SUBCLAVIAN ARTERIES. 



825 



the thorax through the second intercostal 

 space, and in some other equally rare cases, 

 it has been seen to penetrate between the 

 sixth and seventh cervical transverse pro- 

 cesses. 



The superior intercostal artery passes 

 downwards in a tortuous manner into the 

 thorax, and gives off branches which run out- 

 wards and supply the two or three upper 

 intercostal spaces ; the artery of the right, 

 usually passes to one intercostal space lower 

 than that of the left side. The branch to the 

 first intercostal space is in general the small- 

 est. 



The trunk of the superior intercostal artery, 

 as it descends, has the following relations: in 

 front, it is covered by the pleura atid lung; 

 internal to it are placed the first dorsal gan- 

 glion of the sympathetic nerve, and the longus 

 colli muscle ; \vh\\st posteriorly, it corresponds 

 to the first dorsal spinal nerve (in its ascent 

 to join the last cervical), and to the neck of 

 the first rib. 



In addition to the branches furnished to the 

 intercostal spaces, and which are two or three 

 in number, the superior intercostal gives off 

 several small branches which enter the spinal 

 canal through its lateral foramina, and also a 

 branch which passes downwards and esta- 

 blishes a communication with the first aortic 

 intercostal artery. 



It has been already stated that the superior 

 intercostal and the deep cervical arteries most 

 frequently arise by a common trunk ; when 

 they arise separately, the left superior inter- 

 costal artery is generally derived from the 

 first stage of the corresponding subclavian 

 artery. 



Operative proceedings. It is not intended 

 in this place to enter into all the details con- 

 nected with the surgical relations of the sub- 

 clavian artery, since in the article which treats 

 of the surgical anatomy of the neck will be 

 found clearly described the modes of pro- 

 cedure to be adopted by the surgeon in the 

 operations for the ligature of this artery in 

 different parts of its course ; the following 

 few observations, which may be regarded as 

 supplemental to those just alluded to, naturally 

 follow the description which has been given 

 of the subclavian artery in the preceding 

 pages. 



First stage. When the relations of the 

 subclavian artery on the right side, internal to 

 the scaleni muscles, are carefully reviewed, the 

 inner half of this stage of the vessel will 

 appear to be the most eligible for the applica- 

 tion of the ligature, and the object of the 

 operator should be to secure the artery on 

 the cardiac side of its vertebral branch, as in 

 that situation the pleura is comparatively 

 little exposed to injury ; the jugular vein 

 should lie to the outside, and the vagus nerve 

 to the inside of the ligature, and any undue 

 disturbance of these parts, especially of the 

 latter, ought to be most sedulously avoided. 



The artery was tied, for the first time in 

 this situation, by Mr. Colles, in the year 1813. 

 In that instance, as in every subsequent one 



where the operation has been repeated, the 

 result has proved unfavourable ; nevertheless, 

 success has been so nearly attained in some of 

 these cases, that few will be found to agree 

 with Blandin in pronouncing this operation 

 " tout a fait irrationnelle ; " nor are we to view 

 with favour the alternative first suggested by 

 Mr. Shaw, and lately revived and recom- 

 mended to the profession in some recent 

 works on surgery, viz., to remove the arm at 

 the shoulder-joint, and to make pressure on 

 the aneurismal tumour. 



In the majority of the cases in which 

 hitherto the subclavian artery has been tied 

 internal to the scaleni, the cause of death was 

 referable to secondary haemorrhage ; the un- 

 avoidable proximity of the ligature on the one 

 hand to the heart, on the other to the aneur- 

 ismal sac, and the small extent of this part of 

 the subclavian artery to which a ligature can 

 be applied, without interfering with the colla- 

 teral branches, are probably the chief circum- 

 stances which determine this fatal accident. 

 If, in the desire to avoid the vertebral, thyroid, 

 and mammary branches, the ligature be ap- 

 plied too close to the mouth of the carotid 

 artery, the current of blood through the latter 

 vessel will then, with almost positive certainty, 

 disturb those sanative processes at the seat of 

 ligature, on which the ultimate success of the 

 operation depends ; and hence, doubtless, has 

 originated the proposal to secure at the 

 same time both branches of the innominata. 

 The incisions necessary to expose the one, 

 would amply suffice for the ligature of the 

 other ; the circulation through the head and 

 upper extremity might afterwards be carried 

 on without material injury, and the formation 

 of a coagulum, more lengthy than that afforded 

 by the operations hitherto performed, might 

 lead to a favourable result. This suggestion 

 is due to Dr. Hayden, and is mentioned in his 

 account of the case in which he tied this 

 artery in its first stage, so far back as the year 

 1835. 



The following brief particulars of a case 

 which lately came under the writer's notice, 

 may be adduced as furnishing an additional ar- 

 gument in favour of this proposal. A woman, 

 about 25 years of age, became the subject of 

 an aneurism, situated at the root of the neck, 

 which was regarded as originating from the 

 arteria innominata. The subclavian and 

 carotid arteries were tied at one and the same 

 time, on the principle of Brasdor: "On the 

 fourteenth day after the operation, the liga- 

 ture came away from the subclavian artery 

 without any haemorrhage, and every thing pro- 

 mised a favourable result, especially as the 

 ptilsatioH in the tumour had quite disappeared. 

 On the sixteenth' day, the patient, a woman of 

 violent temper, had a quarrel with the nurse, 

 when she jumped out of bed, seized a pillow 

 and some books, and threw them at her : 

 while making this exertion, haemorrhage set in 

 from the carotid." A renewal of the hae- 

 morrhage proved fatal. On examination it 

 appeared that " jinfrrt union had lakcu place 

 ivhcrc the //gat tire //ad been applied to the sub- 



