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 did it for a large true aneurism, but the patient died sixty-eight and a half hours after the operation. Liston cut through the outer portion of the scalenus with success for an idiopathic aneurism. Thirteen have been collected by Wyeth with four recoveries and nine deaths.
Ligature of Subclavian.—Third Part.—For this comparatively common operation, various methods of procedure have been suggested and employed.
In the dead body, where the axilla is free from swelling, and in thin patients, the artery in this third stage is tolerably superficial, and can be secured with ease. But in very muscular men, with short necks and well curved clavicles, and specially when the axilla is filled up with an aneurism, and the shoulder cannot be depressed, the operation becomes very difficult.
Operation of Ramsden, Liston, and Syme.—Position.—The patient lying on his back with his shoulders supported by pillows, and his head lying back, and drawn to the opposite side; the shoulder of the affected side must be depressed as much as possible.
Incisions.—(Plate I. fig. 8.)—One through skin, superficial fascia, and platysma, along the upper edge of the clavicle, for at least three inches from the anterior edge of the trapezius to the posterior border of the sterno-mastoid, and in muscular subjects freely overlapping the edges of both muscles. Another two inches in length along posterior border of sterno-mastoid meets the first at an angle. On reflecting the chief flap thus made upwards and backwards, the external jugular will be seen, and, if possible, must be drawn to a side; if not, it must be divided, and both ends tied. The lower edge of the posterior belly of the omohyoid must then be sought; this leads at once to the posterior or outer margin of the scalenus anticus. The connection of the deep fascia to that muscle must then be very carefully scraped through, and by tracing the muscle to its insertion to the first rib, the artery is at once reached, lying behind the insertion. The pulsation of the vessel between the forefinger and the first rib will prove a great assistance; yet care is required, lest one of the branches of the brachial plexus be secured instead of the artery. The lowest cord lies very close to the vessel. The subclavian vein is not likely to give much trouble, from its being on a lower level, and (unless very much dilated) nearly concealed by the clavicle. The suprascapular artery is also hidden, but the transverse cervical crosses the very line of incision, and may give trouble, being occasionally much enlarged, so much so as even for a time to have been mistaken for the subclavian itself. If possible, both these branches should be saved, as being important means of carrying on the anastomosis for the future support of the limb.
An absorbent gland is occasionally in the way, and has even been mistaken for the vessel and carefully cleaned. Such may be removed without scruple.
Care must be taken not to injure the pleura, which lies immediately behind and below the vessel at the seat of ligature. Various instrumental devices have been invented for passing the ligature. The simplest seems still to be best, a common aneurism-needle with a considerable curve.
Other methods of operating.—A single curved incision above the clavicle, with its concavity upwards, of about three or four inches long, with its inner end rather higher than the outer (Green, Fergusson).
A linear transverse incision in the same situation (Velpeau).
A single linear incision perpendicular to the clavicle (Roux).
An arched incision (Plate IV. fig. 2) with its convexity outwards, and its base on the posterior edge of the sterno-mastoid, from three inches above the clavicle to the clavicular attachment of the muscle (Skey).
Results.—Dr. Wyeth's Tables in 1877 give 251 cases with 134 or 53 per cent. of deaths.
The late Mr. Furner of Brighton reported a most interesting case, in which he tied both subclavian arteries at an interval of two years in the same patient, for axillary aneurisms, with success.
Ligature of Axillary.—Anatomical Note.—This vessel, the next stage in the continuation of the subclavian downwards, may be defined surgically as extending from the clavicle to the lower border of the teres major. From the depth of the vessel at its upper part, the numerous nerves, and the close proximity of the vein, the surgeon has carefully to study the anatomical relations. It, like the subclavian, is commonly divided into three stages, and, also like the subclavian, these stages are defined by the relations of the artery to a muscle, the pectoralis minor. Surgically we may draw a very close parallel between the two vessels, for we find that in the axillary, as in the subclavian, the first stage is very deep, and very rarely amenable to ligature; the second, still deeper and more rarely attempted, as in both the operation involves division of a deep muscle; while the third stage in each is the one most frequently chosen by the surgeon.
First Stage.—Between the lower edge of the first rib and upper border of the pectoralis minor the vessel is deeply seated, contained in that process of deep fascia called the costo-coracoid membrane, and covered above by skin, platysma, and the clavicular portion of the pectoralis major. It lies on the first intercostal muscle and the upper digitation of the serratus magnus, while the cords of the brachial plexus are on its acromial side, and the axillary vein in close contact with it on its thoracic side, and frequently overlapping the artery.
Operation.—The great desideratum is free access. An incision (Plate I. fig. 9), semilunar in shape, with its convexity downwards, must extend from half an inch outside of the sterno-clavicular articulation to very near the coracoid process, stopping just before it arrives at the edge of the deltoid, in order to avoid injury of the cephalic vein. It must include skin, fascia, and platysma, and the flap must be thrown upwards. The clavicular portion of the pectoralis major must then be divided right across its fibres, which will retract. The arm must then be brought close to the side to relax the pectoralis minor, which must be drawn aside. The artery will then be felt pulsating, but hidden by the costo-coracoid membrane, which acts as its sheath. This must be carefully scratched through, the nerves pulled outwards, the vein avoided and pulled downwards and inwards, and the thread passed round from within outwards. (Manec, Hodgson, and, with slight modification in the incision through the skin, Chamberlaine.)
Ligature has been performed in this position by separating the pectoralis and deltoid muscles, without dividing the muscular fibres (Roux, Desault).
To attempt to gain access between the clavicular and sternal portions of pectoralis major, as has been proposed by some, is almost impracticable in the living body, from the position of the vein, to which, rather than to the artery, this incision leads.
Ligature of Axillary, in its second stage, is not an advisable operation, when it is merely intended to throw a ligature round the artery for an aneurism lower down.
It has been performed at least twice by Delpech, but it is a rude procedure; in his cases, after the muscle was cut, a dive with the finger was made to collect the whole mass of vessels and nerves, and bring them to the surface near the collar-bone; in this position it is said the artery was easily isolated and tied.
In Mr. Syme's operation of cutting into large axillary aneurisms, and tying both ends of the vessel, the pectoralis minor may, indeed generally has, to be divided, and must take its chance without any special notice or precaution, in the sweeping, free incisions required.
Ligature of Axillary in its third stage.—This is an operation very much more common, more easy of accomplishment, and safer in its results than either of the preceding; the artery in this stage being more superficial, in fact almost subcutaneous.
Operation.—The arm being extended and supinated, an incision (Plate I. fig. 10) two and a half or three inches long, must be made in the base of the axilla over the artery, involving at first skin and superficial fascia only; the deep fascia is then exposed and must be carefully scraped through, avoiding injury of the basilic vein, if (as sometimes occurs) it has not yet dipped through the fascia. The vessel can now be felt; the median nerve which lies over the artery, or slightly to its outer side, must be drawn outwards, and the axillary vein, which lies at the thoracic side, but often overlaps the vessel, must be carefully drawn inwards. The ligature must then be passed from within outwards.
When the patient is very fat or muscular, the coraco-brachialis muscle may be required as a guide to the vessel; but in general its superficial position renders any guide quite unnecessary, even in the dead body.
Anatomical Note.—While in each stage the axillary artery gives off branches, those arising from the third stage are by far the most important, especially the subscapular, which leaves it at the edge of the muscle of the same name. To avoid these the ligature should be applied as low down on the vessel as possible, and, in point of fact, the operation called ligature of the third stage of the axillary is, anatomically speaking, really ligature of the brachial high up, and where there is room at all, there will be the less chance of secondary hæmorrhage, the greater the distance is between the ligature and the great subscapular branch.
Mr. Syme's Operation for Axillary Aneurism.—Description of the operation in his own words:—
"Chloroform being administered, I made an incision along the outer edge of the sterno-mastoid muscle, through the platysma myoides and fascia of the neck, so as to allow a finger to be pushed down to the situation where the subclavian artery issues from under the scalenus anticus and lies upon the first rib. I then opened the tumour, when a tremendous gush of blood showed that the artery was not effectually compressed; but while I plugged the aperture with my hand, Mr. Lister, who assisted me, by a slight movement of his finger, which had been thrust deeply under the upper edge of the tumour, and through the clots contained in it, at length succeeded in getting command of the vessel. I then laid the cavity freely open, and with both hands scooped out nearly seven pounds of coagulated blood, as was ascertained by measurement. The axillary artery appeared to have been torn across, and as the lower orifice still bled freely, I tied it in the first instance. I next cut through the lessor pectoral muscle close up to the clavicle, and holding the upper end of the vessel between my finger and thumb, passed an aneurism-needle, so as to apply a ligature about half an inch above the orifice."19
In a similar operation lately performed by the author for traumatic aneurism, the result of a stab, very little blood was lost, though no incision was made above the clavicle. The patient made a good recovery.20
Ligature of Brachial.—To arrest hæmorrhage from a wound of the artery itself, no special directions are required, except to enlarge the wound, and secure the vessel above and below the bleeding point. There are, however, rare cases in which for bleeding in the palm (after all other means have failed), or for aneurism lower down the arm, a ligature may be necessary.
Operation.—The biceps muscle, at its inner edge, is the best guide to the position of the incision, or if it be obscured by fat or œdema, a line extending from the axilla, just over the head of the humerus to the middle of the bend of the elbow will define its course. An incision (Plate I., fig. 11) three inches in length, about the middle of the arm (when you have the choice of position), through skin and superficial fascia, will expose the deep fascia, and probably the basilic vein. Drawing the latter aside, cautiously divide the deep fascia. The artery is then exposed, but in close relation to various nerves; of these the ones most likely to come in the way are—1. The median, which lies in front of, but a little to the outside of the artery, though in some rare cases it lies behind it; 2. The internal cutaneous; 3. The ulnar, both of which ought to be rather to the inside of the artery. Two brachial veins accompany and wind round the vessel, occasionally interlacing. Pulsation will, in the living body, usually suffice to distinguish the artery from the other textures, and the ligature may be passed from whichever side is most convenient.
Note.—The relation of the median nerve to the vessel varies according to the part of the arm—thus, as low as the insertion of the coraco-brachialis it is to the outer side, as has been described, it then crosses the vessel obliquely, and two inches above the elbow it is on the inner side of the artery. Again, the operator must never forget the possibility of there being a high division of the artery. This occurs, Mr. Quain has shown, perhaps once in every ten or eleven cases, and may necessitate ligature of both trunks.
In those cases (once much more frequent than at present) where an aneurism has formed after a wound of the brachial at the bend of the arm in venesection, the aneurism may be either circumscribed or diffuse.
If circumscribed, it is advised by some surgeons, specially by the late Professor Colles of Dublin, that the brachial should be tied immediately above the tumour. In most cases of circumscribed, and in all such cases of diffuse aneurism, the preferable operation is boldly to lay open the tumour, turn out all the clots, seek for the wound in the artery, and tie the vessel above and below. A tourniquet above, or, better still, a trustworthy assistant, prevents all fear of hæmorrhage, and such a radical operation exposes the limb to far less chance of gangrene than do any attempts at removing or lessening the tumour by pressure (as recommended by Cusack, Tyrrell, Harrison), and is much more certain than a mere ligature above.21
Ligature of Vessels in Fore-arm.—Here, as also we found is the case in the leg, it is almost useless to go on giving exact directions as to the method of throwing a ligature round the vessels in all possible situations.
For below the elbow spontaneous aneurism is almost unknown, and even traumatic aneurisms are extremely rare. It is therefore for hæmorrhage only that the vessels are likely to require ligature, and it is a rule in surgery that to enlarge the wound and to apply a ligature above and below the bleeding point is better practice than to apply a ligature at a distance.
In the case of wounds of the palmar arch, it is extremely difficult, and very apt to injure the future usefulness of the hand, thus to seek for the bleeding point under the palmar fascia, and for these, ligatures of radial and ulnar have occasionally been practised. However, as even this has proved ineffectual, and the interosseous has proved sufficient to continue the bleeding, ligature of the brachial at once is preferable to ligature of so many branches in the fore-arm.
The use of graduated compresses, carefully applied, combined with flexion of the elbow over a bandage, will generally prove sufficient to check such hæmorrhage from the palm, without having recourse to either of the above more severe measures.
Note.—As in the lower limb at page 24, and for the same reasons, I here insert a brief account of the methods of tying the ulnar and radial arteries.
1. Ligature of Ulnar.—Only admissible in the lower half of its course. Operation.—Use the tendon of the flexor carpi ulnaris as a guide, and make an incision along its radial edge, at least two inches in length; expose the deep fascia of the arm and then cautiously divide it; then bending the hand, the flexor carpi ulnaris is relaxed, and the artery is found lying pretty deeply between it and the flexor sublimis digitorum. The ulnar nerve lies at its ulnar side, and the venæ comites accompany the artery. In a tolerably muscular arm, the incision will have to be about an inch inside of the ulnar border of the limb.
2. Radial.—This artery lies more superficial than the preceding, and may be tied at any part of its course.
A. Operation in upper part of fore-arm. Here the artery lies in the interval between the supinator longus and the pronator radii teres. In a muscular arm, the edge of the former muscle is the best guide; in a fat one, the incision may be made in a line extending from the centre of the bend of the arm to the inner edge of the styloid process of the radius. The deep fascia must be exposed and opened, and the muscles relaxed and held aside. The radial nerve lies on the radial side of the vessel.
B. Operation in lower half of arm. Here the vessel is more superficial, lying in the groove between the flexor carpi radialis and supinator longus. An incision two inches in length, and parallel with these tendons, easily exposes the artery. The nerve is still on its radial side.
C. Operation at first metacarpal. The artery may be tied easily enough in the triangular space bounded by the extensors of the thumb, on the dorsum of the proximal end of the first metacarpal bone. Skey22 recommends a transverse,—Stephen Smith23 and others, a longitudinal incision. The author had lately to secure the radial in its lower third, the superficialis volæ, and the radial again in the triangular space, in a case where division of the artery by a transverse cut had caused a large aneurism to form close above the annular ligament.
Table illustrating anastomotic circulation after ligature of arteries of neck and upper limb.
1. Common carotid.
(a) Across middle line: thyroids, linguals, facials, occipitals; also terminal branches of external carotids; also internal carotids by circle of Willis.
(b) Of same side: occipital with vertebral; superior thyroid with inferior thyroid, etc.
2. Subclavian, 3d part.
Suprascapular with dorsal branches of subscapular; posterior scapular with costal and muscular branches of subscapular. Thoracic anastomosis between internal mammary and intercostals, with branches of axillary.
3. Axillary and brachial. Anastomosis varies with the position of the ligature, but is very free between the various muscular branches of these vessels.