The cystic lymphangioma, lymphatic cyst, or congenital cystic hygroma is most often met with in the neck—hydrocele of the neck; it is situated beneath the deep fascia, and projects either in front of or behind the sterno-mastoid muscle. It may attain a large size, the overlying skin and cyst wall may be so thin as to be translucent, and it has been known to cause serious impairment of respiration through pressing on the trachea. In the axilla also the cystic tumour may attain a considerable size (Fig. 76); less frequent situations are the groin, and the floor of the mouth, where it constitutes one form of ranula.

The nature of these swellings is to be recognised by their situation, by their having existed from infancy, and, if necessary, by drawing off some of the contents of the cyst through a fine needle. They are usually remarkably indolent, persisting often for a long term of years without change, and, like the haemangioma, they sometimes undergo spontaneous cicatrisation and cure. Sometimes the cystic tumour becomes infected and forms an abscess—another, although less desirable, method of cure. Those situated in the neck are most liable to suppurate, probably because of pyogenic organisms being brought to them by the lymphatics taking origin in the scalp, ear, or throat.

If operative interference is called for, the cysts may be tapped and injected with iodine, or excised; the operation for removal may entail a considerable dissection amongst the deeper structures at the root of the neck, and should not be lightly undertaken; parts left behind may be induced to cicatrise by inserting a tube of radium and leaving it for a few days.

Lymphangiomas are met with in the abdomen in the form of omental cysts.

DISEASES OF LYMPH GLANDS

Lymphadenitis.—Inflammation of lymph glands results from the advent of an irritant, usually bacterial or toxic, brought to the glands by the afferent lymph vessels. These vessels may share in the inflammation and be the seat of lymphangitis, or they may show no evidence of the passage of the noxa. It is exceptional for the irritant to reach the gland through the blood-stream.

A strain or other form of trauma is sometimes blamed for the onset of lymphadenitis, especially in the glands of the groin (bubo), but it is usually possible to discover some source of pyogenic infection which is responsible for the mischief, or to obtain a history of some antecedent infection such as gonorrhoea. It is possible for gonococci to lie latent in the inguinal glands for long periods, and only give rise to lymphadenitis if the glands be subsequently subjected to injury. The glands most frequently affected are those in the neck, axilla, and groin.

The characters of the lymphadenitis vary with the nature of the irritant. Sometimes it is mild and evanescent, as in the glandular enlargement in the neck which attends tonsillitis and other forms of sore throat. Sometimes it is more persistent, as in the enlargement that is associated with adenoids, hypertrophied tonsils, carious teeth, eczema of the scalp, and otorrhoea; and it is possible that this indolent enlargement predisposes to tuberculous infection. A similar enlargement is met with in the axilla in cases of chronic interstitial mastitis, and in the groin as a result of chronic irritation about the external genitals, such as balanitis.

Sometimes the lymphadenitis is of an acute character, and the tendency is towards the formation of an abscess. This is illustrated in the axillary glands as a result of infected wounds of the fingers; in the femoral glands in infected wounds or purulent blisters on the foot; in the inguinal glands in gonorrhoea and soft sore; and in the cervical glands in the severer forms of sore throat associated with diphtheria and scarlet fever. The most acute suppurations result from infection with streptococci.

Superficial glands, when inflamed and suppurating, become enlarged, tender, fixed, and matted to one another. In the glands of the groin the suppurative process is often remarkably sluggish; purulent foci form in the interior of individual glands, and some time may elapse before the pus erupts through their respective capsules. In the deeply placed cervical glands, especially in cases of streptococcal throat infections, the suppuration rapidly involves the surrounding cellular tissue, and the clinical features are those of an acute cellulitis and deeply seated abscess. When this is incised the necrosed glands may be found lying in the pus, and on bacteriological examination are found to be swarming with streptococci. In suppuration of the axillary glands the abscess may be quite superficial, or it may be deeply placed beneath the strong fascia and pectoral muscles, according to the group of glands involved.

The diagnosis of septic lymphadenitis is usually easy. The indolent enlargements are not always to be distinguished, however, from commencing tuberculous disease, except by the use of the tuberculin test, and by the fact that they usually disappear on removing the peripheral source of irritation.

Treatment.—The first indication is to discover and deal with the source of infection, and in the indolent forms of lymphadenitis this will usually be followed by recovery. In the acute forms following on pyogenic infection, the best results are obtained from the hyperaemic treatment carried out by means of suction bells. If suppuration is not thereby prevented, or if it has already taken place, each separate collection of pus is punctured with a narrow-bladed knife and the use of the suction bell is persevered with. If there is a large periglandular abscess, as is often the case, in the neck and axilla, the opening may require to be made by Hilton's method, and it may be necessary to insert a drainage-tube.



Tuberculous Disease of Glands.—This is a disease of great frequency and importance. The tubercle bacilli usually gain access to the gland through the afferent lymph vessels, which convey them from some lesion of the surface within the area drained by them. Tuberculous infection may supervene in glands that are already enlarged as a result of chronic septic irritation. While any of the glands in the body may be affected, the disease is most often met with in the cervical groups which derive their lymph from the mouth, nose, throat, and ear.

The appearance of the glands on section varies with the stage of the disease. In the early stages the gland is enlarged, it may be to many times its natural size, is normal in appearance and consistence, and as there is no peri-adenitis it is easily shelled out from its surroundings. On microscopical examination, however, there is evidence of infection in the shape of bacilli and of characteristic giant and epithelioid cells. At a later stage, the gland tissue is studded with minute yellow foci which tend to enlarge and in time to become confluent, so that the whole gland is ultimately converted into a caseous mass. This caseous material is surrounded by the thickened capsule which, as a result of peri-adenitis, tends to become adherent to and fused with surrounding structures, and particularly with layers of fascia and with the walls of veins. The caseated tissue often remains unchanged for long periods; it may become calcified, but more frequently it breaks down and liquefies.

Tuberculous disease in the cervical glands is a common accompaniment or sequel of adenoids, enlarged tonsils, carious teeth, pharyngitis, middle-ear disease, and conjunctivitis. These lesions afford the bacilli a chance of entry into the lymph vessels, in which they are carried to the glands, where they give rise to disease.

The enlargement may affect only one gland, usually below the angle of the mandible, and remain confined to it, the gland reaching the size of a hazel-nut, and being ovoid, firm, and painless. More commonly the disease affects several glands, on one or on both sides of the neck. When the disease commences in the pre-auricular or submaxillary glands, it tends to spread to those along the carotid sheath: when the posterior auricular and occipital glands are first involved, the spread is to those along the posterior border of the sterno-mastoid. In many cases all the chains in front of, beneath, and behind this muscle are involved, the enlarged glands extending from the mastoid to the clavicle. They are at first discrete and movable, and may even vary in size from time to time; but with the addition of peri-adenitis they become fixed and matted together, forming lobulated or nodular masses (Fig. 78). They become adherent not only to one another, but also to the structures in their vicinity,—and notably to the internal jugular vein,—a point of importance in regard to their removal by operation.

At any stage the disease may be arrested and the glands remain for long periods without further change. It is possible that the tuberculous tissue may undergo cicatrisation. More commonly suppuration ensues, and a cold abscess forms, but if there is a mixed infection, the pyogenic factor being usually derived from the throat, it may take on active features.



The transition from the solid to the liquefied stage is attended with pain and tenderness in the gland, which at the same time becomes fixed and globular, and finally fluctuation can be elicited.

If left to itself, the softened tubercle erupts through the capsule of the gland and infects the cellular tissue. The cervical fascia is perforated and a cold abscess, often much larger than the gland from which it took origin, forms between the fascia and the overlying skin. The further stages—reddening, undermining of skin and external rupture, with the formation of ulcers and sinuses—have been described with tuberculous abscess. The ulcers and sinuses persist indefinitely, or they heal and then break out again; sometimes the skin becomes infected, and a condition like lupus spreads over a considerable area. Spontaneous healing finally takes place after the caseous tubercle has been extruded; the resulting scars are extremely unsightly, being puckered or bridled, or hypertrophied like keloid.

While the disease is most common in childhood and youth, it may be met with even in advanced life; and although often associated with impaired health and unhealthy surroundings, it may affect those who are apparently robust and are in affluent circumstances.

Diagnosis.—The chief importance lies in differentiating tuberculous disease from lympho-sarcoma and from lymphadenoma, and this is usually possible from the history and from the nature of the enlargement. Signs of liquefaction and suppuration support the diagnosis of tubercle. If any doubt remains, one of the glands should be removed and submitted to microscopical examination. Other forms of sarcoma, and the enlargement of an accessory thyreoid, are less likely to be confused with tuberculous glands. Calcified tuberculous glands give definite shadows with the X-rays.

Enlargement of the cervical glands from secondary cancer may simulate tuberculosis, but is differentiated by its association with cancer in the mouth or throat, and by the characteristic, stone-like induration of epithelioma.

The cold abscess which results from tuberculous glands is to be distinguished from that due to disease in the cervical spine, retro-pharyngeal abscess, as well as from congenital and other cystic swellings in the neck.

Prognosis.—Next to lupus, glandular disease is of all tuberculous lesions the least dangerous to life; but while it is the rule to recover from tuberculous disease of glands with or without an operation, it is unfortunately quite common for such persons to become the subjects of tuberculosis in other parts of the body at any subsequent period of life.

Treatment.—There is considerable difference of opinion regarding the treatment of glandular tuberculosis. Some authorities, impressed with the undoubted possibility of natural cure, are satisfied with promoting this by measures directed towards improving the general health, by the prolonged administration of tuberculin, and by repeated exposures to the X-rays and to sunlight. Others again, influenced by the risk of extension of the disease and by the destruction of tissue and disfigurement caused by breaking down of the tuberculous tissue and mixed infection, advocate the removal of the glands by operation.

The conditions vary widely in different cases, and the treatment should be adapted to the individual requirements. If the disease remains confined to the glands originally infected and there are no signs of breaking down, "expectant measures" may be persevered with.



If, on the other hand, the disease exhibits aggressive tendencies, the question of operation should be considered. The undesirable results of the breaking down and liquefaction of the diseased gland may be avoided by the timely withdrawal of the fluid contents through a hollow needle.

The excision of tuberculous glands is often a difficult operation, because of the number and deep situation of the glands to be removed, and of the adhesions to surrounding structures. The skin incision must be sufficiently extensive to give access to the whole of the affected area, and to avoid disfigurement should, whenever possible, be made in the line of the natural creases of the skin. In exposing the glands the common facial and other venous trunks may require to be clamped and tied. Care must be taken not to injure the important nerves, particularly the accessory, the vagus, and the phrenic. The inframaxillary branches of the facial, the hypoglossal and its descending branches, and the motor branches of the deep cervical plexus, are also liable to be injured. The dissection is rendered easier and is attended with less risk of injury to the nerves, if the patient is placed in the sitting posture so as to empty the veins, and, instead of a knife, the conical scissors of Mayo are employed. When the glands are extensively affected on both sides of the neck, it is advisable to allow an interval to elapse rather than to operate on both sides at one sitting. (Op. Surg., p. 189.)

If the tonsils are enlarged they should not be removed at the same time, as, by so doing, there is a risk of pyogenic infection from the throat being carried to the wound in the neck, but they should be removed, after an interval, to prevent relapse of disease in the glands.

When the skin is broken and caseous tuberculous tissue is exposed, healing is promoted by cutting away diseased skin, removing the granulation tissue with the spoon, scraping sinuses, and packing the cavity with iodoform worsted and treating it by the open method and secondary suture if necessary. Exposure to the sunshine on the seashore and to the X-rays is often beneficial in these cases.

Tuberculous disease in the axillary glands may be a result of extension from those in the neck, from the mamma, ribs, or sternum, or more rarely from the upper extremity. We have seen it from an infected wound of a finger. In some cases no source of infection is discoverable. The individual glands attain a considerable size, and they fuse together to form a large tumour which fills up the axillary space. The disease progresses more rapidly than it does in the cervical glands, and almost always goes on to suppuration with the formation of sinuses. Conservative measures need not be considered, as the only satisfactory treatment is excision, and that without delay.

Tuberculous disease in the glands of the groin is comparatively rare. We have chiefly observed it in the femoral glands as a result of inoculation tubercle on the toes or sole of the foot. The affected glands nearly always break down and suppurate, and after destroying the overlying skin give rise to fungating ulcers. The treatment consists in excising the glands and the affected skin. The dissection may be attended with troublesome haemorrhage from the numerous veins that converge towards the femoral trunk.

Tuberculous disease in the mesenteric and bronchial glands is described with the surgery of regions.

Syphilitic Disease of Glands.—Enlargement of lymph glands is a prominent feature of acquired syphilis, especially in the form of the indolent or bullet-bubo which accompanies the primary lesion, and the general enlargement of glands that occurs in secondary syphilis. Gummatous disease in glands is extremely rare; the affected gland rapidly enlarges to the size of a walnut, and may then persist for a long period without further change; if it breaks down, the overlying skin is destroyed and the caseated tissue of the gumma exposed.

Lymphadenoma.—Hodgkin's Disease (Pseudo-leukaemia of German authors).—This is a rare disease, the origin of which is as yet unknown, but analogy would suggest that it is due to infection with a slowly growing micro-organism. It is chiefly met with in young subjects, and is characterised by a painless enlargement of a particular group of glands, most commonly those in the cervical region (Fig. 80).



The glands are usually larger than in tuberculosis, and they remain longer discrete and movable; they are firm in consistence, and on section present a granular appearance due to overgrowth of the connective-tissue framework. In time the glandular masses may form enormous projecting tumours, the swelling being added to by lymphatic oedema of the overlying cellular tissue and skin.

The enlargement spreads along the chain of glands to those above the clavicle, to those in the axilla, and to those of the opposite side (Fig. 81). Later, the glands in the groin become enlarged, and it is probable that the infection has spread from the neck along the mediastinal, bronchial, retro-peritoneal, and mesenteric glands, and has branched off to the iliac and inguinal groups.

Two clinical types are recognised, one in which the disease progresses slowly and remains confined to the cervical glands for two or more years; the other, in which the disease is more rapidly disseminated and causes death in from twelve to eighteen months.



In the acute form, the health suffers, there is fever, and the glands may vary in size with variations in the temperature; the blood presents the characters met with in secondary anaemia. The spleen, liver, testes, and mammae may be enlarged; the glandular swellings press on important structures, such as the trachea, oesophagus, or great veins, and symptoms referable to such pressure manifest themselves.

Diagnosis.—Considerable difficulty attends the diagnosis of lymphadenoma at an early stage. The negative results of tuberculin tests may assist in the differentiation from tuberculous disease, but the more certain means of excising one of the suspected glands and submitting it to microscopical examination should be had recourse to. The sections show proliferation of endothelial cells, the formation of numerous giant cells quite unlike those of tuberculosis and a progressive fibrosis. Lympho-sarcoma can usually be differentiated by the rapid assumption of the local features of malignant disease, and in a gland removed for examination, a predominance of small round cells with scanty protoplasm. The enlargement associated with leucocythaemia is differentiated by the characteristic changes in the blood.

Treatment.—In the acute form of lymphadenoma, treatment is of little avail. Arsenic may be given in full doses either by the mouth or by subcutaneous injection; the intravenous administration of neo-salvarsan may be tried. Exposure to the X-rays and to radium has been more successful than any other form of treatment. Excision of glands, although sometimes beneficial, seldom arrests the progress of the disease. The ease and rapidity with which large masses of glands may be shelled out is in remarkable contrast to what is observed in tuberculous disease. Surgical interference may give relief when important structures are being pressed upon—tracheotomy, for example, may be required where life is threatened by asphyxia.

Leucocythaemia.—This is a disease of the blood and of the blood-forming organs, in which there is a great increase in the number, and an alteration of the character, of the leucocytes present in the blood. It may simulate lymphadenoma, because, in certain forms of the disease, the lymph glands, especially those in the neck, axilla, and groin, are greatly enlarged.

TUMOURS OF LYMPH GLANDS

Primary Tumours.—Lympho-sarcoma, which may be regarded as a sarcoma starting in a lymph gland, appears in the neck, axilla, or groin as a rapidly growing tumour consisting of one enlarged gland with numerous satellites. As the tumour increases in size, the sarcomatous tissue erupts through the capsule of the gland, and infiltrates the surrounding tissues, whereby it becomes fixed to these and to the skin.



The prognosis is grave in the extreme, and the only hope is in early excision, followed by the use of radium and X-rays. We have observed a case of lympho-sarcoma above the clavicle, in which excision of all that was removable, followed by the insertion of a tube of radium for ten days, was followed by a disappearance of the disease over a period which extended to nearly five years, when death resulted from a tumour in the mediastinum. In a second case in which the growth was in the groin, the patient, a young man, remained well for over two years and was then lost sight of.

Secondary Tumours.—Next to tuberculosis, secondary cancer is the most common disease of lymph glands. In the neck it is met with in association with epithelioma of the lip, tongue, or fauces. The glands form tumours of variable size, and are often larger than the primary growth, the characters of which they reproduce. The glands are at first movable, but soon become fixed both to each other and to their surroundings; when fixed to the mandible they form a swelling of bone-like hardness; in time they soften, liquefy, and burst through the skin, forming foul, fungating ulcers. A similar condition is met with in the groin from epithelioma of the penis, scrotum, or vulva. In cancer of the breast, the infection of the axillary glands is an important complication.

In pigmented or melanotic cancers of the skin, the glands are early infected and increase rapidly, so that, when the primary growth is still of small size—as, for example, on the sole of the foot—the femoral glands may already constitute large pigmented tumours.



The implication of the glands in other forms of cancer will be considered with regional surgery.

Secondary sarcoma is seldom met with in the lymph glands except when the primary growth is a lympho-sarcoma and is situated in the tonsil, thyreoid, or testicle.



CHAPTER XVI

THE NERVES

Anatomy—INJURIES OF NERVES: Changes in nerves after division; Repair and its modifications; Clinical features; Primary and secondary suture—SUBCUTANEOUS INJURIES OF NERVES—DISEASES: Neuritis; Tumours—Surgery of the individual nerves: Brachial neuralgia; Sciatica; Trigeminal neuralgia.

Anatomy.—A nerve-trunk is made up of a variable number of bundles of nerve fibres surrounded and supported by a framework of connective tissue. The nerve fibres are chiefly of the medullated type, and they run without interruption from a nerve cell or neuron in the brain or spinal medulla to their peripheral terminations in muscle, skin, and secretory glands.

Each nerve fibre consists of a number of nerve fibrils collected into a central bundle—the axis cylinder—which is surrounded by an envelope, the neurolemma or sheath of Schwann. Between the neurolemma and the axis cylinder is the medullated sheath, composed of a fatty substance known as myelin. This medullated sheath is interrupted at the nodes of Ranvier, and in each internode is a nucleus lying between the myelin and the neurolemma. The axis cylinder is the essential conducting structure of the nerve, while the neurolemma and the myelin act as insulating agents. The axis cylinder depends for its nutrition on the central neuron with which it is connected, and from which it originally developed, and it degenerates if it is separated from its neuron.

The connective-tissue framework of a nerve-trunk consists of the perineurium, or general sheath, which surrounds all the bundles; the epineurium, surrounding individual groups of bundles; and the endoneurium, a delicate connective tissue separating the individual nerve fibres. The blood vessels and lymphatics run in these connective-tissue sheaths.

According to Head and his co-workers, Sherren and Rivers, the afferent fibres in the peripheral nerves can be divided into three systems:—

1. Those which subserve deep sensibility and conduct the impulses produced by pressure as well as those which enable the patient to recognise the position of a joint on passive movement (joint-sensation), and the kinaesthetic sense, which recognises that active contraction of the muscle is taking place (active muscle-sensation). The fibres of this system run with the motor nerves, and pass to muscles, tendons, and joints. Even division of both the ulnar and the median nerves above the wrist produces little loss of deep sensibility, unless the tendons are also cut through. The failure to recognise this form of sensibility has been largely responsible for the conflicting statements as to the sensory phenomena following operations for the repair of divided nerves.

2. Those which subserve protopathic sensibility—that is, are capable of responding to painful cutaneous stimuli and to the extremes of heat and cold. These also endow the hairs with sensibility to pain. They are the first to regenerate after division.

3. Those which subserve epicritic sensibility, the most highly specialised, capable of appreciating light touch, e.g. with a wisp of cotton wool, as a well-localised sensation, and the finer grades of temperature, called cool and warm (72-104 F.), and of discriminating as separate the points of a pair of compasses 2 cms. apart. These are the last to regenerate.

A nerve also exerts a trophic influence on the tissues in which it is distributed.

The researches of Stoffel on the minute anatomy of the larger nerves, and the disposition in them of the bundles of nerve fibres supplying different groups of muscles, have opened up what promises to be a fruitful field of clinical investigation and therapeutics. He has shown that in the larger nerve-trunks the nerve bundles for special groups of muscles are not, as was formerly supposed, arranged irregularly and fortuitously, but that on the contrary the nerve fibres to a particular group of muscles have a typical and practically constant position within the nerve.

In the large nerve-trunks of the limbs he has worked out the exact position of the bundles for the various groups of muscles, so that in a cross section of a particular nerve the component bundles can be labelled as confidently and accurately as can be the cortical areas in the brain. In the living subject, by using a fine needle-like electrode and a very weak galvanic current, he has been able to differentiate the nerve bundles for the various groups of muscles. In several cases of spastic paralysis he succeeded in picking out in the nerve-trunk of the affected limb the nerve bundles supplying the spastic muscles, and, by resecting portions of them, in relieving the spasm. In a case of spastic contracture of the pronator muscles of the forearm, for example, an incision is made along the line of the median nerve above the bend of the elbow. At the lateral side of the median nerve, where it lies in contact with the biceps muscle, is situated a well-defined and easily isolated bundle of fibres which supplies the pronator teres, the flexor carpi radialis, and the palmaris longus muscles. On incising the sheath of the nerve this bundle can be readily dissected up and its identity confirmed by stimulating it with a very weak galvanic current. An inch or more of the bundle is then resected.

INJURIES OF NERVES

Nerves are liable to be cut or torn across, bruised, compressed, stretched, or torn away from their connections with the spinal medulla.

Complete Division of a Mixed Nerve.—Complete division is a common result of accidental wounds, especially above the wrist, where the ulnar, median, and radial nerves are frequently cut across, and in gun-shot injuries.

Changes in Structure and Function.—The mere interruption of the continuity of a nerve results in degeneration of its fibres, the myelin being broken up into droplets and absorbed, while the axis cylinders swell up, disintegrate, and finally disappear. Both the conducting and the insulating elements are thus lost. The degeneration in the central end of the divided nerve is usually limited to the immediate proximity of the lesion, and does not even involve all the nerve fibres. In the distal end, it extends throughout the entire peripheral distribution of the nerve, and appears to be due to the cutting off of the fibres from their trophic nerve cells in the spinal medulla. Immediate suturing of the ends does not affect the degeneration of the distal segment. The peripheral end undergoes complete degeneration in from six weeks to two months.

The physiological effects of complete division are that the muscles supplied by the nerve are immediately paralysed, the area to which it furnishes the sole cutaneous supply becomes insensitive, and the other structures, including tendons, bones, and joints, lose sensation, and begin to atrophy from loss of the trophic influence.

Nerves divided in Amputation.—In the case of nerves divided in an amputation, there is an active, although necessarily abortive, attempt at regeneration, which results in the formation of bulbous swellings at the cut ends of the nerves. When there has been suppuration, and especially if the nerves have been cut so as to be exposed in the wound, these bulbous swellings may attain an abnormal size, and are then known as "amputation" or "stump neuromas" (Fig. 84).

When the nerves in a stump have not been cut sufficiently short, they may become involved in the cicatrix, and it may be necessary, on account of pain, to free them from their adhesions, and to resect enough of the terminal portions to prevent them again becoming adherent. When this is difficult, a portion may be resected from each of the nerve-trunks at a higher level; and if this fails to give relief, a fresh amputation may be performed. When there is agonising pain dependent upon an ascending neuritis, it may be necessary to resect the corresponding posterior nerve roots within the vertebral canal.



Other Injuries of Nerves.—Contusion of a nerve-trunk is attended with extravasation of blood into the connective-tissue sheaths, and is followed by degeneration of the contused nerve fibres. Function is usually restored, the conducting paths being re-established by the formation of new nerve fibres.

When a nerve is torn across or badly crushed—as, for example, by a fractured bone—the changes are similar to those in a divided nerve, and the ultimate result depends on the amount of separation between the ends and the possibility of the young axis cylinders bridging the gap.

Involvement of Nerves in Scar Tissue.—Pressure or traction may be exerted upon a nerve by contracting scar tissue, or a process of neuritis or perineuritis may be induced.

When terminal filaments are involved in a scar, it is best to dissect out the scar, and along with it the ends of the nerves pressed upon. When a nerve-trunk, such as the sciatic, is involved in cicatricial tissue, the nerve must be exposed and freed from its surroundings (neurolysis), and then stretched so as to tear any adhesions that may be present above or below the part exposed. It may be advisable to displace the liberated nerve from its original position so as to minimise the risk of its incorporation in the scar of the original wound or in that resulting from the operation—for example, the radial nerve may be buried in the substance of the triceps, or it may be surrounded by a segment of vein or portion of fat-bearing fascia.

Injuries of nerves resulting from gun-shot wounds include: (1) those in which the nerve is directly damaged by the bullet, and (2) those in which the nerve-trunk is involved secondarily either by scar tissue in its vicinity or by callus following fracture of an adjacent bone. The primary injuries include contusion, partial or complete division, and perforation of the nerve-trunk. One of the most constant symptoms is the early occurrence of severe neuralgic pain, and this is usually associated with marked hyperaesthesia.

Regeneration.—Process of Repair when the Ends are in Contact.—If the wound is aseptic, and the ends of the divided nerve are sutured or remain in contact, they become united, and the conducting paths are re-established by a regeneration of nerve fibres. There is a difference of opinion as to the method of regeneration. The Wallerian doctrine is that the axis cylinders in the central end grow downwards, and enter the nerve sheaths of the distal portion, and continue growing until they reach the peripheral terminations in muscle and skin, and in course of time acquire a myelin sheath; the cells of the neurolemma multiply and form long chains in both ends of the nerve, and are believed to provide for the nourishment and support of the actively lengthening axis cylinders. Another view is that the formation of new axis cylinders is not confined to the central end, but that it goes on also in the peripheral segment, in which, however, the new axis cylinders do not attain maturity until continuity with the central end has been re-established.

If the wound becomes infected and suppuration occurs, the young nerve fibres are destroyed and efficient regeneration is prevented; the formation of scar tissue also may constitute a permanent obstacle to new nerve fibres bridging the gap.

When the ends are not in contact, reunion of the divided nerve fibres does not take place whether the wound is infected or not. At the proximal end there forms a bulbous swelling, which becomes adherent to the scar tissue. It consists of branching axis cylinders running in all directions, these having failed to reach the distal end because of the extent of the gap. The peripheral end is completely degenerated, and is represented by a fibrous cord, the cut end of which is often slightly swollen or bulbous, and is also incorporated with the scar tissue of the wound.

Clinical Features.—The symptoms resulting from division and non-union of a nerve-trunk necessarily vary with the functions of the affected nerve. The following description refers to a mixed sensori-motor trunk, such as the median or radial (musculo-spiral) nerve.

Sensory Phenomena.—Superficial touch is tested by means of a wisp of cotton wool stroked gently across the skin; the capacity of discriminating two points as separate, by a pair of blunt-pointed compasses; the sensation of pressure, by means of a pencil or other blunt object; of pain, by pricking or scratching with a needle; and of sensibility to heat and cold, by test-tubes containing water at different temperatures. While these tests are being carried out, the patient's eyes are screened off.

After division of a nerve containing sensory fibres, there is an area of absolute cutaneous insensibility to touch (anaesthesia), to pain (analgesia), and to all degrees of temperature—loss of protopathic sensibility; surrounded by an area in which there is loss of sensation to light touch, inability to recognise minor differences of temperature (72-104 F.), and to appreciate as separate impressions the contact of the two points of a compass—loss of epicritic sensibility (Head and Sherren) (Figs. 91, 92).

Motor Phenomena.—There is immediate and complete loss of voluntary power in the muscles supplied by the divided nerve. The muscles rapidly waste, and within from three to five days, they cease to react to the faradic current. When tested with the galvanic current, it is found that a stronger current must be used to call forth contraction than in a healthy muscle, and the contraction appears first at the closing of the circuit when the anode is used as the testing electrode. The loss of excitability to the interrupted current, and the specific alteration in the type of contraction with the constant current, is known as the reaction of degeneration. After a few weeks all electric excitability is lost. The paralysed muscles undergo fatty degeneration, which attains its maximum three or four months after the division of the nerve. Further changes may take place, and result in the transformation of the muscle into fibrous tissue, which by undergoing shortening may cause deformity known as paralytic contracture.

Vaso-motor Phenomena.—In the majority of cases there is an initial rise in the temperature of the part (2 to 3 F.), with redness and increased vascularity. This is followed by a fall in the local temperature, which may amount to 8 or 10 F., the parts becoming pale and cold. Sometimes the hyperaemia resulting from vaso-motor paralysis is more persistent, and is associated with swelling of the parts from oedema—the so-called angio-neurotic oedema. The vascularity varies with external influences, and in cold weather the parts present a bluish appearance.

Trophic Phenomena.—Owing to the disappearance of the subcutaneous fat, the skin is smooth and thin, and may be abnormally dry. The hair is harsh, dry, and easily shed. The nails become brittle and furrowed, or thick and curved, and the ends of the fingers become club-shaped. Skin eruptions, especially in the form of blisters, occur, or there may be actual ulcers of the skin, especially in winter. In aggravated cases the tips of the fingers disappear from progressive ulceration, and in the sole of the foot a perforating ulcer may develop. Arthropathies are occasionally met with, the joints becoming the seat of a painless effusion or hydrops, which is followed by fibrous thickening of the capsular and other ligaments, and terminates in stiffness and fibrous ankylosis. In this way the fingers are seriously crippled and deformed.

Treatment of Divided Nerves.—The treatment consists in approximating the divided ends of the nerve and placing them under the most favourable conditions for repair, and this should be done at the earliest possible opportunity. (Op. Surg., pp. 45, 46.)

Primary Suture.—The reunion of a recently divided nerve is spoken of as primary suture, and for its success asepsis is essential. As the suturing of the ends of the nerve is extremely painful, an anaesthetic is required.

When the wound is healed and while waiting for the restoration of function, measures are employed to maintain the nutrition of the damaged nerve and of the parts supplied by it. The limb is exercised, massaged, and douched, and protected from cold and other injurious influences. The nutrition of the paralysed muscles is further improved by electricity. The galvanic current is employed, using at first a mild current of not more than 5 milliamperes for about ten minutes, the current being made to flow downwards in the course of the nerve, with the positive electrode applied to the spine, and the negative over the affected nerve near its termination. It is an advantage to have a metronome in the circuit whereby the current is opened and closed automatically at intervals, so as to cause contraction of the muscles.

The results of primary suture, when it has been performed under favourable conditions, are usually satisfactory. In a series of cases investigated by Head and Sherren, the period between the operation and the first return of sensation averaged 65 days. According to Purves Stewart protopathic sensation commences to appear in about six weeks and is completely restored in six months; electric sensation and motor power reappear together in about six months, and restoration is complete in a year. When sensation returns, the area of insensibility to pain steadily diminishes and disappears; sensibility to extremes of temperature appears soon after; and last of all, after a considerable interval, there is simultaneous return of appreciation of light touch, moderate degrees of temperature, and the points of a compass.

A clinical means of estimating how regeneration in a divided nerve is progressing has been described by Tinel. He found that a tingling sensation, similar to that experienced in the foot, when it is recovering from the "sleeping" condition induced by prolonged pressure on the sciatic nerve from sitting on a hard bench, can be elicited on percussing over growing axis cylinders. Tapping over the proximal end of a newly divided nerve, e.g. the common peroneal behind the head of the fibula, produces no tingling, but when in about three weeks axis cylinders begin to grow in the proximal end-bulb, local tingling is induced by tapping there. The downward growth of the axis cylinders can be traced by tapping over the distal segment of the nerve, the tingling sensation being elicited as far down as the young axis cylinders have reached. When the regeneration of the axis cylinders is complete, tapping no longer causes tingling. It usually takes about one hundred days for this stage to be reached.

Tinel's sign is present before voluntary movement, muscular tone, or the normal electrical reactions reappear.

In cases of complete nerve paralysis that have not been operated upon, the tingling test is helpful in determining whether or not regeneration is taking place. Its detection may prevent an unnecessary operation being performed.

Primary suture should not be attempted so long as the wound shows signs of infection, as it is almost certain to end in failure. The ends should be sutured, however, as soon as the wound is aseptic or has healed.

Secondary Suture.—The term secondary suture is applied to the operation of stitching the ends of the divided nerve after the wound has healed.

Results of Secondary Suture.—When secondary suture has been performed under favourable conditions, the prognosis is good, but a longer time is required for restoration of function than after primary suture. Purves Stewart says protopathic sensation is sometimes observed much earlier than in primary suture, because partial regeneration of axis cylinders in the peripheral segment has already taken place. Sensation is recovered first, but it seldom returns before three or four months. There then follows an improvement or disappearance of any trophic disturbances that may be present. Recovery of motion may be deferred for long periods—rather because of the changes in the muscles than from want of conductivity in the nerve—and if the muscles have undergone complete degeneration, it may never take place at all. While waiting for recovery, every effort should be made to maintain the nutrition of the damaged nerve, and of the parts which it supplies.

When suture is found to be impossible, recourse must be had to other methods, known as nerve bridging and nerve implantation.

Incomplete Division of a Mixed Nerve.—The effects of partial division of a mixed nerve vary according to the destination of the nerve bundles that have been interrupted. Within their area of distribution the paralysis is as complete as if the whole trunk had been cut across. The uninjured nerve-bundles continue to transmit impulses with the result that there is a dissociated paralysis within the distribution of the affected nerve, some muscles continuing to act and to respond normally to electric stimulation, while others behave as if the whole nerve-trunk had been severed.

In addition to vasomotor and trophic changes, there is often severe pain of a burning kind (causalgia or thermalgia) which comes on about a fortnight after the injury and causes intense and continuous suffering which may last for months. Paroxysms of pain may be excited by the slightest touch or by heat, and the patient usually learns for himself that the constant application of cold wet cloths allays the pain. The thermalgic area sweats profusely.

Operative treatment is indicated where there is no sign of improvement within three months, when recovery is arrested before complete restoration of function is attained, or when thermalgic pain is excessive.

Subcutaneous Injuries of Nerves.—Several varieties of subcutaneous injuries of nerves are met with. One of the best known is the compression paralysis of the nerves of the upper arm which results from sleeping with the arm resting on the back of a chair or the edge of a table—the so-called "drunkard's palsy"; and from the pressure of a crutch in the axilla—"crutch paralysis." In some of these injuries, notably "drunkard's palsy," the disability appears to be due not to damage of the nerve, but to overstretching of the extensors of the wrist and fingers (Jones). A similar form of paralysis is sometimes met with from the pressure of a tourniquet, from tight bandages or splints, from the pressure exerted by a dislocated bone or by excessive callus, and from hyper-extension of the arm during anaesthesia.

In all these forms there is impaired sensation, rarely amounting to anaesthesia, marked muscular wasting, and diminution or loss of voluntary motor power, while—and this is a point of great importance—the normal electrical reactions are preserved. There may also develop trophic changes such as blisters, superficial ulcers, and clubbing of the tips of the fingers. The prognosis is usually favourable, as recovery is the rule within from one to three months. If, however, neuritis supervenes, the electrical reactions are altered, the muscles degenerate, and recovery may be retarded or may fail to take place.

Injuries which act abruptly or instantaneously are illustrated in the crushing of a nerve by the sudden displacement of a sharp-edged fragment of bone, as may occur in comminuted fractures of the humerus. The symptoms include perversion or loss of sensation, motor paralysis, and atrophy of muscles, which show the reaction of degeneration from the eighth day onwards. The presence of the reaction of degeneration influences both the prognosis and the treatment, for it implies a lesion which is probably incapable of spontaneous recovery, and which can only be remedied by operation.

The treatment varies with the cause and nature of the lesion. When, for example, a displaced bone or a mass of callus is pressing upon the nerve, steps must be taken to relieve the pressure, by operation if necessary. When there is reason to believe that the nerve is severely crushed or torn across, it should be exposed by incision, and, after removal of the damaged ends, should be united by sutures. When it is impossible to make a definite diagnosis as to the state of the nerve, it is better to expose it by operation, and thus learn the exact state of affairs without delay; in the event of the nerve being torn, the ends should be united by sutures.

Dislocation of Nerves.—This injury, which resembles the dislocation of tendons from their grooves, is seldom met with except in the ulnar nerve at the elbow, and is described with injuries of that nerve.

DISEASES OF NERVES

Traumatic Neuritis.—This consists in an overgrowth of the connective-tissue framework of a nerve, which causes irritation and pressure upon the nerve fibres, sometimes resulting in their degeneration. It may originate in connection with a wound in the vicinity of a nerve, as, for example, when the brachial nerves are involved in scar tissue subsequent to an operation for clearing out the axilla for cancer; or in contusion and compression of a nerve—for example, by the pressure of the head of the humerus in a dislocation of the shoulder. Some weeks or months after the injury, the patient complains of increasing hyperaesthesia and of neuralgic pains in the course of the nerve. The nerve is very sensitive to pressure, and, if superficial, may be felt to be swollen. The associated muscles are wasted and weak, and are subject to twitchings. There are also trophic disturbances. It is rare to have complete sensory and motor paralysis. The disease is commonest in the nerves of the upper extremity, and the hand may become crippled and useless.

Treatment.—Any constitutional condition which predisposes to neuritis, such as gout, diabetes, or syphilis, must receive appropriate treatment. The symptoms may be relieved by rest and by soothing applications, such as belladonna, ichthyol, or menthol, by the use of hot-air and electric baths, and in obstinate cases by blistering or by the application of Corrigan's button. When such treatment fails the nerve may be stretched, or, in the case of a purely sensory trunk, a portion may be excised. Local causes, such as involvement of the nerve in a scar or in adhesions, may afford indications for operative treatment.

Multiple Peripheral Neuritis.—Although this disease mainly comes under the cognizance of the physician, it may be attended with phenomena which call for surgical interference. In this country it is commonly due to alcoholism, but it may result from diabetes or from chronic poisoning with lead or arsenic, or from bacterial infections and intoxications such as occur in diphtheria, gonorrhoea, syphilis, leprosy, typhoid, influenza, beri-beri, and many other diseases.

It is, as a rule, widely distributed throughout the peripheral nerves, but the distribution frequently varies with the cause—the alcoholic form, for example, mainly affecting the legs, the diphtheritic form the soft palate and pharynx, and that associated with lead poisoning the forearms. The essential lesion is a degeneration of the conducting fibres of the affected nerves, and the prominent symptoms are the result of this. In alcoholic neuritis there is great tenderness of the muscles. When the legs are affected the patient may be unable to walk, and the toes may droop and the heel be drawn up, resulting in one variety of pes equino-varus. Pressure sores and perforating ulcer of the foot are the most important trophic phenomena.

Apart from the medical treatment, measures must be taken to prevent deformity, especially when the legs are affected. The bedclothes are supported by a cage, and the foot maintained at right angles to the leg by sand-bags or splints. When the disease is subsiding, the nutrition of the damaged nerves and muscles should be maintained by massage, baths, passive movements, and the use of the galvanic current. When deformity has been allowed to take place, operative measures may be required for its correction.

NEUROMA[5]

[5] We have followed the classification adopted by Alexis Thomson in his work On Neuroma, and Neuro-fibromatosis (Edinburgh: 1900).

Neuroma is a clinical term applied to all tumours, irrespective of their structure, which have their seat in nerves.

A tumour composed of newly formed nerve tissue is spoken of as a true neuroma; when ganglionic cells are present in addition to nerve fibres, the name ganglionic neuroma is applied. These tumours are rare, and are chiefly met with in the main cords or abdominal plexuses of the sympathetic system of children or young adults. They are quite insensitive, and their removal is only called for if they cause pain or show signs of malignancy.

A false neuroma is an overgrowth of the sheath of a nerve. This overgrowth may result in the formation of a circumscribed tumour, or may take the form of a diffuse fibromatosis.

The circumscribed or solitary tumour grows from the sheath of a nerve which is otherwise healthy, and it may be innocent or malignant.

The innocent form is usually fibrous or myxomatous, and is definitely encapsulated. It may become cystic as a result of haemorrhage or of myxomatous degeneration. It grows very slowly, is usually elliptical in shape, and the solid form is rarely larger than a hazel-nut. The nerve fibres may be spread out all round the tumour, or may run only on one side of it. When subcutaneous and related to the smaller unnamed cutaneous nerves, it is known as a painful subcutaneous nodule or tubercle. It is chiefly met with about the ankle, and most often in women. It is remarkably sensitive, even gentle handling causing intense pain, which usually radiates to the periphery of the nerve affected. When related to a deeper, named nerve-trunk, it is known as a trunk-neuroma. It is usually less sensitive than the "subcutaneous nodule," and rarely gives rise to motor symptoms unless it involves the nerve roots where they pass through bony canals.

A trunk-neuroma is recognised clinically by its position in the line of a nerve, by the fact that it is movable in the transverse axis of the nerve but not in its long axis, and by being unduly painful and sensitive.



Treatment.—If the tumour causes suffering it should be removed, preferably by shelling it out from the investing nerve sheath or capsule. In the subcutaneous nodule the nerve is rarely recognisable, and is usually sacrificed. When removal of the tumour is incomplete, a tube of radium should be inserted into the cavity, to prevent recurrence of the tumour in a malignant form.

The malignant neuroma is a sarcoma growing from the sheath of a nerve. It has the same characters and clinical features as the innocent variety, only it grows more rapidly, and by destroying the nerve fibres causes motor symptoms—jerkings followed by paralysis. The sarcoma tends to spread along the lymph spaces in the long axis of the nerve, as well as to implicate the surrounding tissues, and it is liable to give rise to secondary growths. The malignant neuroma is met with chiefly in the sciatic and other large nerves of the limbs.

The treatment is conducted on the same lines as sarcoma in other situations; the insertion of a tube of radium after removal of the tumour diminishes the tendency to recurrence; a portion of the nerve-trunk being sacrificed, means must be taken to bridge the gap. In inoperable cases it may be possible to relieve pain by excising a portion of the nerve above the tumour, or, when this is impracticable, by resecting the posterior nerve roots and their ganglia within the vertebral canal.

The so-called amputation neuroma has already been referred to (p. 344).

Diffuse or Generalised Neuro-Fibromatosis—Recklinghausen's Disease.—These terms are now used to include what were formerly known as "multiple neuromata," as well as certain other overgrowths related to nerves. The essential lesion is an overgrowth of the endoneural connective tissue throughout the nerves of both the cerebro-spinal and sympathetic systems. The nerves are diffusely and unequally thickened, so that small twigs may become enlarged to the size of the median, while at irregular intervals along their course the connective-tissue overgrowth is exaggerated so as to form tumour-like swellings similar to the trunk-neuroma already described. The tumours, which vary greatly in size and number—as many as a thousand have been counted in one case—are enclosed in a capsule derived from the perineurium. The fibromatosis may also affect the cranial nerves, the ganglia on the posterior nerve roots, the nerves within the vertebral canal, and the sympathetic nerves and ganglia, as well as the continuations of the motor nerves within the muscles. The nerve fibres, although mechanically displaced and dissociated by the overgrown endoneurium, undergo no structural change except when compressed in passing through a bony canal.

The disease probably originates before birth, although it may not make its appearance till adolescence or even till adult life. It is sometimes met with in several members of one family. It is recognised clinically by the presence of multiple tumours in the course of the nerves, and sometimes by palpable enlargement of the superficial nerve-trunks (Fig. 86). The tumours resemble the solitary trunk-neuroma, are usually quite insensitive, and many of them are unknown to the patient. As a result of injury or other exciting cause, however, one or other tumour may increase in size and become extremely sensitive; the pain is then agonising; it is increased by handling, and interferes with sleep. In these conditions, a malignant transformation of the fibroma into sarcoma is to be suspected. Motor disturbances are exceptional, unless in the case of tumours within the vertebral canal, which press on the spinal medulla and cause paraplegia.



Neuro-fibromatosis is frequently accompanied by pigmentation of the skin in the form of brown spots or patches scattered over the trunk.

The disease is often stationary for long periods. In progressive cases the patient becomes exhausted, and usually dies of some intercurrent affection, particularly phthisis. The treatment is restricted to relieving symptoms and complications; removal of one of the tumours is to be strongly deprecated.

In a considerable proportion of cases one of the multiple tumours takes on the characters of a malignant growth ("secondary malignant neuroma," Garre). This malignant transformation may follow upon injury, or on an unsuccessful attempt to remove the tumour. The features are those of a rapidly growing sarcoma involving a nerve-trunk, with agonising pain and muscular cramps, followed by paralysis from destruction of the nerve fibres. The removal of the tumour is usually followed by recurrence, so that high amputation is the only treatment to be recommended. Metastasis to internal organs is exceptional.



There are other types of neuro-fibromatosis which require brief mention.

The plexiform neuroma (Fig. 87) is a fibromatosis confined to the distribution of one or more contiguous nerves or of a plexus of nerves, and it may occur either by itself or along with multiple tumours of the nerve-trunks and with pigmentation of the skin. The clinical features are those of an ill-defined swelling composed of a number of tortuous, convoluted cords, lying in a loose areolar tissue and freely movable on one another. It is rarely the seat of pain or tenderness. It most often appears in the early years of life, sometimes in relation to a pigmented or hairy mole. It is of slow growth, may remain stationary for long periods, and has little or no tendency to become malignant. It is usually subcutaneous, and is frequently situated on the head or neck in the distribution of the trigeminal or superficial cervical nerves. There is no necessity for its removal, but this may be indicated because of disfigurement, especially on the face or scalp or because its bulk interferes with function. When involving the ophthalmic division of the trigeminus, for example, it may cause enlargement of the upper lid and proptosis, with danger to the function of the globe. The results of excision are usually satisfactory, even if the removal is not complete.



The cutaneous neuro-fibroma or molluscum fibrosum has been shown by Recklinghausen to be a soft fibroma related to the terminal filaments of one of the cutaneous nerves (Fig. 88). The disease appears in the form of multiple, soft, projecting tumours, scattered all over the body, except the palms of the hands and soles of the feet. The tumours are of all sizes, some being no larger than a pin's head, whilst many are as big as a filbert and a few even larger. Many are sessile and others are distinctly pedunculated, but all are covered with skin. They are mobile, soft to the touch, and of the consistence of firm fat. In exceptional cases one of the skin tumours may attain an enormous size and cause a hideous deformity, hanging down by its own weight in lobulated or folded masses (pachy-dermatocele). The treatment consists in removing the larger swellings. In some cases molluscum fibrosum is associated with pigmentation of the skin and with multiple tumours of the nerve-trunks. The small multiple tumours rarely call for interference.



Elephantiasis neuromatosa is the name applied by Virchow to a condition in which a limb is swollen and misshapen as a result of the extension of a neuro-fibromatosis to the skin and subcutaneous cellular tissue of the extremity as a whole (Fig. 89). It usually begins in early life without apparent cause, and it may be associated with multiple tumours of the nerve-trunks. The inconvenience caused by the bulk and weight of the limb may justify its removal.

SURGERY OF THE INDIVIDUAL NERVES[6]

[6] We desire here to acknowledge our indebtedness to Mr. James Sherren's work on Injuries of Nerves and their Treatment.

The Brachial Plexus.—Lesions of the brachial plexus may be divided into those above the clavicle and those below that bone.

In the supra-clavicular injuries, the violence applied to the head or shoulder causes over-stretching of the anterior branches (primary divisions) of the cervical nerves, the fifth, or the fifth and sixth being those most liable to suffer. Sometimes the traction is exerted upon the plexus from below, as when a man in falling from a height endeavours to save himself by clutching at some projection, and the lesion then mainly affects the first dorsal nerve. There is tearing of the nerve sheaths, with haemorrhage, but in severe cases partial or complete severance of nerve fibres may occur and these give way at different levels. During the healing process an excess of fibrous tissue is formed, which may interfere with regeneration.

Post-anaesthetic paralysis occurs in patients in whom, during the course of an operation, the arm is abducted and rotated laterally or extended above the head, causing over-stretching of the plexus, especially of the fifth, or fifth and sixth, anterior branches.

A cervical rib may damage the plexus by direct pressure, the part usually affected being the medial cord, which is made up of fibres from the eighth cervical and first dorsal nerves.

When a lesion of the plexus complicates a fracture of the clavicle, the nerve injury is due, not to pressure on or laceration of the nerves by fragments of bone, but to the violence causing the fracture, and this is usually applied to the point of the shoulder.

Penetrating wounds, apart from those met with in military practice, are rare.

In the infra-clavicular injuries, the lesion most often results from the pressure of the dislocated head of the humerus; occasionally from attempts made to reduce the dislocation by the heel-in-the-axilla method, or from fracture of the upper end of the humerus or of the neck of the scapula. The whole plexus may suffer, but more frequently the medial cord is alone implicated.

Clinical Features.—Three types of lesion result from indirect violence: the whole plexus; the upper-arm type; and the lower-arm type.

When the whole plexus is involved, sensibility is lost over the entire forearm and hand and over the lateral surface of the arm in its distal two-thirds. All the muscles of the arm, forearm, and hand are paralysed, and, as a rule, also the pectorals and spinati, but the rhomboids and serratus anterior escape. There is paralysis of the sympathetic fibres to the eye and orbit, with narrowing of the palpebral fissure, recession of the globe, and the pupil is slow to dilate when shaded from the light.

The upper-arm type—Erb-Duchenne paralysis—is that most frequently met with, and it is due to a lesion of the fifth anterior branch, or, it may be, also of the sixth. The position of the upper limb is typical: the arm and forearm hang close to the side, with the forearm extended and pronated; the deltoid, spinati, biceps, brachialis, and supinators are paralysed, and in some cases the radial extensors of the wrist and the pronator teres are also affected. The patient is unable to supinate the forearm or to abduct the arm, and in most cases to flex the forearm. He may, however, regain some power of flexing the forearm when it is fully pronated, the extensors of the wrist becoming feeble flexors of the elbow. There is, as a rule, no loss of sensibility, but complaint may be made of tickling and of pins-and-needles over the lateral aspect of the arm. The abnormal position of the limb may persist although the muscles regain the power of voluntary movement, and as the condition frequently follows a fall on the shoulder, great care is necessary in diagnosis, as the condition is apt to be attributed to an injury to the axillary (circumflex) nerve.

The lower-arm type of paralysis, associated with the name of Klumpke, is usually due to over-stretching of the plexus, and especially affects the anterior branch of the first dorsal nerve. In typical cases all the intrinsic muscles of the hand are affected, and the hand assumes the claw shape. Sensibility is usually altered over the medial side of the arm and forearm, and there is paralysis of the sympathetic.

Infra-clavicular injuries, as already stated, are most often produced by a sub-coracoid dislocation of the humerus; the medial cord is that most frequently injured, and the muscles paralysed are those supplied by the ulnar nerve, with, in addition, those intrinsic muscles of the hand supplied by the median. Sensibility is affected over the medial surface of the forearm and ulnar area of the hand. Injury of the lateral and posterior cords is very rare.

Treatment is carried out on the lines already laid down for nerve injuries in general. It is impossible to diagnose between complete and incomplete rupture of the nerve cords, until sufficient time has elapsed to allow of the establishment of the reaction of degeneration. If this is present at the end of fourteen days, operation should not be delayed. Access to the cords of the plexus is obtained by a dissection similar to that employed for the subclavian artery, and the nerves are sought for as they emerge from under cover of the scalenus anterior, and are then traced until the seat of injury is found. In the case of the first dorsal nerve, it may be necessary temporarily to resect the clavicle. The usual after-treatment must be persisted in until recovery ensues, and care must be taken that the paralysed muscles do not become over-stretched. The prognosis is less favourable in the supra-clavicular lesions than in those below the clavicle, which nearly always recover without surgical intervention.

In the brachial birth-paralysis met with in infants, the lesion is due to over-stretching of the plexus, and is nearly always of the Erb-Duchenne type. The injury is usually unilateral, it occurs with almost equal frequency in breech and in vertex presentations, and the left arm is more often affected than the right. The lesion is seldom recognised at birth. The first symptom noticed is tenderness in the supra-clavicular region, the child crying when this part is touched or the arm is moved. The attitude may be that of the Erb-Duchenne type, or the whole of the muscles of the upper limb may be flaccid, and the arm hangs powerless. A considerable proportion of the cases recover spontaneously. The arm is to be kept at rest, with the affected muscles relaxed, and, as soon as tenderness has disappeared, daily massage and passive movements are employed. The reaction of degeneration can rarely be satisfactorily tested before the child is three months old, but if it is present, an operation should be performed. After operation, the shoulder should be elevated so that no traction is exerted on the affected cords.

The long thoracic nerve (nerve of Bell), which supplies the serratus anterior, is rarely injured. In those whose occupation entails carrying weights upon the shoulder it may be contused, and the resulting paralysis of the serratus is usually combined with paralysis of the lower part of the trapezius, the branches from the third and fourth cervical nerves which supply this muscle also being exposed to pressure as they pass across the root of the neck. There is complaint of pain above the clavicle, and winging of the scapula; the patient is unable to raise the arm in front of the body above the level of the shoulder or to perform any forward pushing movements; on attempting either of these the winging of the scapula is at once increased. If the scapula is compared with that on the sound side, it is seen that, in addition to the lower angle being more prominent, the spine is more horizontal and the lower angle nearer the middle line. The majority of these cases recover if the limb is placed at absolute rest, the elbow supported, and massage and galvanism persevered with. If the paralysis persists, the sterno-costal portion of the pectoralis major may be transplanted to the lower angle of the scapula.

The long thoracic nerve may be cut across while clearing out the axilla in operating for cancer of the breast. The displacement of the scapula is not so marked as in the preceding type, and the patient is able to perform pushing movements below the level of the shoulder. If the reaction of degeneration develops, an operation may be performed, the ends of the nerve being sutured, or the distal end grafted into the posterior cord of the brachial plexus.

The Axillary (Circumflex) Nerve.—In the majority of cases in which paralysis of the deltoid follows upon an injury of the shoulder, it is due to a lesion of the fifth cervical nerve, as has already been described in injuries of the brachial plexus. The axillary nerve itself as it passes round the neck of the humerus is most liable to be injured from the pressure of a crutch, or of the head of the humerus in sub-glenoid dislocation, or in fracture of the neck of the scapula or of the humerus. In miners, who work for long periods lying on the side, the muscle may be paralysed by direct pressure on the terminal filaments of the nerve, and the nerve may also be involved as a result of disease in the sub-deltoid bursa.

The deltoid is wasted, and the acromion unduly prominent. In recent cases paralysis of the muscle is easily detected. In cases of long standing it is not so simple, because other muscles, the spinati, the clavicular fibres of the pectoral and the serratus, take its place and elevate the arm; there is always loss of sensation on the lateral aspect of the shoulder. There is rarely any call for operative treatment, as the paralysis is usually compensated for by other muscles.

When the supra-scapular nerve is contused or stretched in injuries of the shoulder, the spinati muscles are paralysed and wasted, the spine of the scapula is unduly prominent, and there is impairment in the power of abducting the arm and rotating it laterally.

The musculo-cutaneous nerve is very rarely injured; when cut across, there is paralysis of the coraco-brachialis, biceps, and part of the brachialis, but no movements are abolished, the forearm being flexed, in the pronated position, by the brachio-radialis and long radial extensor of the wrist; in the supinated position, by that portion of the brachialis supplied by the radial nerve. Supination is feebly performed by the supinator muscle. Protopathic and epicritic sensibility are lost over the radial side of the forearm.

Radial (Musculo-Spiral) Nerve.—From its anatomical relationships this trunk is more exposed to injury than any other nerve in the body. It is frequently compressed against the humerus in sleeping with the arm resting on the back of a chair, especially in the deep sleep of alcoholic intoxication (drunkard's palsy). It may be pressed upon by a crutch in the axilla, by the dislocated head of the humerus, or by violent compression of the arm, as when an elastic tourniquet is applied too tightly. The most serious and permanent injuries of this nerve are associated with fractures of the humerus, especially those from direct violence attended with comminution of the bone. The nerve may be crushed or torn by one of the fragments at the time of the injury, or at a later period may be compressed by callus.

Clinical Features.—Immediately after the injury it is impossible to tell whether the nerve is torn across or merely compressed. The patient may complain of numbness and tingling in the distribution of the superficial branch of the nerve, but it is a striking fact, that so long as the nerve is divided below the level at which it gives off the dorsal cutaneous nerve of the forearm (external cutaneous branch), there is no loss of sensation. When it is divided above the origin of the dorsal cutaneous branch, or when the dorsal branch of the musculo-cutaneous nerve is also divided, there is a loss of sensibility on the dorsum of the hand.

The motor symptoms predominate, the muscles affected being the extensors of the wrist and fingers, and the supinators. There is a characteristic "drop-wrist"; the wrist is flexed and pronated, and the patient is unable to dorsiflex the wrist or fingers (Fig. 90). If the hand and proximal phalanges are supported, the second and third phalanges may be partly extended by the interossei and lumbricals. There is also considerable impairment of power in the muscles which antagonise those that are paralysed, so that the grasp of the hand is feeble, and the patient almost loses the use of it; in some cases this would appear to be due to the median nerve having been injured at the same time.



If the lesion is high up, as it is, for example, in crutch paralysis, the triceps and anconeus may also suffer.

Treatment.—The slighter forms of injury by compression recover under massage, douching, and electricity. If there is drop-wrist, the hand and forearm are placed on a palmar splint, with the hand dorsiflexed to nearly a right angle, and this position is maintained until voluntary dorsiflexion at the wrist returns to the normal. Recovery is sometimes delayed for several months.

In the more severe injuries associated with fracture of the humerus and attended with the reaction of degeneration, it is necessary to cut down upon the nerve and free it from the pressure of a fragment of bone or from callus or adhesions. If the nerve is torn across, the ends must be sutured, and if this is impossible owing to loss of tissue, the gap may be bridged by a graft taken from the superficial branch of the radial nerve, or the ends may be implanted into the median.

Finally, in cases in which the paralysis is permanent and incurable, the disability may be relieved by operation. A fascial graft can be employed to act as a ligament permanently extending the wrist; it is attached to the third and fourth metacarpal bones distally and to the radius or ulna proximally. The flexor carpi radialis can then be joined up with the extensor digitorum communis by passing its tendon through an aperture in the interosseous membrane, or better still, through the pronator quadratus, as there is less likelihood of the formation of adhesions when the tendon passes through muscle than through interosseous membrane. The palmaris longus is anastomosed with the abductor pollicis longus (extensor ossis metacarpi pollicis), thus securing a fair amount of abduction of the thumb. The flexor carpi ulnaris may also be anastomosed with the common extensor of the fingers. The extensors of the wrist may be shortened, so as to place the hand in the position of dorsal flexion, and thus improve the attitude and grasp of the hand.

The superficial branch of the radial (radial nerve) and the deep branch (posterior interosseous), apart from suffering in lesions of the radial, are liable to be contused or torn is dislocation of the head of the radius, and in fracture of the neck of the bone. The deep branch may be divided as it passes through the supinator in operations on old fractures and dislocations in the region of the elbow. Division of the superficial branch in the upper two-thirds of the forearm produces no loss of sensibility; division in the lower third after the nerve has become associated with branches from the musculo-cutaneous is followed by a loss of sensibility on the radial side of the hand and thumb. Wounds on the dorsal surface of the wrist and forearm are often followed by loss of sensibility over a larger area, because the musculo-cutaneous nerve is divided as well, and some of the fibres of the lower lateral cutaneous branch of the radial.



The Median Nerve is most frequently injured in wounds made by broken glass in the region of the wrist. It may also be injured in fractures of the lower end of the humerus, in fractures of both bones of the forearm, and as a result of pressure by splints. After division at the elbow, there is impairment of mobility which affects the thumb, and to a less extent the index finger: the terminal phalanx of the thumb cannot be flexed owing to the paralysis of the flexor pollicis longus, and the index can only be flexed at its metacarpo-phalangeal joint by the interosseous muscles attached to it. Pronation of the forearm is feeble, and is completed by the weight of the hand. After division at the wrist, the abductor-opponens group of muscles and the two lateral lumbricals only are affected; the abduction of the thumb can be feebly imitated by the short extensor and the long abductor (ext. ossis metacarpi pollicis), while opposition may be simulated by contraction of the long flexor and the short abductor of the thumb; the paralysis of the two medial lumbricals produces no symptoms that can be recognised. It is important to remember that when the median nerve is divided at the wrist, deep touch can be appreciated over the whole of the area supplied by the nerve; the injury, therefore, is liable to be over looked. If, however, the tendons are divided as well as the nerve, there is insensibility to deep touch. The areas of epicritic and of protopathic insensibility are illustrated in Fig. 91. The division of the nerve at the elbow, or even at the axilla, does not increase the extent of the loss of epicritic or protopathic sensibility, but usually affects deep sensibility.



The Ulnar Nerve.—The most common injury of this nerve is its division in transverse accidental wounds just above the wrist. In the arm it may be contused, along with the radial, in crutch paralysis; in the region of the elbow it may be injured in fractures or dislocations, or it may be accidentally divided in the operation for excising the elbow-joint.

When it is injured at or above the elbow, there is paralysis of the flexor carpi ulnaris, the ulnar half of the flexor digitorum profundus, all the interossei, the two medial lumbricals, and the adductors of the thumb. The hand assumes a characteristic attitude: the index and middle fingers are extended at the metacarpo-phalangeal joints owing to paralysis of the interosseous muscles attached to them; the little and ring fingers are hyper-extended at these joints in consequence of the paralysis of the lumbricals; all the fingers are flexed at the inter-phalangeal joints, the flexion being most marked in the little and ring fingers—claw-hand or main en griffe. On flexing the wrist, the hand is tilted to the radial side, but the paralysis of the flexor carpi ulnaris is often compensated for by the action of the palmaris longus. The little and ring fingers can be flexed to a slight degree by the slips of the flexor sublimis attached to them and supplied by the median nerve; flexion of the terminal phalanx of the little finger is almost impossible. Adduction and abduction movements of the fingers are lost. Adduction of the thumb is carried out, not by the paralysed adductor pollicis, but the movement may be simulated by the long flexor and extensor muscles of the thumb. Epicritic sensibility is lost over the little finger, the ulnar half of the ring finger, and that part of the palm and dorsum of the hand to the ulnar side of a line drawn longitudinally through the ring finger and continued upwards. Protopathic sensibility is lost over an area which varies in different cases. Deep sensibility is usually lost over an area almost as extensive as that of protopathic insensibility.

When the nerve is divided at the wrist, the adjacent tendons are also frequently severed. If divided below the point at which its dorsal branch is given off, the sensory paralysis is much less marked, and the injury is therefore liable to be overlooked until the wasting of muscles and typical main en griffe ensue. The loss of sensibility after division of the nerve before the dorsal branch is given off resembles that after division at the elbow, except that in uncomplicated cases deep sensibility is usually retained. If the tendons are divided as well, however, deep touch is also lost.

Care must be taken in all these injuries to prevent deformity; a splint must be worn, at least during the night, until the muscles regain their power of voluntary movement, and then exercises should be instituted.

Dislocation of the ulnar nerve at the elbow results from sudden and violent flexion of the joint, the muscular effort causing stretching or laceration of the fascia that holds the nerve in its groove; it is predisposed to if the groove is shallow as a result of imperfect development of the medial condyle of the humerus, and by cubitus valgus.

The nerve slips forward, and may be felt lying on the medial aspect of the condyle. It may retain this position, or it may slip backwards and forwards with the movements of the arm. The symptoms at the time of the displacement are some disability at the elbow, and pain and tingling along the nerve, which are exaggerated by movement and by pressure. The symptoms may subside altogether, or a neuritis may develop, with severe pain shooting up the nerve.

The dislocated nerve is easily replaced, but is difficult to retain in position. In recent cases the arm may be placed in the extended position with a pad over the condyle, care being taken to avoid pressure on the nerve. Failing relief, it is better to make a bed for the nerve by dividing the deep fascia behind the medial condyle and to stitch the edges of the fascia over the nerve. This operation has been successful in all the recorded cases.

The Sciatic Nerve.—When this nerve is compressed, as by sitting on a fence, there is tingling and powerlessness in the limb as a whole, known as "sleeping" of the limb, but these phenomena are evanescent. Injuries to the great sciatic nerve are rare except in war. Partial division is more common than complete, and it is noteworthy that the fibres destined for the peroneal nerve are more often and more severely injured than those for the tibial (internal popliteal). After complete division, all the muscles of the leg are paralysed; if the section is in the upper part of the thigh, the hamstrings are also paralysed. The limb is at first quite powerless, but the patient usually recovers sufficiently to be able to walk with a little support, and although the hamstrings are paralysed the knee can be flexed by the sartorius and gracilis. The chief feature is drop-foot. There is also loss of sensation below the knee except along the course of the long saphenous nerve on the medial side of the leg and foot. Sensibility to deep touch is only lost over a comparatively small area on the dorsum of the foot.

The Common Peroneal (external popliteal) nerve is exposed to injury where it winds round the neck of the fibula, because it is superficial and lies against the unyielding bone. It may be compressed by a tourniquet, or it may be bruised or torn in fractures of the upper end of the bone. It has been divided in accidental wounds,—by a scythe, for example,—in incising for cellulitis, and in performing subcutaneous tenotomy of the biceps tendon. Cases have been observed of paralysis of the nerve as a result of prolonged acute flexion of the knee in certain occupations.

When the nerve is divided, the most obvious result is "drop-foot"; the patient is unable to dorsiflex the foot and cannot lift his toes off the ground, so that in walking he is obliged to jerk the foot forwards and laterally. The loss of sensibility depends upon whether the nerve is divided above or below the origin of the large cutaneous branch which comes off just before it passes round the neck of the fibula. In course of time the foot becomes inverted and the toes are pointed—pes equino-varus—and trophic sores are liable to form.

The Tibial (internal popliteal) nerve is rarely injured.

The Cranial nerves are considered with affections of the head and neck (Vol. II.).

NEURALGIA

The term neuralgia is applied clinically to any pain which follows the course of a nerve, and is not referable to any discoverable cause. It should not be applied to pain which results from pressure on a nerve by a tumour, a mass of callus, an aneurysm, or by any similar gross lesion. We shall only consider here those forms of neuralgia which are amenable to surgical treatment.

Brachial Neuralgia.—The pain is definitely located in the distribution of one of the branches or nerve roots, is often intermittent, and is usually associated with tingling and disturbance of tactile sensation. The root of the neck should be examined to exclude pressure as the cause of the pain by a cervical rib, a tumour, or an aneurysm. When medical treatment fails, the nerve-trunks may be injected with saline solution or recourse may be had to operative measures, the affected cords being exposed and stretched through an incision in the posterior triangle of the neck. If this fails to give relief, the more serious operation of resecting the posterior roots of the affected nerves within the vertebral canal may be considered.

Neuralgia of the sciatic nerve—sciatica—is the most common form of neuralgia met with in surgical practice.

It is chiefly met with in adults of gouty or rheumatic tendencies who suffer from indigestion, constipation, and oxaluria—in fact, the same type of patients who are liable to lumbago, and the two affections are frequently associated. In hospital practice it is commonly met with in coal-miners and others who assume a squatting position at work. The onset of the pain may follow over-exertion and exposure to cold and wet, especially in those who do not take regular exercise. Any error of diet or indulgence in beer or wine may contribute to its development.

The essential symptom is paroxysmal or continuous pain along the course of the nerve in the buttock, thigh, or leg. It may be comparatively slight, or it may be so severe as to prevent sleep. It is aggravated by movement, so that the patient walks lame or is obliged to lie up. It is aggravated also by any movement which tends to put the nerve on the stretch, as in bending down to put on the shoes, such movements also causing tingling down the nerve, and sometimes numbness in the foot. This may be demonstrated by flexing the thigh on the abdomen, the knee being kept extended; there is no pain if the same manoeuvre is repeated with the knee flexed. The nerve is sensitive to pressure, the most tender points being its emergence from the greater sciatic foramen, the hollow between the trochanter and the ischial tuberosity, and where the common peroneal nerve winds round the neck of the fibula. The muscles of the thigh are often wasted and are liable to twitch.

The clinical features vary a good deal in different cases; the affection is often obstinate, and may last for many weeks or even months.

In the sciatica that results from neuritis and perineuritis, there is marked tenderness on pressure due to the involvement of the nerve filaments in the sheath of the nerve, and there may be patches of cutaneous anaesthesia, loss of tendon reflexes, localised wasting of muscles, and vaso-motor and trophic changes. The presence of the reaction of degeneration confirms the diagnosis of neuritis. In long-standing cases the pain and discomfort may lead to a postural scoliosis (ischias-scoliotica).

Diagnosis.—Pain referred along the course of the sciatic nerve on one side, or, as is sometimes the case, on both sides, is a symptom of tumours of the uterus, the rectum, or the pelvic bones. It may result also from the pressure of an abscess or an aneurysm either inside the pelvis or in the buttock, and is sometimes associated with disease of the spinal medulla, such as tabes. Gluteal fibrositis may be mistaken for sciatica. It is also necessary to exclude such conditions as disease in the hip or sacro-iliac joint, especially tuberculous disease and arthritis deformans, before arriving at a diagnosis of sciatica. A digital examination of the rectum or vagina is of great value in excluding intra-pelvic tumours.

Treatment is both general and local. Any constitutional tendency, such as gout or rheumatism, must be counteracted, and indigestion, oxaluria, and constipation should receive appropriate treatment. In acute cases the patient is confined to bed between blankets, the limb is wrapped in thermogene wool, and the knee is flexed over a pillow; in some cases relief is experienced from the use of a long splint, or slinging the leg in a Salter's cradle. A rubber hot-bottle may be applied over the seat of greatest pain. The bowels should be well opened by castor oil or by calomel followed by a saline. Salicylate of soda in full doses, or aspirin, usually proves effectual in relieving pain, but when this is very intense it may call for injections of heroin or morphin. Potassium iodide is of benefit in chronic cases.

Relief usually results from bathing, douching, and massage, and from repeated gentle stretching of the nerve. This may be carried out by passive movements of the limb—the hip being flexed while the knee is kept extended; and by active movements—the patient flexing the limb at the hip, the knee being maintained in the extended position. These exercises, which may be preceded by massage, are carried out night and morning, and should be practised systematically by those who are liable to sciatica.

Benefit has followed the injection into the nerve itself, or into the tissues surrounding it, of normal saline solution; from 70-100 c.c. are injected at one time. If the pain recurs, the injection may require to be repeated on many occasions at different points up and down the nerve. Needling or acupuncture consists in piercing the nerve at intervals in the buttock and thigh with long steel needles. Six or eight needles are inserted and left in position for from fifteen to thirty minutes.

In obstinate and severe cases the nerve may be forcibly stretched. This may be done bloodlessly by placing the patient on his back with the hip flexed to a right angle, and then gradually extending the knee until it is in a straight line with the thigh (Billroth). A general anaesthetic is usually required. A more effectual method is to expose the nerve through an incision at the fold of the buttock, and forcibly pull upon it. This operation is most successful when the pain is due to the nerve being involved in adhesions.

Trigeminal Neuralgia.—A severe form of epileptiform neuralgia occurs in the branches of the fifth nerve, and is one of the most painful affections to which human flesh is liable. So far as its pathology is known, it is believed to be due to degenerative changes in the semilunar (Gasserian) ganglion. It is met with in adults, is almost invariably unilateral, and develops without apparent cause. The pain, which occurs in paroxysms, is at first of moderate severity, but gradually becomes agonising. In the early stages the paroxysms occur at wide intervals, but later they recur with such frequency as to be almost continuous. They are usually excited by some trivial cause, such as moving the jaws in eating or speaking, touching the face as in washing, or exposure to a draught of cold air. Between the paroxysms the patient is free from pain, but is in constant terror of its return, and the face wears an expression of extreme suffering and anxiety. When the paroxysm is accompanied by twitching of the facial muscles, it is called spasmodic tic.

The skin of the affected area may be glazed and red, or may be pale and moist with inspissated sweat, the patient not daring to touch or wash it.

There is excessive tenderness at the points of emergence of the different branches on the face, and pressure over one or other of these points may excite a paroxysm. In typical cases the patient is unable to take any active part in life. The attempt to eat is attended with such severe pain that he avoids taking food. In some cases the suffering is so great that the patient only obtains sleep by the use of hypnotics, and he is often on the verge of suicide.

Diagnosis.—There is seldom any difficulty in recognising the disease. It is important, however, to exclude the hysterical form of neuralgia, which is characterised by its occurrence earlier in life, by the pain varying in situation, being frequently bilateral, and being more often constant than paroxysmal.

Treatment.—Before having recourse to the measures described below, it is advisable to give a thorough trial to the medical measures used in the treatment of neuralgia.

The Injection of Alcohol into the Nerve.—The alcohol acts by destroying the nerve fibres, and must be brought into direct contact with them; if the nerve has been properly struck the injection is followed by complete anaesthesia in the distribution of the nerve. The relief may last for from six months to three years; if the pain returns, the injection may be repeated. The strength of the alcohol should be 85 per cent., and the amount injected about 2 c.c.; a general, or preferably a local, anaesthetic (novocain) should be employed (Schlosser); the needle is 8 cm. long, and 0.7 mm. in diameter. The severe pain which the alcohol causes may be lessened, after the needle has penetrated to the necessary depth, by passing a few cubic centimetres of a 2 per cent. solution of novocain-suprarenin through it before the alcohol is injected. The treatment by injection of alcohol is superior to the resection of branches of the nerve, for though relapses occur after the treatment with alcohol, renewed freedom from pain may be obtained by its repetition. The ophthalmic division should not, however, be treated in this manner, for the alcohol may escape into the orbit and endanger other nerves in this region. Harris recommends the injection of alcohol into the semilunar ganglion.