Commentaries on the Surgery of the War in Portugal, Spain, France, and the Netherlands / from the battle of Roliça, in 1808, to that of Waterloo, in 1815; with additions relating to those in the Crimea in 1854-55, showing the improvements made during and since that period in the great art and science of surgery on all the subjects to which they relate.

by G. J. Guthrie

LECTURE XV.

THE COMMON CAROTID ARTERY, ETC.

230. The carotid artery may be tied, in almost any part of its course, in the following manner: The patient being seated, with the shoulders supported, so that the light may fall on the neck, the head is to be bent a little forward, to relax the muscles on the fore part. An incision is then to be made on the line of the inner edge of the sterno-cleido-mastoideus muscle, by which the integuments, the platysma myoides, and the superficial cervical fascia are to be divided. The extent of this incision, in persons with long necks, may be from a line beginning parallel with the cricoid cartilage to within about half an inch of the sternal end of the clavicle: when the neck is very short, it must be begun as high up as the lower edge of the thyroid cartilage, so as to be as nearly as possible three inches in length. The sterno-cleido-mastoideus muscle is then to be drawn outward, with any vein which may be seen attached to its under edge. The pulsation of the artery under the finger will point out its situation, and the sterno-hyoideus and sterno-thyroideus muscles being drawn and kept inward, the omo-hyoideus will be seen crossing in the upper part of the hollow thus formed by the separation of these parts. The central tendinous portion of this muscle is attached and fixed by the deep cervical fascia, and lies immediately over the sheath of the vessels, particularly over the jugular vein. This fascia, which is strong although thin, is to be carefully divided below the muscle, immediately over the center of the artery, the position of which is to be accurately ascertained by the finger. At or beneath the same spot, the sheath of the artery is to be opened; and the long, thin nerve, the descendens noni, which runs upon the sheath, will at this part be seen inclining to the tracheal side of the artery. It is to be separated and drawn inward with the muscles. If the sheath of the artery be carefully opened immediately over its center, the jugular vein will scarcely interfere with it. But as it has been known to enlarge suddenly under the exertions or excitement of the patient so as to overlap the artery, it has been recommended to make gentle pressure on the vessel at the upper part of the incision, and below if necessary, in order to prevent that occurrence. The aneurismal needle is then to be introduced and passed under the artery from without inward, by which the jugular vein and the par vagum nerve will be avoided, more particularly if the sheath of the vessels has been undisturbed, save where it has been opened immediately over the artery. The point of the aneurismal needle is to be brought out close to the inside of the artery within its sheath, by which means all danger will be avoided of injuring either the recurrent or the sympathetic nerves which lie behind or to the inside of it. As to the œsophagus, thoracic duct, or thyroid artery, they are not likely to be injured by any common operator; but he should be aware that on the left side, if he be obliged to operate low down, he may meet with greater inconvenience from the jugular vein, which is more anterior to the artery, and rather overlaps it, while on the right side it inclines outward from it.

The carotid artery may be tied higher up in the following manner: The incision in this instance should be begun a little below where the former one was commenced, and should be continued upward for the same length of three inches, in a line extending toward the angle of the jaw. The head should be laid back to enable this to be done, and ought to be kept in that position by an assistant. The artery at this part of the neck is covered by the integuments, the platysma myoides muscle, and the fascia. After the muscle has been divided, the strong fascia must be carefully raised with the forceps and opened, and the operator will do wisely if he divide it upward and downward on a director. With the end of the scalpel or a blunt knife he should separate the cellular tissue from the veins, which appear in this situation, and are often the source of much embarrassment. The sheath of the artery is to be opened over the center of the vessel, and the ligature is to be passed around it as before. The descendens noni nerve runs in general on the outside of the artery in this part of the neck, and afterward crosses over to the tracheal side. The par vagum, which lies in the angle formed posteriorly by the apposition of the carotid artery and jugular vein, to which latter it is more particularly attached, is to be avoided on introducing the aneurismal needle; and on bringing it out on the inside, the same attention must be paid to prevent injury to the great sympathetic or any of its branches. The surgeon in both these operations should draw the ligature first a little outward and then inward, so as to enable him to ascertain that he has included in it nothing but the artery, which is to be tied with two knots; one end may be cut off, or both may be twisted together, and brought out of the wound opposite where the vessel has been tied. The integuments should be accurately closed by adhesive plaster, and the patient put to bed with the head bent forward, and properly supported. He should eat as little solid food as possible until after the ligatures have come away, and observe even greater precautions as to quietude than in other instances.

231. The external carotid artery may be tied by an operation conducted in a similar manner. After the first incisions have been made, and the strong cervical fascia divided, the operator must feel for the pulsating vessel, which will be found on a line parallel with the cornu of the os hyoides, below which part the common trunk usually divides into the external and internal carotids, the external being the more superficial and internal of the two at their origin. The external carotid turns with its convexity inward; nearly opposite to but rather above the os hyoides it is crossed by the ninth or lingual nerve, the digastric and stylo-hyoid muscles; it should be tied below this part.

When any of the branches of the external carotid has been wounded, it ought to be tied by a similar operation at both ends, at the part wounded. If the surgeon cannot do this, and the hemorrhage demand it, the trunk of the external carotid is the vessel on which the ligature should be placed, not that of the common carotid.

232. The internal carotid artery, when wounded near the bifurcation of the common carotid, is to be secured by two ligatures, and the steps in the operation are the same as those for exposing the external carotid, the surgeon recollecting that the internal carotid is more deeply seated and to the outside of the external. A ligature may be placed on the internal or external carotid, close to the bifurcation, with safety; but if the wound of either vessel should encroach on the bifurcation, one ligature should be applied on the common trunk and another above the part wounded; but as neither of these would control the collateral circulation through the uninjured vessel, whichever of the two it might be, a third ligature should be placed on it above the bifurcation.

When the internal carotid is wounded through the mouth, at the upper part of the neck, it should be secured by the operation described on page 248, Aph. 216.

233. The arteria innominata arises from the upper part of the arch of the aorta, generally on a line nearly parallel with the upper edge of the cartilage of the second rib, ascends obliquely toward the right side, and usually divides opposite the sterno-clavicular articulation into the right subclavian and the right carotid arteries; the last of which appears to be its continuation, although the smaller in size. The arteria innominata is about two inches in length, rarely exceeding two inches and a half, although it is very variable both in length and situation, so much so as sometimes to render the operation of placing a ligature upon it during life impracticable. It is covered by the right vena innominata, which receives the left at a right angle, near the origin of the artery. Exterior to the vena innominata are the sterno-thyroideus and sterno-hyoideus muscles, some strong fascia covering the vein at its upper part, and the first bone of the sternum. The arteria innominata may ascend higher in the neck before it divides, in which case its pulsation will be perceptible in front of the trachea, and the subclavian artery will cross higher in the neck, which is one reason for not continuing the external incision down to the sterno-clavicular articulation in the operation on the right carotid. The subclavian artery, given off behind or a little above the articulation, proceeds outwardly for the space of one inch before it reaches the inner edge of the scalenus anticus muscle, which is about half an inch in width; so that the subclavian artery, when it clears the outer edge of the scalenus anticus muscle in a tall man, is not more than one inch and a half or three-quarters from its origin, even to the spot at which a ligature is usually placed upon it. The first branch given off is the vertebral on the upper and back part of the artery, distant half an inch from the carotid at the bifurcation. The thyroid axis is given off at the anterior and upper part of the artery, a quarter of an inch more outwardly, and the internal mammary often arises directly opposite from the anterior and inferior part of the artery, descending into the chest behind the junction of the first and second ribs with their cartilages. The inner edge of the scalenus anticus muscle is close to these two last vessels. The phrenic nerve, crossing this muscle obliquely, lies on the outside of the thyroid axis, and on the inside of the internal mammary artery; having crossed the subclavian artery at this part, it descends between it and the junction of the internal jugular and subclavian veins to the chest. Internal to this, some small branches of the great sympathetic nerve, which lies behind, pass over the artery; and still more internal, but distant about a quarter of an inch from the carotid artery, the par vagum crosses likewise. The only point at which the subclavian artery can be tied internal to the edge of the scalenus anticus muscle is at this point, on the inside of the par vagum, in a space scarcely more than one-quarter of an inch in width, to which the carotid will be the best guide. It would appear that a ligature may be as readily applied around the innominata, immediately below the bifurcation, as around the subclavian, although little or no reliance can be placed on success attending either operation.

From this view of the parts it will be evident that the operation may be done in the following manner: Raise the shoulders of the patient, and allow the head to fall backward, by which the artery will be drawn a little from within the chest. Let an incision be made over and down to the sterno-cleido-mastoideus muscle, the sternal origin of which, and nearly the whole of the clavicular origin, should be divided on a director, carefully introduced below it, avoiding some small veins which run below and parallel with its origin. An incision is now or previously to be made, two inches in length, through the integuments, along the inner edge of the muscle, which will admit of its being raised and turned upward and outward. Some cellular texture being torn through, the sterno-hyoideus muscle is brought into view, and should be divided on a director. The sterno-thyroideus is then to be cut through in a similar manner. A strong fascia and some cellular texture here cover the artery, having the nerves above mentioned running beneath it, the carotid being to the inside, the internal jugular vein to the outside. By following the carotid downward, the finger will rest on the innominata and on the origin of the subclavian, and a ligature may be placed on either. If on the innominata, the aneurismal needle (and several kinds should be at hand) should be passed from without inward, immediately below the bifurcation, close to the vessel. If on the subclavian, the surgeon must recollect that there is only about a quarter of an inch of this artery on which the ligature can be applied; this small space being bounded internally by the carotid artery, and externally by the par vagum above, and the vertebral artery below. The ligature should be applied close to the vertebral artery, the needle being passed from below upward, the greatest care being taken to avoid the recurrent nerve, which separates from the par vagum at this part, and winds under the subclavian and carotid arteries, to be continued upward to the larynx. If the ligature be placed on the arteria innominata, the same care must be taken to draw the par vagum outward, and to avoid the recurrent nerve. The edges of the wound should be brought together and dressed in the usual manner, the head being bent forward on the trunk, and maintained in that position, in order to relax the parts, and admit of their being kept in apposition.

This operation ought only to be performed in cases of aneurism of the subclavian artery, in which it is presumed that the disease extends as far as the external edge of the scalenus anticus muscle, but not more inwardly. The arteria innominata has certainly been tied five, if not six times in vain, and in two or three other instances the attempt failed, the operator not succeeding in his object. In Dr. Mott’s case the ligature came away on the fourteenth day, but the patient died from hemorrhage, in consequence of ulceration of the artery, on the twenty-sixth day after the operation. Dr. Graëfe’s patient also died from hemorrhage on the sixty-seventh day. It is evident, from these cases, that a man may live so long after the operation as to show that he does not die from its immediate effects, or from any that must necessarily take place. It is therefore possible that if the operation be often repeated it may eventually be successful.

234. The left subclavian artery rises perpendicularly out of the chest like the innominata, but on a plane much posterior to it, so that at the part where the vertebral artery is given off, which is about an inch and a half from the origin of the artery, it lies nearly an inch deeper from the surface than the vessel on the opposite side. It is covered by, or is more directly connected with, the important parts which are also in the vicinity of the right subclavian. The pleura adheres to it, and can scarcely avoid being torn in putting a ligature around it. The par vagum is parallel with and anterior to it. The internal jugular vein and the left vena innominata lie over it. The thoracic duct and œsophagus are connected with it; and the carotid artery is in front. So that with the most careful dissection it is not a very easy matter to place a ligature upon the ascending portion of the left subclavian artery, without doing more mischief than is compatible with the life of the patient.

Aneurisms of the arch of the aorta have been sometimes known to appear so far beyond the outer edge of the scalenus anticus muscle as to impress the surgeon with the idea that they arose from the subclavian artery, and that an operation on that vessel might be attended with success. This error is not likely, however, to occur in the present day, for the stethoscope will always point out the existence of such an aneurism within the chest, and will therefore demonstrate the impropriety of the operation. Aneurisms of this nature are usually attended by some circumstances indicating their more internal origin, independently of the information derived from the stethoscope. An operation should only be attempted when the case is free from doubt.

Whenever an aneurismal tumor in the neck is accompanied by any alteration of the sterno-clavicular articulation, the case is clearly one totally unfitted for any operation. The same may be said of any case of aneurismal swelling, either internal or external to it, in which the stethoscope applied on the sternum in the course of the arteria innominata, or of the arch of the aorta, indicates disease. A swelling at the root of the carotid is more likely to be an aneurism of the arch of the aorta, or of the arteria innominata, than of the carotid itself. The stethoscope will remove all doubt.

235. The subclavian artery has been frequently tied above the clavicle, external to the scalenus anticus muscle. It should be done in the following manner: The patient being placed horizontally on the table, in such a situation that the light may be directed into the hollow in the bottom of which the artery is to be tied, the shoulder is to be depressed, and an incision made along the edge of the clavicle, commencing one inch nearer the sternum than the clavicular edge of the sterno-cleido-mastoideus muscle, and carried outward to the extent of three inches and a half or four inches. The platysma myoides and the superficial fascia are to be divided, taking care not to injure the external jugular vein, which should be drawn to the outer side of the wound. By this incision the edges of the trapezius and sterno-cleido-mastoideus muscles will be exposed.

The object of the operation is in the first instance to reach the outer edge of the anterior scalenus muscle: this lies immediately below the outer edge of the clavicular portion of the sterno-cleido-mastoideus, and the division of a portion of this part of the muscle will greatly facilitate the subsequent steps of the operation, although it may be done without it. The artery will be found crossing over the first rib at the very edge of the attachment of the scalenus anticus to it; but a quantity of cellular substance and fascia intervenes, which must be torn through before it can be exposed. This should be done with a blunt, round-pointed knife, in a line parallel with the first incision, but more immediately over the outer edge of the scalenus muscle. The omo-hyoideus muscle passing obliquely across the root of the neck will be in this manner exposed, which should be clearly done, because it narrows the space in which the operation is to be performed to a small triangle; the outside and apex of which is formed by this muscle, the inside by the scalenus anticus, the base by the rib, above it the subclavian vein, and above it again, but under the clavicle, the supra-scapular artery and vein. The blunt knife, working in the triangular space, will first expose one or more of the nerves of the axillary plexus, which again diminishes the space; more inwardly the scalenus anticus will be felt, and should be seen by tearing through the thin fascia which lies behind the omo-hyoideus, and is connected with it. The point of the finger, assisted if necessary by the blunt knife, should be passed along the edge of the muscle until it rests on the first rib, and at the angle formed between the muscle and the rib the artery will be found and known by its pulsation. The operator should detach the artery in a slight degree from its connections, with the nail of the forefinger, and the aneurismal needle should be passed in preference from below upward, by which the pleura will be avoided. After the ligature has been passed under the artery, the vessel should be pressed upon with the finger, while the ligature is firmly held in the other hand, by which the circulation through the artery will be stopped. The pulsation in the tumor and at the wrist should cease, when the ligature may be tied with a double knot; for doing this, one or two steel probes, having a ring at the end, placed at a right angle with the shaft, will afford great assistance.

In some instances, particularly in short-necked persons, the omo-hyoideus lies close to the clavicle, and requires to be drawn upward and outward from it. In others, the lowest nerve of the axillary plexus lies over the artery, and may be mistaken for it. When the veins coming from the neck are large and numerous, great care should be taken to avoid injuring them, as they frequently cause not only much hemorrhage, but great delay. Great care must also be taken in all these operations to prevent the ingress of air into any of the veins which may by accident be opened, as its admission in quantity has occasioned sudden death, although the entrance of a few bubbles may not be so dangerous as has been supposed.

236. When the axillary artery is to be tied for a wound caused by a sharp-pointed or other instrument which has been forced through the pectoral muscle or under it from the axilla, the patient is to be firmly supported or placed in the horizontal position, the arm to be slightly separated from the body, and an incision made in the course of the axillary artery, through the integuments, superficial fascia, and the great pectoral muscle—in fact, through the anterior fold of the armpit. The length of the incision will depend on the part at which the artery is to be secured. The parts divided being separated, the pectoralis minor will be seen crossing to the coracoid process at the upper part of the wound, and the artery may be felt below it, inclosed in its cellular sheath, with the nerves of the arm and its venæ comites. All other modes of attempting this operation are unworthy consideration, and ought to be discarded as dangerous and insufficient.

At the lower edge of the pectoralis minor, the artery is crossed by the outer of the venæ comites, which passes between the external cutaneous and the external origin of the median nerve, at the spot where they separate from the plexus. The artery may be tied below this separation, or the nerves and vein may be drawn to the outside, and the artery tied above the union of the external with the internal root of the median nerve as high as the origin of the arteria thoracica acromialis, the pectoralis minor being either raised and pushed upward, or divided if necessary. The internal root of the median nerve is in connection with the internal cutaneous and ulnar nerves; the larger of the venæ comites is to the inside and behind, but as it ascends it receives its fellow, and with the cephalic vein forms in front of the artery the subclavian vein.

237. The brachial artery can be traced by its pulsation from the lower edge of the teres major muscle to below the bend of the arm, where it is covered by the pronator radii teres muscle. At first it is on the ulnar side of the humerus, resting on the triceps, and slightly overlapped by the coraco-brachialis and biceps muscles. In the middle of the arm it rests on the tendon of the coraco-brachialis, is close to the bone, and lies under the lower edge of the biceps; in which situation it may always be compressed by bending the forearm, so as to cause the belly of the biceps to enlarge, when pressure made immediately below it will arrest the circulation in the brachial artery. It then crosses toward the anterior part of the arm, and rests on the brachialis anticus muscle until it passes the bend of the elbow. It is accompanied by two veins, which are connected with it by a loose cellular membrane forming a sheath. The external cutaneous and median nerves lie a little to the outside of the artery in the upper third of the arm. In the middle third the median nerve lies generally in front of, but sometimes between the artery and the bone, and is on the inside at the inferior part. The internal cutaneous nerve runs parallel with but superficial to the artery, the ulnar nerve nearer but posterior to it. When a ligature is to be placed on the brachial artery in the upper part of its course, the incision should be made about three inches in length, directly on the line of the pulsating vessel, by which all mistakes will be avoided. The integuments should be divided carefully, that the internal cutaneous nerve may not be injured; the fascia is then to be cut through and the forearm bent, when the vessels and nerves will be relaxed. The artery is to be separated from its veins, one on each side; and it must be recollected that the external cutaneous and median nerves are to the radial side of the artery, the internal cutaneous and the ulnar nerves to the ulnar side of it. In the middle of the arm the median nerve lies immediately over the artery, except in those cases where it passes behind it; when it lies in front it may be mistaken for the artery, from the pulsation being communicated to it. The incision should be to the same extent of three inches, directly in the course of the artery, and the ligature should be passed from the ulnar to the radial side of the vessel, in order to avoid the possibility of including either the internal cutaneous or the ulnar nerve, and for the purpose of excluding both the veins.

238. The brachial artery, a little below the bend of the arm, divides into the radial and ulnar arteries—the radial being the continuation of the brachial in direction, the ulnar in size. The brachial artery, at the bend of the arm, is cushioned on the brachialis internus muscle, having the tendon of the biceps on the outside, the median nerve on its inside, which is at first continued on the same side of the artery, which now takes the name of ulnar. This vessel inclines toward the ulna for about an inch, and then passes between the two origins of the pronator radii teres muscle; the median nerve crosses it at this part to get into the middle of the arm, and is then separated from it by the ulnar origin of the muscle. The artery continues its course, inclining outwardly, under the pronator radii teres, the flexor carpi radialis, the palmaris longus, and the flexor sublimis muscles, lying on the flexor profundus. On clearing the ulnar edge of the flexor sublimis, it is covered by the flexor carpi ulnaris, the course of the artery having been obliquely under these muscles to the extent of two inches. To tie it in any part of this course, they must be more or less divided, and the only difficulty or danger arises from the median nerve, which lies deeper under the radial origin of the pronator teres. But the whole of the muscular fibers may be divided, without injuring the nerve, by successive and careful incisions through them until the artery and nerve are exposed, and a ligature may then be applied above and below the wound in the vessel. It may be supposed, by way of elucidation, that a man has received a wound from a sword through the flexor muscles, which injures also the ulnar artery, as may be presumed from its situation and the continued and impetuous flow of blood. It may be further supposed that this wound is in a slanting direction from the ulna toward the radius. The surgeon, if he thinks he can calculate the point at which the artery is injured, should cut down upon it in the direction of the fibers of the intervening muscles, and even through them until he reaches the artery; but if he has erred in his calculation, he should introduce a probe into the wound, and, after having ascertained the line it has taken, he should cut, if necessary, across the muscular fibers in that direction until he exposes the bleeding artery; if he be careful not to divide the median nerve, no inconvenience will arise from the operation. (Aph. 184, page 192.)

239. If the ulnar artery be wounded near its origin, through the radial side of the pronator teres muscle, an incision should be made through the integuments and the aponeurosis of the biceps muscle; the pronator muscle being then exposed, it is to be drawn inward and downward, or toward the ulna, and the dissection continued until the median nerve is brought into view. The probe introduced through the original wound will lead to the artery, the pulsation of which will be felt and the bleeding seen. Where the nerve crosses the artery, the vessel will be found above or to the radial side of it, and to the ulnar side below. It may be tied above without dividing a muscular fiber; but at the part where the nerve crosses, and below it, some fibers of the pronator teres must be divided, and in some cases the whole of them, before the artery can be properly secured by two ligatures; but this division is of little or no consequence, as the muscular fibers reunite without difficulty.

240. To tie the ulnar artery in the middle third of the arm, the surgeon should bend the wrist, and trace upward the tendon of the flexor carpi ulnaris as far as it can be felt. At the point where it becomes indistinct, an incision should be commenced and carried upward for the space of four inches; the fascia is then to be divided to the same extent, when the flexor carpi ulnaris may readily be traced upward by its tendon, which is on the radial side of it; this muscle may then be easily separated from the flexor sublimis, beneath the edge of which the artery will be found covered by the deep-seated fascia, having a vein on each side, and the ulnar nerve to the ulnar side of it. By this method of proceeding the artery will be readily exposed, which is not always the case by any other manner of operating, and it may be tied as high up as where it passes from under the flexors of the arm.

The ulnar artery may be easily tied near the wrist, where it is most superficial. Bend the wrist, and make the flexor carpi ulnaris act, when the tendon will be felt internal to the styloid process of the ulna; make an incision two inches and a half in extent along the radial edge of this tendon, dividing the fascia of the arm which covers it. The artery will be felt below the deep-seated fascia, and, on dividing it, will be seen with its venæ comites, the ulnar nerve being behind it; that nerve must be avoided, in the application of a ligature.

241. The radial artery may be secured by ligature with great ease in any part of its course to the wrist. At the upper third of the arm, the radial artery is covered by the approximation of the supinator radii longus and pronator radii teres muscles. To expose it at this part, a line may be drawn from the middle of the bend of the arm to the thumb, which will indicate its course; or the supinator radii longus being put into action, an incision is to be made from the bend of the arm obliquely outward along its ulnar edge to the extent of three inches, avoiding the median vein, but dividing the integuments and the fascia. The supinator muscle is then to be gently separated from the pronator radii teres by the handle of the knife, and the artery will be felt covered by the deep-seated fascia; on the division of which, it will be seen with its venæ comites lying on some adipose membrane, and on some branches of the musculo-spiral nerve, which separate it from the tendon of the biceps, and are to be carefully avoided. The musculo-spiral nerve itself lies nearer the radius, rendering it advisable to pass the aneurismal needle from that side.

In the middle third of the forearm, the inner edge of the supinator radii longus marks the line of the incision, which should be to the extent of three inches. The fascia being divided, the supinator longus is to be separated from the flexor carpi radialis, and, on the division of the deep fascia, the artery will be found passing with its venæ comites over the insertion of the pronator radii teres and the radial origin of the flexor digitorum sublimis. The musculo-spiral nerve lies close to the radial side of the artery.

Near the wrist, the radial artery may be tied with great facility. Make an incision two inches and a half long on the radial side of the tendon of the flexor carpi radialis, which becomes prominent on bending the wrist; the superficial and deep fasciæ are to be divided, when the artery and its veins will be exposed; the nerve has not accompanied the artery to this point, where it lies on the pronator quadratus, whence it turns below the styloid process of the radius to the back of the hand.

The radial artery, on giving off the superficialis volæ to the palm of the hand, near the end of the radius, inclines outward, and, when between its styloid process and the trapezium, lies beneath the two first extensors of the thumb. Passing onward to reach the angle formed by the metacarpal bones of the thumb and forefinger, it lies first in a triangular space between these two extensor muscles and the third, in which situation a ligature may readily be placed upon it by a simple incision. Proceeding onward, the artery passes under the third extensor and lies to the outside of it, where it may also be secured by ligature without difficulty, just before it dips into the palm and gives off the principal artery to the thumb. After the radial artery has reached the inside of the hand, to form the deep-seated palmar arch, it crosses the metacarpal bones nearly at a right angle, covered by all the muscles, tendons, and nerves of the palm. A branch of the ulnar nerve is here seen going to the muscles of the thumb. If the graduated compression recommended in Aphorism 208, page 238, together with due pressure on the radial and ulnar arteries at the wrist, should fail to arrest the bleeding from a wound at this part, the two muscles, forming what may be and is called the web, between the thumb and forefinger should be divided until the wounded artery can be seen. These muscles are the adductor pollicis on the inside, and the adductor indicis on the back of the hand; and their division would lead to little or no inconvenience. If a man, in opening an oyster, were to divide these muscles by an accidental thrust of his knife, it would not be considered a serious accident, although some surgeons might be dismayed if desired to divide them surgically, to expose the artery at the spot where it has been wounded.