Chapter 29

THE TONGUE

Surgical Anatomy--Wounds--Dental ulcer--Inflammatory affections: _Acute parenchymatous glossitis and hemi-glossitis_; _Mercurial glossitis_; _Chronic superficial glossitis_; _Leucoplakia_; _Smoker's patch_--_Tuberculous disease_; _Syphilitic affections_; _Sclerosing glossitis_; _Gummas_; _Ulcers and fissures_--Tumours: _Carcinoma_; _Sarcoma_; _Innocent tumours_; _Cysts_--Thyreo-glossal tumours and cysts--Malformations: _Absence_; _bifid tongue_; _Tongue-tie_; _Excessive length of frenum_; _Macroglossia_; _Atrophy_--Nervous affections.

#Surgical Anatomy.#--The tongue is composed of interlaced, striped muscle fibres, partly consisting of the terminations of the extrinsic muscles, and partly of the intrinsic muscles. A median fibrous septum divides it into two lateral halves so completely that but little communication takes place between the blood vessels and lymphatics of the two sides. It is covered by stratified squamous epithelium. For practical purposes it is described as consisting of an _anterior_ or _oral_ part, and a _posterior_ or _pharyngeal_ part.

The _oral part_, which includes the anterior two-thirds of the organ, is mobile, and the epithelium on its dorsal aspect is modified so as to form several varieties of papillae. A slight median depression is recognisable on the dorsum as far back as the vallate (circumvallate) papillae, which mark the boundary between the oral and pharyngeal parts. A double fold of mucous membrane--the _frenum_--connects the under aspect of the tip with the floor of the mouth and the mandible. On each side of the frenum, under the mucous membrane of the tip, are mucous glands--_apical glands_--in which cysts sometimes form. On the lateral border of the tongue, just in front of the anterior palatine arch, are several vertical folds of mucous membrane--the _folia linguae_, or _foliate papillae_.

The _pharyngeal_ part, or base of the tongue, forms the anterior wall of the pharynx, and is attached to the hyoid bone. Its mucous membrane is devoid of papillae, but contains numerous lymphoid follicles--the _lingual tonsil_. The _foramen caecum_ lies just behind the apex of the vallate papillae in the middle line.

The chief artery, the _lingual_, a branch of the external carotid, passes forward beneath the hyoglossus muscle, and is continued to the apex as the ranine, lying nearer the under than the upper aspect of the tongue. The pharyngeal part is supplied by the dorsalis linguae branch. The blood is returned to the internal jugular by the ranine vein, which can be seen under the mucous membrane on the inferior aspect near the frenum, and by the venae comites of the lingual artery and its branches.

The _hypoglossal_ is the motor nerve of the tongue. The _lingual_ branch of the mandibular (inferior maxillary) supplies the anterior two-thirds with common sensation. It is accompanied by the _chorda tympani_ branch of the facial, which probably carries the taste fibres. The _glosso-pharyngeal_ supplies the posterior third of the tongue with both common and gustatory sensation.

The _lymph vessels_ of the anterior two-thirds of the tongue drain into the submental and submaxillary glands, and these in turn into the deep cervical group which accompany the internal jugular vein. The vessels of the base converge into several large trunks which pass out behind the tonsils and drain directly into the deep cervical glands. One of these, which lies in the angle between the internal jugular and common facial veins, is frequently infected in cancer of the tongue.

#Wounds# are commonly produced by the teeth, as, for instance, when a child falls on the chin with the tongue protruded, or when an epileptic bites his tongue during a fit. Less frequently a foreign body, such as a pipe-stem, a bullet, or a displaced tooth, is driven into the tongue. The immediate risk is haemorrhage, particularly when the posterior part of the tongue is implicated and the wound penetrates deeply. Of the later complications, infections and secondary haemorrhage are the most serious, and they are most liable to occur when a foreign body is embedded in the tongue.

_Treatment._--In superficial wounds near the tip the oozing is efficiently arrested by sutures, but in deeper wounds a ligature must be applied to the bleeding vessel. Secondary haemorrhage is much more difficult to arrest on account of the friable state of the tissues, and it may be necessary to ligate the lingual or even the external carotid in the neck.

To prevent infective complications any foreign body must be removed and an antiseptic mouth-wash regularly employed.

Cases have been recorded in which such a foreign body as a bullet, a needle, or a piece of a pipe-stem, has remained embedded in the substance of the tongue for a long period, and caused a firm, indolent swelling liable to be mistaken for a new growth.

#Dental Ulcer.#--The continuous friction of a jagged tooth, or of an ill-fitting dental plate, is liable to cause swelling and excoriation of the side of the tongue. A painful superficial ulcer forms, and if the irritation continues and infection occurs, the surrounding parts become indurated, the ulcer assumes a crater-like appearance, not unlike that of a commencing epithelioma. If such an ulcer does not promptly heal on the removal of the irritant, a portion of the margin should be removed and submitted to microscopic examination to make sure that it is not cancerous.

#Inflammatory Affections.#--_Acute Parenchymatous Glossitis_ is usually due to the action of streptococci. Although it affects mainly the mucous membrane and submucous tissue, it causes a diffuse oedematous swelling of the whole organ, and this may extend to the ary-epiglottic folds and give rise to oedema of the glottis. As a rule it does not go on to suppuration.

The onset is sudden, and is marked by pain and stiffness of the tongue, particularly when the patient attempts to masticate or to speak. The tongue rapidly swells, and in the course of twenty-four or forty-eight hours may fill the mouth and protrude beyond the teeth. There is profuse salivation, and in addition to difficulty in swallowing and speaking there may be considerable interference with respiration. The salivary and lymph glands in the submaxillary space are enlarged and tender. The symptoms begin to subside in three or four days, unless suppuration occurs.

The _treatment_ consists in administering a sharp purge and employing a mouth-wash; leeches may be applied to the submaxillary region with benefit. When the swelling is excessive, it may be necessary to make longitudinal incisions into the substance of the tongue, and dyspnoea may call for laryngotomy. If an abscess forms it must be opened.

A similar condition has been met with in patients who have contracted the "_foot and mouth disease_" of cattle. Vesicles form on the mucous membrane, and after bursting, ulcerate, and a mixed infection with streptococci occurs, leading to diffuse oedema. Portions of the tongue may become gangrenous, and the infection may spread to the tissues of the neck and set up one form of angina Ludovici. The condition is usually fatal.

_Acute Hemi-glossitis._--An acute transitory swelling, confined to one half of the tongue, in the distribution of the lingual nerve, is occasionally met with. It is attended with great pain and high temperature, and is believed to be analogous to herpes zoster (Gueterbock).

_Mercurial Glossitis_ may accompany mercurial stomatitis (p. 496).

_Chronic Superficial Glossitis._--Several forms of chronic superficial glossitis are met with. The most important, as it is frequently followed by the development of epithelioma, is that known as _leucoplakia_ or _leucokeratosis_.

The tongue is studded over with white patches, which result from overgrowth and cornification of the surface epithelium, whereby it becomes thickened and raised above the surface, and at the same time there is small-celled infiltration of the submucous tissue. The patches are irregularly lozenge-shaped, and when crowded together they present the appearance of a mosaic (Fig. 257). Similar patches are often present on the mucous membrane lining the cheek.

The disease is met with almost invariably in men between the ages of forty and fifty. Syphilis appears to be a predisposing factor, and any form of irritation--for example, the chewing or smoking of tobacco, the drinking of raw spirits, friction by a rough tooth or tooth-plate--plays an important part in inducing or in aggravating the condition.

The milder forms give rise to no discomfort, but when the condition is advanced the patient complains of dryness and hardness of the tongue, with impairment of the sense of taste and persistent thirst. When cracks, fissures, or warts develop, there is pain on chewing or speaking, or on taking hot or irritating food. The glands below the jaw may be enlarged.

The disease is most intractable and persistent, and even after disappearing for a time is liable to recur. After a variable number of years epithelioma is prone to develop, usually in one or other of the fissures which accompany the condition.

The _treatment_ consists in removing all sources of irritation, particularly smoking, and in employing mouth-washes. Butlin recommends antiseptic ointments applied before going to bed. In some cases painting the patches with chromic acid (10 grains to the ounce) or lactic acid (20 per cent.) is useful in removing the excess of epithelium, but stronger caustics are to be avoided. Constitutional treatment is of little use even when the patient has suffered from syphilis. The best results have been attained by the use of radium.

The "_smoker's patch_" consists of a small oval area on the front of the tongue from which the papillae have disappeared. It is slightly raised, smooth and red, and may be covered with a yellowish-brown or yellowish-white crust. It causes no discomfort unless the crust is removed, when a raw, sensitive surface is exposed. The condition is liable to spread over the tongue if the patient persists in smoking. It may eventually assume the characters of leucoplakia. The _treatment_ consists in stopping the use of tobacco, and painting the patches with chromic acid, tannic acid, or alum, and employing a chlorate of potash mouth-wash.

#Tuberculous Disease.#--The tongue is rarely the primary seat of tuberculosis. The majority of cases occur in adult males, who suffer from advanced pulmonary or laryngeal phthisis, the tongue being infected by bacilli from the sputum or through the blood stream. In other cases the infection is due to direct spread of lupus from the face or nose.

The condition may begin as a firm, painless lump, seldom larger than a hazel-nut, on one side of the tongue, or near its tip. At first the swelling is covered by epithelium; in time caseation takes place, the epithelium gives way, and an open sore is formed.

The _tuberculous ulcer_ is the form most frequently met with. The surface of the ulcer is uneven, pale and flabby, and is covered with a yellowish-grey discharge, with here and there feeble granulations showing through. The edges are shreddy, sinuous in outline, and there is little or no induration. The surrounding parts are slightly swollen, and may be studded with small tuberculous foci. The ulcer may be quite superficial, or it may extend into the muscular substance, and the tip of the tongue may be completely eaten away so that it looks as if it had been cut off with a knife. As the disease advances there is severe pain and usually profuse salivation. The submaxillary glands may be, but are not always, enlarged. The ulcer may heal, but tends to break down again.

Unless there is advanced pulmonary disease or other contraindication to operation, the ulcer should be excised under local anaesthesia. Care must be taken to avoid reinfecting the raw surface. When excision is impracticable, it is only possible to palliate the symptoms by dusting with orthoform, or applying local anaesthetics, and by attending to the hygiene of the mouth and removing all sources of irritation.

#Syphilitic Affections.#--A _primary lesion_ on the tongue is accompanied by marked enlargement and tenderness of the submaxillary lymph glands on one or on both sides. It is most common in men, infection usually taking place through the medium of tobacco pipes, or implements such as the blow-pipes of glass-blowers.

During the _secondary stage_--particularly in the later periods--mucous patches and ulcers are common, and they may assume a condylomatous or warty appearance.

The _tertiary_ manifestations in the tongue are sclerosing glossitis, gummas, and gummatous ulcers.

_Sclerosing glossitis_ is the term applied by Fournier to a condition in which there is an abundant new formation of granulation tissue in the substance of the tongue, leading to the appearance of tuberous masses on the dorsum. These tend to be oval in outline, are elevated above the normal mucous membrane, and present a dull red mammilated or lobulated surface, comparable to the surface of a cirrhotic liver. They are firm, elastic, and insensitive.

A _gumma_ is usually situated on the dorsum and more often towards the centre than at the edges. As it seldom implicates the floor of the mouth or the base of the tongue, the tongue can usually be protruded freely. It forms an indolent swelling, which tends to break down slowly and to ulcerate. So long as it remains unbroken it does not cause pain, and there is no enlargement of the adjacent lymph glands. Two forms are met with--the superficial, and the deep or parenchymatous.

A _superficial_ gumma appears as a small hard nodule under the mucous membrane, varying in size from a pin's head to a pea. The mucous membrane over it is redder than normal, and in the early stages retains its papillae but later becomes smooth. It tends to break down early, forming a superficial ulcer. Superficial gummas are often multiple.

The _deep_ or parenchymatous form varies in size from a hazel-nut to a walnut, and feels like a hard body in the substance of the tongue. The mucous membrane over the swelling is of normal colour, but is usually devoid of papillae. The gumma may remain for months unchanged, or may approach the surface, soften, and break down, leaving a deep, ragged ulcer.

_Syphilitic ulcers and fissures_ are nearly always due to the softening and breaking down of gummas. The ulcers have seldom the typically rounded or serpiginous outline of gummatous ulcers on other parts of the body. The base is ragged and unhealthy, and on it a yellowish-grey slough resembling wash-leather may be seen. The edges are steep, ragged, and often undermined, and the surrounding parts thickened and indurated. The neighbouring glands are not usually enlarged. The ulcer is extremely painful when irritated by food, hot fluids, or spirits. If untreated, the sore may remain indolent and for months show no sign either of spreading or healing, but at any time it may become the seat of cancer.

Syphilitic fissures are met with as long, narrow, deep clefts, or as stellate or sinous cracks in the substance of the tongue. After the healing of these ulcers and fissures permanent furrows and depressed scars remain.

_Treatment._--The tertiary manifestations of syphilis in the tongue are treated on the same lines as other tertiary lesions. Locally, the use of mouth-washes, such as chlorate of potash or black wash diluted with lime-water, the insufflation of powdered iodoform and borax with a small quantity of morphin, or the application of mercurial ointment is useful. The sore must be thoroughly cleansed before these remedies are applied.

NEW GROWTHS

#Carcinoma# is by far the most common form of new growth met with in the tongue, and it is almost invariably a squamous epithelioma.

Epithelioma generally occurs between the ages of forty and sixty, and attacks males oftener than females, in the proportion of about six to one. Its development is favoured by any long-continued irritation, such as the rubbing of the tongue against a carious tooth, an ill-fitting tooth-plate, or the rough end of a short clay pipe, particularly when such irritation leads to the formation of an ulcer. Chronic superficial glossitis associated with leucoplakia, and syphilitic fissures, ulcers, or scars, also act as predisposing factors. The repeated application of strong caustics to chronic inflammatory conditions is, according to Butlin, a determining cause of cancer. The degree of malignancy appears to vary in different cases, and is probably lowest when the disease originates in a patch of leucoplakia or other pre-cancerous lesion.

The disease is usually situated in the anterior half of the tongue, and more commonly on the edge than on the dorsum. It may begin as an excoriation, ulcer, or fissure, or as a warty growth, particularly in association with a patch of leucoplakia. In all cases ulceration begins early, and the base of the ulcer and the surrounding parts become indurated. The lymph glands are, as a rule, early infected.

_Clinical Features._--The clinical appearances vary widely. Sometimes the surface presents a warty growth; sometimes it is excavated, forming a deep ulcer with raised nodular edges; in other cases the ulcer is smooth, and its edges even and rounded. Extreme hardness of the edges and base of the ulcer is always a characteristic feature. The tongue tends to become fixed, especially when the disease spreads to the floor of the mouth, so that it cannot be protruded, and the restriction of its movement produces a characteristic interference with articulation, certain words being slurred, and when the fixation is extreme it may interfere with mastication and swallowing. The patient complains of a constant gnawing pain in the tongue, and of severe pain shooting along the branches of the trigeminal nerve, and especially towards the ear. In the advanced stages there is salivation and foetor of the breath.

When the disease is situated on the edge of the tongue it tends to spread to the floor of the mouth and the muco-periosteum of the mandible. If situated far back on the dorsum, it spreads on to the epiglottis, the pillars of the fauces, and the tonsil.

The neighbouring lymph glands--particularly those under the jaw and along the line of the carotid vessels--soon become infected and are palpable. The submaxillary and sublingual salivary glands are also liable to be affected. The enlarged cervical glands later undergo softening, or suppurate and burst on the skin surface, forming fungating ulcers. Metastasis to the liver, lungs, and other viscera is exceptional. If the disease is allowed to run its course, the patient usually dies in from twelve to eighteen months from repeated small haemorrhages, toxin absorption, or septic broncho-pneumonia.

_Differential Diagnosis._--Cancer of the tongue has to be diagnosed from syphilitic and tuberculous affections, from papilloma, and from simple ulcer and fissure. It is to be borne in mind that any of these conditions may take on malignant characters and develop into epithelioma. The microscopic examination of a portion of the growth removed under local anaesthesia from the base of the ulcer at some distance from its epithelial core is often the only certain means of establishing the diagnosis, and should be had recourse to as early as possible. When there is still doubt as to the nature of the growth, it should be treated as if it were cancerous.

An unbroken gumma is liable to be confused only with the uncommon form of epithelioma which begins as a nodule under the mucous membrane. Gumma, however, are often multiple, and the tongue shows old scars or other evidence of syphilis.

Gummatous ulcers are usually situated on the dorsum, are frequently multiple, and have sloughy, undermined edges; the surrounding parts, although indurated, are not so densely hard as in cancer; there is not necessarily any involvement of lymph glands. The cancerous ulcer is usually single and situated on the margin of the tongue; its edges are hard, raised, and nodular; and the glands are usually enlarged and hard. Little reliance is to be placed on the therapeutic effects of anti-syphilitic drugs in the differential diagnosis, as they are often inconclusive, and their use results in loss of time.

Tuberculous ulcers usually occur in association with other and unmistakable evidences of tuberculosis. A papilloma, when sessile, may simulate cancer; these tumours show a marked tendency to become malignant. Simple ulcers and fissures are usually recognised by the history of the condition, the absence of induration and of glandular involvement, and by the fact that they heal quickly on removal of the cause.

_Treatment._--The only treatment that offers any hope of cure is free removal of the disease, and experience has proved that unless this is done early the prospect of the cure being a radical one is remote. Not only must the segment of the tongue on which the growth is situated be widely excised, but all the lymphatic connections must also be removed whether the glands are palpably enlarged or not.

The chief risk after operation is pneumonia resulting from the inhaling of blood and products of infection: hence the importance of rendering the mouth as dry and as sweet as possible before operation, special attention being paid to the teeth, and precautions being taken at the operation to prevent the passage of blood down the trachea. The patient is usually able to be out of bed on the second or third day, and is well in a fortnight or three weeks. The operation, even when followed by recurrence, usually prolongs life by six or eight months, and renders the patient more comfortable by removing the foul ulcer from the mouth. The speech, although impaired by the removal of one-half or even more of the tongue, is distinct enough for ordinary purposes. When recurrence takes place it is usually in the glands, and may be attended with great suffering.

_Treatment of Inoperable Cases._--The mouth must be kept as sweet as possible. The pain may be relieved to some extent by cocain or orthoform, but as a rule the free administration of morphin is called for. Pain shooting up to the ear may be relieved by resection of the lingual nerve, or the injection of alcohol into its substance. If haemorrhage takes place from the ulcerated surface and cannot be controlled by adrenalin, or other local styptics, it may be necessary to ligate the lingual, or even the external carotid artery. Interference with respiration may necessitate tracheotomy. When the patient has difficulty in taking food, recourse should be had to the use of the stomach-tube or to gastrostomy. The use of radium or of the X-rays appears to have a restraining influence on the disease in the glands, but has not proved curative.

#Sarcoma# of the tongue is rare, and is sometimes met with in children. The round-cell type is the most common; it grows rapidly, and tends to ulcerate and fungate, pain becoming severe when the growth has broken down. The diagnosis is always difficult, and is seldom made until a portion of the growth has been removed and examined microscopically. The more slowly growing forms, if removed before ulceration has taken place, show little tendency to recur, but those which grow rapidly and break down, not only recur locally, but are liable to give rise to metastases. The treatment is the same as for cancer; the use of radium is more likely to be beneficial than in epithelioma.

#Innocent Tumour and Cysts.#--_Lipoma_, _fibroma_, and various forms of _angioma_ (Fig. 258) are occasionally met with. They are all of slow growth, and give rise to inconvenience chiefly by their bulk, and should be removed.

_Papilloma_ may occur on any part of the tongue, and at any age. It may be single or multiple, pedunculated or sessile, and is liable to become malignant, especially when associated with leucoplakia. It should be freely removed by excising a wedge-shaped portion of the tongue.

_Dermoid_ cyst is met with beneath the tongue, lying in the middle line, between the genio-glossi (genio-hyoglossi), and on the upper surface of the mylo-hyoid muscles. It may be noticed soon after birth, or may only attract attention during adult life. The cyst usually projects under the chin, forming a soft swelling of putty-like consistence, which varies in size from a pigeon's to a turkey's egg (Fig. 259). When it bulges towards the mouth it is liable to be mistaken for a retention cyst of one of the salivary glands. It is distinguished by its medial position, its yellow colour, and its opacity, the retention cyst being to one side of the middle line, purplish in colour, translucent and fluctuating. The cyst should be dissected out, either from the mouth or from under the chin, according to circumstances.

A _sebaceous cyst_ may reach such dimensions as to simulate a dermoid or thyreo-glossal cyst.

_Hydatid and cysticercus cysts_ have also been met with in the tongue.

#Thyreo-glossal Tumours and Cysts.#--Tumours may develop in the embryonic tract which passes from the isthmus of the thyreoid gland to the foramen caecum at the base of the tongue--the thyreo-glossal tract of His. They have the same structure as the thyreoid gland, and occupy the dorsum of the tongue, extending from the foramen caecum backwards towards the epiglottis, in some cases attaining considerable size. They are of a bluish-brown or dark red colour, and are liable to repeated attacks of haemorrhage. These tumours sometimes become cystic, the cysts being lined with ciliated epithelium and containing colloid material. Bleeding may take place into a cyst, causing it to become suddenly enlarged, or the cyst may burst and the blood escape into the mouth. These variations in size and repeated attacks of bleeding help to distinguish thyreo-glossal cysts from other swellings of the tongue. Treatment is only called for when the swelling causes interference with speech or swallowing; it consists in removing the tumour by dissection.

When the lower end of the tract becomes cystic it forms a swelling in the neck (p. 583).

#Malformations.#--Complete or partial _absence_ of the tongue is exceedingly rare.

Occasionally the fore part of the tongue is _bifid_. The function of the organ is not interfered with, and the operation of paring and suturing the two halves is only called for on account of the disfigurement.

_Congenital tongue-tie_ is a condition in which the tip of the tongue is bound down to the floor of the mouth by an abnormally short and narrow frenum, or by folds of mucous membrane on each side of the frenum, so that the tongue cannot be protruded. Although this deformity is rare, it is common for parents to blame an imaginary tongue-tie when a child is slow in learning to speak, or when he speaks indistinctly or stammers, and the doctor is frequently requested to divide the frenum under such circumstances. In the vast majority of cases nothing is found to be wrong with the frenum. In the rare cases of true tongue-tie the edges of the shortened bands should be snipped with scissors close behind the incisor teeth, and then torn with the finger-nail.

_Excessive length_ of the frenum is occasionally met with, and in children may allow of the tongue falling back into the throat and causing sudden suffocative attacks, one of which may prove fatal. In some cases the patient is able voluntarily to fold the tongue back behind the soft palate.

_Macroglossia_ is the term applied to a variety of conditions in which the tongue becomes unduly large, so that it tends to be protruded from the mouth, and to become scored by the teeth. The typical form--lymphangiomatous macroglossia--is due to a dilatation of the lymph spaces of the tongue. It is often congenital, and may affect the whole or only a part of the tongue. The enlargement may be progressive from the first, or may remain stationary for years, and then begin to develop somewhat suddenly, sometimes after an injury or as a result of some infective condition. The treatment consists in removing a wedge-shaped portion of the tongue.

In certain cases of macroglossia in children, the lesion has been found to be a fibromatosis of the nerves of the tongue, analogous to the plexiform neuroma.

_Atrophy_ of the tongue is rare as a congenital condition. Hemi-atrophy occurs in various diseases of the central nervous system, as well as after injuries and diseases implicating the hypoglossal nerve.

#Nervous Affections of the Tongue.#--_Neuralgia_ confined to the distribution of the lingual nerve is comparatively rare. It usually yields to medical treatment, but in inveterate cases it is sometimes necessary to resect the nerve.

It is more common to meet with a condition in which the patient complains of severe burning or aching pain in the region of the foliate papilla, which is situated on the edge of the tongue just in front of the anterior pillar of the fauces. The patient is usually a middle-aged, neurotic woman, and often with a gouty or rheumatic tendency. The pain, for which it is seldom possible to discover any cause, is usually worst at night, and may last for months, or even years. The practical importance of the condition is that, as the foliate papilla is prominent and red, it is liable to be mistaken on superficial examination for a commencing epithelioma. An inspection of the opposite side of the tongue, however, will reveal an exactly similar condition, which is not painful. The first and most important step in treatment is to assure the patient that the condition is not cancerous. Caustics and other irritating applications are to be avoided.

_Spasm_ of the tongue sometimes occurs after injuries of the head implicating either the centre or the trunk of the hypoglossal nerve. It may also appear as a reflex condition in infective affections of the teeth and gums, or as a manifestation of some general disease of the central nervous system.

_Paralysis_ of the tongue--unilateral or bilateral--may be due to injury or disease of the nerve centres of the hypoglossal nerve, more frequently to injury of or pressure on the nerve-trunk. The nerve may be bruised or divided in operations for the removal of tuberculous glands or other tumours in the neck. When the tongue is protruded it deviates towards the paralysed side, being pushed over by the active muscles of the opposite side (Fig. 260), and speech and mastication may be interfered with. The paralysed half of the tongue subsequently undergoes atrophy, but the functional disability largely disappears.