self accordingly. It must have been through these means of fallacy that I have seen a most cautious and experienced operator deceived: he compressed the supposed artery, raised on the aneurism-needle, with his finger; the pulsation ceased, the ligature was tightened, and the severe pain occasioned by this step at once declared the error (which was in the course of a few moments remedied, and the operation ultimately and entirely successful); the convexity of the needle was doubtlessly resting on the artery, and compressed it upon the surface of the rib.
The application of a ligature to the subclavian artery on the tracheal side of the scaleni presents, perhaps, fewer merely mechanical difficulties than that just described, but involves a disturbance of more important organs, and requires perfect acquaintance with their anatomy. A separation of the sterno-cleido-mastoideus from its inferior attachment, and a division of the sterno-hyoid and sterno-thyroid muscles and of their sheaths (including that deep layer which lies beneath the sterno- thyroideus and immediately covers the vessel) will expose the artery.[1] The jugular vein is seen crossing it, close to the scalenus, at the outer part of the wound, behind which lies the phrenic nerve; at the inner part of the wound the bifurcation of the arteria innominata is brought into view, and the subclavian is seen diverging from the carotid. Between this point and the border of the jugular vein, from half an inch to an inch of artery intervenes, about midway on which the nervus vagus crosses at a right angle. If the nerve require to be drawn aside, this manœuvre must be executed with the extremest delicacy and gentleness;[2] and the operator should not fail to remember bis dangerous proximity to the pleura. The view of these parts is obscured by considerable venous hæmorrhage, which is here especially inconvenient, from the imperative necessity which exists for clearly seeing the artery and ascertaining the position of its branches before making any attempt to pass the needle. It is considered desirable to apply the ligature on the inner side of the vertebral branch, and as near to it as possible: yet, even under the most favourable circumstances, the adhesive actions at the seat of ligature must be seriously disturbed, both by the near direct stream of the carotid, and by the recurrent tides of the vertebral, mammary, and thyroid arteries. The single intance, in which I have seen this rare operation performed, was by my friend, Mr. Partridge, who brought to bear on its execution a perfect familiarity with every actual relation, and with every possible contingency; nor could it have been confidently undertaken, or safely conducted, by one of inferior resources. The case was in so far favourable, that the tumour was small, the position of parts unaltered, the arteries regular and free from disease, and the venous hæmorrhage not so troublesome as in many cases it certainly would be; the parts were clearly seen, and the artery secured without the least unnecessary disturbance of contiguous parts. Yet, I confess the impression, which I derived from this single instance of operation, and from frequent consideration of the parts in a great variety of subjects, to have been, that ligature of the arteria innominata would in all cases be as easy, and, in many, far easier to perform, would (by involving organs of less delicacy and importance, than those interested in the tracheal ligature of the subclavian) render hæmorrhage a less embarrassing obstacle, and would afford a better prospect of undisturbed adhesion in the artery. The steps, necessary for exposing the one, require so little modification, to become equally adapted for the other, that the surgeon might even be determined in his choice of either, by considerations developing themselves during the operation, by greater or smaller branchless extent of the subclavian artery, by the vertebral vein obscuring a large portion of this, or by other circumstances of the kind.
Although the arteria innominata cannot in anatomical strictness be considered as belonging to the neck, yet, in regard both of disease and of surgical operation, its affinity to that region is so close as to warrant its mention in this place. It rises from the convexity of the arch of the aorta, just as that main vessel, having terminated its ascent, inclines leftward. This point is in young subjects the highest level to which the aorta attains; but, as Cruveilhier notices, in old age the extreme part of the arch, which corresponds to the origin of the left subclavian artery, is higher. In early life, too, from incomplete development of the sternum, the convexity of the arch more nearly
- ↑ The description in the text is confined to the mode of tying the right subclavian artery, on which alone, as yet, the operation has been performed. As regards the left, the course of the vagus and phrenic nerves (which run parallel to the vessel), and of the thoracic duct (which almost surrounds it) would enormously multiply the risks of the operation; and the increasing depth and oblique descent of the artery, as traced from the scalenus inwardly, would, it is believed, defeat every endeavour to effect its adequate exposure. Should it be desirable to secure the vessel internally to its passage over the rib, the most available method would probably be that of tying it in the scalene space. This operation was performed in a single instance by Dupuytren in 1819 with success. The section of the scalenus anticus, if it were carefully executed, would be less perilous than on the right side, and might, under favourable circumstances, afford a sufficient space, between the branches of the artery and the aneurismal sac, to admit the safe application of a ligature. A complete division of the clavicular origin of the sterno-cleido-mastoideus would be required; and it would be necessary to obtain a distinct view of the phrenic nerve, before cutting the scalenus: the internal mammary artery might, as M. Malgaigne remarks, be injured even more readily than the nerve, if this incision were carelessly extended toward the median line.
- ↑ It is difficult, in reading the record, or in witnessing the progress of unsuccessful cases of operation at this part of the neck, to avoid believing that a neglect of cautious tenderness in managing the pneumogastric nerve, has tended to compromise the safety of the patient. No surgeon, who considers its vital importance to the functions and nutrition of the lung, can avoid viewing any unnecessary disturbance or rude traction of it as eminently perilous.
