Part 29

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.

LECTURE XVI.

INJURIES OF THE BRAIN.

242. Injuries of the head affecting the brain are difficult of distinction, doubtful in their character, treacherous in their course, and for the most part fatal in their results. The symptoms which appear especially to indicate one kind of accident are frequently met with in another. It may even be said that there is no one symptom which is presumed to demonstrate a particular lesion of the brain, which has not been shown to have taken place in another of a different kind. Examination after death has often proved the presence of a most serious injury the existence of which had not even been suspected; and death has often ensued immediately, or shortly after the most marked and alarming symptoms, without any adequate cause for the event being discovered on dissection. One man shall lose a considerable portion of his brain without its being productive at the moment of the slightest apparent functional inconvenience; while another shall fall, and shortly die without an effort at recovery, in spite of any treatment which may be bestowed upon him, after a very much slighter injury inflicted apparently on the same part. During the war with the United States, in 1814, a soldier in Canada was struck by a ball which lodged in the posterior part of the side of the head; the wound healed, and the man returned to his duty. Twelve months afterward, having got drunk, he fell in the streets of Montreal, and died. The ball was found lying on the corpus callosum, where it had made a small hole or sac for itself. After the battle of Waterloo, I recommended, in the case of a soldier similarly wounded, that nothing should be done unless symptoms arose demanding the use of the trephine; as none occurred, and the wound healed, the man was sent home to Colchester, where he got drunk, and fell dead in the marketplace. The ball was lodged deeply in a cyst in the posterior lobe of the brain. Persons rarely live with a foreign body lodged in the anterior lobe of the brain, although many recover with the loss of a portion of the brain at that part. An injury of apparently equal extent is more dangerous on the forehead than on the side or middle of the head, and much less so on the back part than on the side. A fracture of the vertex is of infinitely less importance than one at the base of the cranium, which, although not necessarily fatal, is always attended with the utmost danger. The treatment of these several injuries (although they may be at first sight apparently similar) cannot, and must not be alike in all--a fact which should always be borne in mind in their management. In civil life, both in hospitals and among private persons, injuries of the base of the cranium are most frequently met with, because they are generally the consequence of falls; while in military life injuries of the base of the skull are rare, and those of other parts are common. The practice of the military surgeon, with respect to injuries of the cranium and its contents, is therefore more successful, all things considered, than that of the surgeon in civil life, and particularly in a great metropolis; this may perhaps account for some of the discrepancies in opinion which have existed between them.

243. Many physiologists have thought they could indicate the part of the brain injured from the symptoms which followed, and there are some which do not admit of dispute as to their cause; but there are very many which at present do not admit of being distinctly traced to their source. Birds, small quadrupeds, fishes, and reptiles will live for some weeks after nearly all the contents of the skull have been removed. Sensation, volition, memory, judgment, sight, hearing, and all other sensations are lost by the removal of the cerebral hemispheres. The mobility of the iris is destroyed, not by the removal of the hemispheres, but of the corpora quadrigemina. If the cerebellum be cut away, a bird can no longer jump, walk, or retain its natural position, but it can move and live. When the medulla oblongata, or medulla spinalis, or the nerves of these parts, have been divided, muscular contraction ceases, and all power of movement is lost. Life is destroyed because respiration ceases when the medulla oblongata is divided at or immediately below the origin of the eighth pair of nerves. The removal of any one of these nervous parts in the lower animals only weakens the powers of those which remain. In man it destroys them, and life is extinguished.

244. Respiration consists of four movements--1, the opening of the mouth and dilatation of the nostrils; 2, the opening of the glottis; 3, the elevation of the ribs; 4, the contraction of the diaphragm. The division of the dorsal spinal marrow, below the origin of the phrenic nerve, paralyzes the movement of the ribs; above the phrenic nerves it paralyzes the diaphragm, and respiration ceases; the yawning or opening of the mouth and glottis alone remain. On dividing the point of origin of the par vagum, the movements of the glottis cease. On slicing the upper part of the medulla oblongata instead of the lower, from before backward, the opening or yawning of the mouth ceases; another slice, and the dilatations of the nose are arrested, and the inspiratory movements of the trunk alone remain.

While the power of motion in each part seems thus to be dependent on isolated points of the medulla oblongata and the medulla spinalis, an indirect or connecting influence is admitted to take place between them and the remaining parts of the brain; and whatever may be its nature or extent in animals, there can be no doubt of its being so infinitely greater in man as to be essentially different; for none of these experiments can be made either artificially or accidentally on any one of these parts in him, without being productive of the ultimate if not almost immediate death of the whole.

Dr. Marshall Hall, in the comprehensive and luminous view he has taken of the nervous system, supposes that each sentient and motor nerve of the spinal marrow is further endowed with an excito-motor power for reflex action. He calls these generally excito-motor nerves, and considers them to be connected with a part of the medulla spinalis, distinct from that portion which is strictly an appendage to the brain. _Incident_ nerves arise from the skin and certain mucous membranes, and convey impressions from them to the spinal marrow. _Reflex_ nerves convey back the nervous influence excited through the medium of the incident nerves, to the voluntary muscles in which they terminate; and Dr. Marshall Hall further considers that these nerves, and the part he calls the true spinal cord, constitute the true spinal system which presides over ingestion and exclusion, retention and egestion; and consequently that its influence is exerted upon the muscles which belong to the entrances and outlets of the animal frame; or, in other words, upon the sphincters, and the muscles of deglutition and of respiration; and that the true spinal system maintains the tone of the whole muscular system. Stimulating an incident or excitor nerve of the extremities, by tickling or pricking the sole of the foot or the palm of the hand after sensation is apparently destroyed, causes a special muscular contraction or motion in the limb, if the excito-motor system be uninjured. Irritating the eyelashes induces contraction of the eyelids; and the irritation of one will sometimes cause contraction of both. Tickling the verge of the anus induces contraction of the sphincter muscle. Irritating the fauces and the root of the tongue, by pressing it down with the handle of a spoon, induces an action of deglutition. Respiration is excited by irritating or exciting the trifacial or fifth pair of nerves, by throwing cold water on the face, and stimulating the nostrils; by influencing the spinal nerves by a similar use of cold water to the body and chest, and by tickling or stimulating the sides, soles of the feet, and verge of the anus.

The great object or value of these and other facts and physiological experiments is to enable us to conclude, as far as possible, what part, what great division of the brain or spinal marrow is most seriously injured, more particularly with respect to the prognosis than to the treatment. Great severity and persistence of the symptoms lead to the belief that the part of the brain or spinal marrow on which they depend is directly injured rather than indirectly affected, and that the result is more likely to be fatal. Permanent insensibility and loss of motion may depend on cerebral mischief only. The loss of the mobility of the iris implies an affection of the tubercula quadrigemina. Convulsions, vomiting, a drawing up of the limb not affected by paralysis, stertor, a difficulty in swallowing, strabismus, and relaxed sphincters, show derangement of the spinal functions; which is well marked when tickling the eyelashes does not cause closing of the lid, of the verge of the anus no contraction of the sphincter, of the sole of the foot no motion of the toes.

245. In order to simplify the investigation of Injuries of the Head, they have been divided into two great classes: one denominated Injuries from Concussion; the other, Injuries from Compression or Irritation of the Brain. By the term Concussion of the Brain, a certain indefinable something, or cause of evil which cannot be demonstrated, is understood to have taken place; the effect of which is often clearly proved by the almost instantaneous death of the individual, or by a succession of symptoms which quickly lead to his destruction. The term concussion is very aptly and forcibly illustrated by the homely but striking expression in use in the sister country, when a man has been suddenly killed by a fall on the head, “that the life has been shook out of him.” On a dissection of the brain in a pure case of this kind, no trace of injury or even of derangement of any part of it can be perceived. Life is extinct, but the brain is intact. The immaterial has been separated from the material part, by an injury apparently inflicted on the very seat of life, with as little apparent derangement of its structure as if death had occurred in a secondary manner from the abstraction of blood by a rupture of the heart.

Modern surgery has in fact added nothing to our information on the subject, perhaps from the peculiar difficulties of the case, which may not admit of removal in the present state of our knowledge; although all writers seem to coincide in opinion that a sudden stoppage of the circulation of the blood is the more immediate cause of death. That the positive shock communicated to the brain from one side to the other, and the repercussion which follows from its resiliency, are capable of giving rise to a direct and visible injury, is indisputable. It usually forms on what may be termed the edges of the hemispheres, which appear to be discolored, bruised, and sometimes torn, so as to have caused the term laceration to be given to this kind of injury. This mischief, however, is most commonly found in the examination of those persons who have survived the accident for some days, and is therefore only a predisposing cause of death.