A dense process of cervical fascia (just becoming thoracic) now covers the vessel, binding it on the right side to the right innominate vein, and on the left maintaining the relation of the innominate artery to the trachea. The inferior thyroid veins lie on this fascia, and must be drawn aside, not cut. The fascia is then to be scraped through very cautiously, exposing the root of the right carotid, which, being traced downwards, will lead to the innominate. The following parts lie in close relation to the vessel at the point of ligature, and must be avoided:—1. The left innominate vein crosses the artery in front from left to right, and must be drawn down. 2. The right innominate vein and right pneumogastric are in close contact with the artery on the right side; to avoid them the aneurism-needle must be entered on the outside (right of the vessel). 3. The apex of the right pleura and the trachea are in close contact behind, requiring the point of the needle to be kept close to the artery in bringing the thread round.

It might have been expected that the sudden arrest of so large a proportion of the vascular supply of the body, so very near the heart, would cause serious, or even fatal symptoms; this, however, is not the case, no serious inconvenience of this sort being experienced; yet hitherto every case has proved fatal, either from secondary hæmorrhage or inflammation of lungs and pleura.

In fifteen well-authenticated, and in three more doubtful cases, the ligature has been applied; all of these died at periods varying from twelve hours (as in Hutin's case), to forty-two days as in Thomson's, and sixty-seven days (Graefe's).¹¹

A successful case of ligature of the innominate along with the right carotid and (after secondary hæmorrhage) the right vertebral, in a mulatto aged thirty-two, for a subclavian aneurism, has been put on record by Dr. Smyth of New Orleans, in the American Journal of Medical Science for July 1866.

And here we may also note that Mr. Heath has lately treated a case of innominate aneurism by simultaneous ligature of the third part of the subclavian and the carotid. Both ligatures separated on the eighteenth day, and the tumour was much smaller some months afterwards.¹²

Mr. R. Barwell has reported several most interesting cases in which simultaneous ligature of carotid and subclavian have proved of marked benefit in aortic as well as in innominate aneurisms.¹³

In four cases the operation was attempted, but the operators had to desist before the application of the ligature, in consequence of the diseased state of the arterial coats. Of these, three died, and one (Professor Porter's of Dublin) case recovered, the patient leaving the hospital with the aneurism nearly consolidated.

Dr. Peixotto of Portugal applied a precautionary ligature to the innominate in a case where secondary hæmorrhage occurred from the carotid. The ligature was not tightened beyond what was necessary merely to cause flattening of the vessel. The patient made a good recovery.

Professor George Porter of Dublin records an interesting case of subclavian aneurism, in which, after failing to close the axillary artery by acupressure, he applied L'Estrange's compressor to the innominate itself for three days, with temporary benefit. The patient eventually died of hæmorrhage.¹⁴

For a very full and interesting account of ligatures of vessels in root of neck we may refer to vol. iii. of the 1883 edition of Holmes' Surgery, pp. 119-122.

Ligature of Common Carotid.—Though the anatomical relations of the right and left carotid are different at their origin, they so precisely resemble each other in the whole of that part of their course which is at all amenable to surgical treatment, that one description will suffice for both, and the necessary anatomy will be brought out quite sufficiently in the description of each operation.

From its giving off no collateral branches, the common carotid artery may be tied at any part of its course.

It has been tied successfully at the distance of only three-quarters, or, in one case by Porter, hardly to be imitated, one-eighth of an inch from the innominate, and up to an equal distance from its bifurcation. In choosing the part of the vessel for operation, the operator must be guided by the position of the aneurism, if on the vessel itself, but if the aneurism be distant, as in scalp or orbit, he need have regard to position simply as facilitating the operation.

The easiest position in which to apply the ligature is just above the omohyoid muscle, the vessel being there superficial.

Ligature above Omohyoid.—Using the anterior border of the sterno-mastoid as a guide, but leaving it gradually above to a little nearer the mesial line, an incision (Plate IV. fig. 1), varying in length according to the depth of fat and cellular tissue in the neck, but with its central point opposite the upper border of the cricoid cartilage, must be made through skin, platysma, and superficial fascia. While making the incision the head should be held back, and the face slightly turned to the opposite side; the parts being now relaxed by position, the edges of the wound must be held apart by blunt hooks or copper spatulæ, and the deep fascia carefully divided over the vessel, which will be recognised by the pulsation. It may be noted here that even in thin subjects the sterno-mastoid edge invariably overlaps the vessel, though in many anatomical diagrams it would appear to be in part subcutaneous.

The descendens noni may possibly be seen, but this is by no means invariably the case, crossing the sheath of the vessel very gradually from without inwards in its progress down the neck. It must be carefully displaced outwards.

The sheath of the vessel is then to be cautiously opened to the extent of about half an inch. The internal jugular vein, possibly much distended, may overlap the artery on its outer side, and will require to be pressed, emptied, and held out of the way. A small portion of the artery being thoroughly separated from the sheath, the aneurism-needle must be passed from without inwards to avoid the vein, and keep as close to the artery as possible to avoid the vagus.

The tendon of the omohyoid muscle, or, in muscular subjects, a portion of its anterior fleshy belly, may be seen crossing the vessel from above downwards and outwards at the lower angle of the wound.

An enlarged lymphatic gland has occasionally given much trouble, by being mistaken for the vessel and cleaned, while the ligature has even been placed on a carefully isolated fasciculus of muscular fibres.

Ligature of Carotid below the Omohyoid.—An incision in precisely the same direction as the former, but at a slightly lower level, is required, but the dissection is rather more difficult. The edge of the sterno-mastoid when exposed must be drawn outwards; the sterno-hyoid and thyroid inwards; the omohyoid upwards; the sheath opened, and the descendens noni or its branches drawn to the tracheal side. The jugular vein and vagus are both at the outer side, and must be avoided, while the inferior thyroid artery and sympathetic nerve both lie behind the vessel, and may be included in the ligature if care be not taken.

Varieties.—Sedillot's Operation.—To secure the artery still lower in the neck: An incision two and a half inches long, from the inner end of the clavicle obliquely upwards and outwards in the interval between the sternal and clavicular attachments of the sterno-mastoid; this divides the superficial textures; the two portions of muscle must then be drawn apart. The internal jugular vein lies in the interval, and must be drawn to the outside before the artery can be seen at all, and it is this that makes this operation very difficult and dangerous, especially on the left side, where the vein is close to the artery, and probably even crossing it from left to right. The thoracic duct is behind.

Malgaigne's modification of the above is an improvement: to expose the external attachment of the muscle, to cut it through and turn it to the outside, as in the operation for ligature of the innominate, then to divide or pull inwards sterno-hyoid and sterno-thyroid, thus exposing the sheath. The needle must be passed from without inwards.

Results.—Pilz has collected 600 cases, of which 43.16 per cent. died. The united tables of Norris and Wood give 188 cases, with a mortality of sixty, or nearly one in three. These tables include cases in which the vessel was tied for wounds, and as a preparatory step in the operation of removal of tumours of the jaw, etc. Later statistics give a very much lessened mortality, due chiefly to the use of animal ligatures.

Of thirty-one cases in which it was tied for pulsating tumours of the orbit, only two died from the operation.¹⁵ Rivington's statistics to a later date give forty-six cases on forty-four patients with six deaths.

Both carotids have been tied in the same patient twenty-five times, at intervals of less than a year; and it is a very remarkable fact that only five of these fifty ligatures proved fatal,—two in which both were tied on the same day, and three in which the operation was performed to arrest hæmorrhage from malignant disease of the face and jaws—from gunshot wound,—and from syphilitic ulceration.

The external carotid, and also most of its principal branches, have been tied for aneurisms, wounds, goitres, enlargement of the tongue, vascular tumours on occiput and other lesions; also as a first stage in the operation of extirpation of the upper jaw, for the purpose of preventing hæmorrhage. However, such operations are rare, and will probably become rarer still, and it is hardly necessary to describe the operations on each seriatim.

Aneurism of the external carotid or branches are rare; if idiopathic, ligature of the common carotid will be found at once easier, not more dangerous, and more effectual than ligature of the branch; if traumatic, the aneurism itself should be attacked, and the bleeding point secured by a double ligature. Wounds are common enough, but if accessible at all, the injured vessel should be tied at the bleeding point; if inaccessible (and under this head we may include wounds of the internal carotid), the common carotid must be tied.

No one would think of trying the superior thyroids for goitre, unless they were so manifestly enlarged, tortuous, and pulsating, as to render the operation so simple (from their superficial position) as to require no special directions; besides this, the cases in which it has been already done have given very little encouragement to repeat it.

As cases may occur in which any diminution of the cerebral supply is contra-indicated, and thus the more difficult ligature of the external carotid may be preferred to the more simple operation on the common trunk, and as the lingual may require ligature near its root, in consequence of obstinate hæmorrhage from the tongue, short directions are given for the performance of both these operations.

1. Ligature of External Carotid.—Head in same position as for the common carotid. A straight incision parallel with the anterior edge of sterno-mastoid, but about half an inch in front of it, must begin almost at angle of jaw, and extend downwards nearly to the level of the thyroid cartilage. Cautiously divide skin, platysma, and fascia; the lower end of the parotid must be pulled upwards, and the veins, which are numerous, cautiously separated. The anterior border of the sterno-mastoid must be pulled backwards, and the digastric and stylo-hyoid forwards and inwards. The superior laryngeal nerve which lies behind the vessel must be avoided.

2. Ligature of Lingual.—To secure this vessel either before it becomes concealed by the hyo-glossus, or after it is under the muscle, a curved incision is necessary, following the line of the hyoid bone, and especially of its greater cornu, but a line or two above its upper border. After the skin and platysma are divided, the posterior belly of the digastric must be recognised, which again will guide to the posterior edge of the hyo-glossus. The edge of the sub-maxillary gland may very probably require to be raised out of the way. The artery can then be secured, either before it dips under the hyo-glossus muscle, or after it has done so, by the division of a few of its fibres on a director. Care is needed to avoid injury of the hypo-glossal nerve, which lies above the muscle.

The internal carotid artery occasionally, but very rarely, is the subject of aneurism. It may, like any other artery, be wounded, especially from the fauces. The treatment of either of these lesions is ligature of the common carotid itself, in preference to ligature of the internal carotid. Guthrie's operation for securing the bleeding internal carotid at the injured spot, by dividing and turning up the ramus of the lower jaw, has never been performed in the living body, and is so difficult, dangerous, and unnecessary, as not to merit description.

Ligature of Subclavian.—Note.—In consequence of the difference in the origin, and variety in the anatomical relations of the right and left subclavian arteries, in so far at least as their first stage is concerned, it is necessary to give a very brief separate account of each.

Right Subclavian.—The innominate artery divides into the right subclavian and right carotid exactly behind the sterno-clavicular articulation. The right subclavian extends from this point in an arched form across the neck, between the scalene muscles, over the apex of the pleura, till, passing under cover of the clavicle, it changes its name to axillary at the lower end of the first rib. For convenience of description, the artery is divided into three parts, which have very various anatomical relations, and differ from each other much in their amenability to surgical treatment by ligature. The anterior scalenus muscle defines the three parts, the first extending to the inner border of the muscle, the second being concealed by the muscle, and the third reaching from its outer border to the lower border of the first rib.

Branches of the Subclavian.—While the deep relations of pleura, veins, and nerves can be noticed under the head of each operation in detail, one anatomical point must never be forgotten as influencing very much the success of all surgical interference with the subclavian arteries—i.e. the branches given off. To give any chance of success in the application of a ligature to such a large vessel, so near the heart, a large portion of artery free from branches is required, that the clot may be long, firm, and undisturbed. The first part of the subclavian gives off the vertebral, thyroid axis, and internal mammary; the second, the superior intercostal; while the third part has in most cases no branch whatever. In these anatomical differences we find the reason for the almost invariable fatality resulting on any interference with the first and second parts, and the comparative safety of ligature of the third part, without requiring to account for the difference on other grounds, such as depth of part, importance of nervous relations, or nearer proximity to the heart.

The second and third parts of both arteries are so similar to each other, that a separate account is not required for the two sides.

Ligature of Right Subclavian.—First Part.—Operation.—An incision just at upper edge of sternum and right clavicle, extending from inner edge of left sterno-mastoid transversely to outer border of right sterno-mastoid through skin, platysma, and exposing sterno-mastoid, to be joined at an angle by a second incision, which, two, three, or even four inches long, must extend along inner border of right sterno-mastoid. Flap to be raised upwards and outwards. The sternal attachment of the sterno-mastoid must then be cautiously divided, as also part or the whole of its clavicular attachment, according as room is required. The sterno-hyoid and thyroid muscles will then require similar division. The internal jugular will then be seen very prominent,¹⁶ and will require to be drawn inwards or outwards, according to circumstances. The carotid and right subclavian arteries will then be felt lying close together crossed by the pneumogastric and recurrent nerves, the latter turning behind the subclavian. The nerves must be drawn inwards; the cardiac filaments of the sympathetic will then be observed, and drawn outwards. The subclavian vein lies below, concealed by the clavicle, and will probably not be seen during the operation. The needle should be passed round the artery from below upwards, care being taken not to injure the pleura, which lies beneath and behind the artery.

Results.—Twelve cases, all of which died; ten of hæmorrhage, one of pleurisy and pericarditis, and one from pyæmia. Attempted in one case by Mr. Butcher, but the artery was too much diseased to bear a ligature. The patient died on the fourth day.

Ligature of Left Subclavian.—First Part.—This operation, which has been described by some as impossible, has, I believe, been only once performed on the living body. Operation.—Incisions as for the preceding operation, except being on the opposite side. After the skin, platysma, and muscles have been divided, as already described, the deep cervical fascia requires division close to the inner edge of the scalenus anticus. The artery lies excessively deep, and great difficulty is experienced in avoiding injury to the pleura and the thoracic duct.

Results.—Once performed by Dr. Rodgers of New York; death from hæmorrhage on fifteenth day.

Anatomical Note.—The course of the left subclavian in its first stage is much straighter, as its origin is much deeper, than on the right side. The pneumogastric, phrenic, and cardiac nerves lie parallel to its course; the œsophagus and thoracic duct lie behind it, and to its inner side.

Ligature of Subclavian.—Second Part.—This very rare operation hardly requires a separate description, as the incisions necessary for ligature of the artery in its third part will, with very slight modifications, be sufficient for the purpose.

It has, however, special elements of danger in it, involved in the unavoidable division, of part at least, or probably the whole, of the scalenus anticus. The phrenic nerve, from its position on that muscle, requires special care to avoid dividing it, and in most cases the internal jugular vein is also in the way. The branches of the thyroid axis, which cross the neck, are quite in the line of the incision. The lowest cord of the brachial plexus lies immediately behind the artery, between it and the middle scalenus. The pleura lies just below it. The subclavian vein is generally quite safe, running in front of the scalenus anticus, and at a lower level.

The presence of the superior intercostal branch adds greatly to the danger of ligature of the vessel in this position, from its interfering with a proper clot.

Results.—Dupuytren¹⁷ performed it successfully for a traumatic axillary aneurism. Auchincloss¹⁸