the third portion of the vessel. 



In those cases of aneurism of the axillary or subclavian artery which encroach upon the 

 outer portion of the Scalenus muscle to such an extent that a ligature cannot be applied in that 

 situation, it may be deemed advisable, as a last resource, to tie the first portion of the subcla- 

 vian artery. On the left side this operation is almost impracticable ; the great depth of the 

 artery from the surface, its intimate relation with the pleura, and its close proximity to the 

 thoracic duct and to so many important veins and nerves, present a series of difficulties which it 

 is next to impossible to overcome. 1 On the right side the operation is practicable, and has been 

 performed, though never with success. The main objection to the operation in this situation is 

 the smallness of the interval which usually exists between the commencement of the vessel and 

 the origin of the nearest branch. The operation may be performed in the following manner : 

 The patient being placed on the table in the horizontal position with the neck extended, an incis- 

 ion should be made along the upper border of the inner part of the clavicle, and a second 

 along the inner border of the Sterno-mastoid, meeting the former at an angle. The sternal 

 attachment of the Sterno-mastoid may now be divided on a director and turned outward ; a few 

 small arteries and veins, and occasionally the anterior jugular, must be avoided, or, if necessary, 

 ligatured in two places and divided, and the Sterno-hyoid and Sterno-thyroid muscles divided in 

 the same manner as the preceding muscle. After tearing through the deep fascia with the finger- 

 nail, the internal jugular vein will be seen crossing the subclavian artery ; this should be pressed 

 aside and the artery secured by passing the needle from below upward, by which the pleura is 

 more effectually avoided. The exact position of the vagus nerve, the recurrent laryngeal, the 

 phrenic and sympathetic nerves should be remembered, and the ligature should be applied near 

 the origin of the vertebral, in order to afford as much room as possible for the formation of a 

 cpagulum between the ligature and the origin of the vessel. It should be remembered that the 

 right subclavian artery is occasionally deeply placed in the first part of its course when it arises 

 from the left side of the aortic arch, and passes in such cases behind the oesophagus or between 

 it and the trachea. 



Collateral Circulation. After ligature of the third part of the subclavian artery the col- 

 lateral circulation is mainly established by three sets of vessels, thus described in a dissection : 



'' ]. A posterior set, consisting of the suprascapular and posterior scapular branches of the 

 subclavian, anastomosing with the median branch from the subscapular from the axillary. 



'' "2. An internal set produced by the connection of the internal mammary on the one hand, 



1 The operation was, however, performed in New York by Dr. J. K. Rodgers, and the case is 

 related in A System of Surgery, edited by T. Holmes, 2d ed. vol. iii. pp. 620, etc. 



