In the presence of an open wound, the venous source of the bleeding is recognised by the dark colour of the blood and the continuous character of the stream. It may be arrested by pressure with gauze pads or by packing a strand of catgut into the sinus (Lister), or, if this fails, by grasping the sinus with forceps and leaving these in position for twenty-four or forty-eight hours. A small puncture in the outer wall of the sinus may be closed with sutures. Signs of increasing compression call for trephining and opening of the dura if this is necessary to admit of the clot being removed.

Intra-cranial Haemorrhage in the Newly-Born.—An extravasation of blood into the arachno-pial space frequently occurs during birth. The observations of Cushing seem to show that this is usually due to tearing of the delicate cerebral veins which pass from the cortex to the superior sagittal sinus, from the strain put upon them by the overlapping of the parietal bones, in the moulding of the head. It may sometimes be due to an excessive degree of asphyxia during birth. The extravasation is usually most marked over the central area of the cortex near the middle line, and it is often bilateral.

This condition is most frequently met with in a first-born child—and more often in boys than in girls—the labour having been prolonged and difficult, and the presentation abnormal. There is usually a history that the infant was deeply cyanosed when born, and that there was difficulty in getting it to breathe. As a rule, there is no external evidence of trauma. The anterior fontanelle is tense and does not pulsate, the pulse is slow, and for several days the child appears to have difficulty in sucking and swallowing, and is abnormally still. In the course of a few days definite symptoms of localised pressure appear. It is noticed that one leg or arm, or one side of the body is not moved, or both sides may be affected; when the paralysis is bilateral, the absence of movement is more liable to be overlooked. The infant may suffer from convulsions; there may be paralysis of certain of the ocular muscles, and inequality of the pupils; sometimes there is blindness. Persistent rigidity of the limbs, with turning of the thumbs towards the palm, is present in some cases. Lumbar puncture may reveal the presence of blood corpuscles in the cerebro-spinal fluid, and increase in the tension of the fluid.

If untreated, the condition is usually followed by the development of spastic paralysis of one or more limbs, on one or on both sides of the body (Little's disease), by blindness, deafness, and varying degrees of mental deficiency, or by Jacksonian epilepsy.

Treatment.—To obviate these after-effects the clot may be removed by raising an osteo-plastic flap, including nearly the whole of the parietal bone. The operation should be undertaken within the first week or two, and great care must be taken to keep up the body-warmth, and to prevent undue loss of blood. It may be necessary to operate on both sides, an interval being allowed to elapse between the two operations.

For the immediate relief of increased intra-cranial tension, the daily withdrawal of 10-12 c.c. of cerebro-spinal fluid by lumbar punctures may be employed, or a sub-temporal decompression operation may be performed.

WOUNDS OF THE BRAIN

Wounds of the Brain.—Incised wounds of the brain usually result from sabre-cuts, hatchet blows, or circular saws. A portion of the scalp and cranium may be raised along with a slice of brain matter, and in some cases the whole flap is severed. The extent of the injury, the conditions under which it is received, and the liability to infection, render such wounds extremely dangerous.

Punctured wounds may be inflicted on the vault by stabs with a knife or dagger, or by other sharp objects, such as the spike of a railing. More frequently a pointed instrument, such as a fencing foil, the end of an umbrella, or a knitting needle, is thrust through the orbit into the base of the brain. Occasionally the base of the skull has been perforated through the roof of the pharynx, for example, by the stem of a tobacco-pipe. All such wounds are of necessity compound, and the risk of infection is considerable, particularly if the penetrating object is broken and a portion remains embedded within the skull. The infective complications of such injuries are described later.

Bullet wounds have many features in common with punctured wounds. There is more contusion of the brain substance, disintegrated brain matter is usually found in the wound of entrance, and the bullet often carries in with it pieces of bone, cloth, or wad, thus adding to the risk of infection.

Aseptic foreign bodies, especially bullets, may remain embedded in the brain without producing symptoms.

The treatment of punctured wounds consists in enlarging the wounds in the soft parts, trephining the skull, and removing any foreign body that may be in it, purifying the track, and establishing drainage.

AFTER-EFFECTS OF HEAD INJURIES

Various after-effects may follow injuries of the head. Thus, for example, chronic interstitial changes (sclerosis) may spread from an area of cicatrisation in the brain; or softening may ensue, either in the form of pale areas of necrosis (white softening) or of haemorrhagic patches (red softening). The symptoms vary with the area implicated. Adhesions between the brain and its membranes may produce severe headache and attacks of vertigo, especially on the patient making sudden exertion.

After a head injury, the patient's whole mental attitude is sometimes changed, so that he becomes irritable, unstable, and incapacitated for brain-work—traumatic neurasthenia. In some cases self-control is lost, and alcoholic and drug habits are developed.

Traumatic epilepsy may ensue as a result of some circumscribed cortical lesion, such as a spicule of bone projecting into the cortex, the presence of adhesions between the membranes and the brain, a cicatrix in the brain tissue leading to sclerosis or a haemorrhagic cyst in the membranes or cerebral tissue.

The convulsive attacks are of the Jacksonian type, beginning in one particular group of muscles and spreading to neighbouring groups till all the muscles of the body may be affected. The convulsions may begin soon after the injury, for example, when the cause is a fragment of bone irritating the cortex; in other cases it may be several years before they make their appearance. The onset is usually sudden, and the "signal symptom"—for example, jerking of the thumb, conjugate deviation of the eyes, or motor aphasia—indicates the seat of the lesion. At first the attacks only recur at intervals of, it may be weeks or months, but as time goes on they become more and more frequent, until there may be as many as forty or fifty in a day. Sometimes the patient loses consciousness during the fit; sometimes he remains partly conscious. In course of time the same degenerative changes as occur in other forms of epilepsy ensue: certain groups of muscles may become paralysed; the patient may pass into a state of idiocy, or into what is known as the "status epilepticus," in which the fits succeed one another without remission, the breathing becomes stertorous, the temperature rising, the pulse becoming very rapid; finally coma supervenes, and the patient dies.

Treatment.—The administration of bromides is only palliative. Operation is indicated only when the "signal symptom" indicates a limited and accessible portion of the brain as the seat of the lesion, or when there is a depression of the skull or other definite evidence of cranial injury. The more recent the injury the better is the prospect, as secondary changes are less likely to have taken place, and the peculiarly irritable state of the brain—sometimes referred to as the "epileptic habit"—has not developed. The operation consists in opening the skull freely, and removing any discoverable cause of irritation—depressed bone, thickened and adherent membranes, a cyst, or sclerosed patch of cortex; it may be necessary to interpose a layer of tissue, a flap of fascia lata, for example, between the bone and the cortex of the brain. The point at which the skull is opened is determined by the seat of the injury and the focal brain symptoms.

The return of fits within a few days of the operation does not necessarily mean failure, as they often pass off again. Complete and permanent cure is not common, but the number and severity of the attacks are usually so far diminished that life is rendered bearable.

Traumatic insanity may follow injury to any part of the brain, and it may come on either immediately or after an interval. It may or may not be associated with epilepsy. Any form of insanity may occur, either as a direct result of the trauma, or from the resistance of the brain being lowered by the injury in a patient predisposed to insanity. When insanity follows as a direct consequence of injury, the organic lesion is usually a superficial one, and the disturbance of brain function is generally due to reflex irritation of the dura mater (Duret). These facts possibly explain the immediate improvement which occasionally follows the opening of the skull at the point of injury and removal of the exciting cause. Cases occurring within a few days of the injury usually recover within a month or two. The later the condition is in developing the less obvious is the relationship between the trauma and the insanity, and therefore the worse is the prognosis.

Meningitis, sinus thrombosis, and cerebral abscess may follow upon any form of head injury attended with infection. The clinical features—save for the history of a trauma—correspond so closely with those of the same conditions occurring apart from injury, that they are most conveniently considered together (p. 374).



CHAPTER XIII

INJURIES OF THE SKULL

Contusions—FRACTURES—Of the vault: Varieties—Of the Base: Anterior fossa—Middle fossa—Posterior fossa.

The bones of the skull may be contused or fractured. These injuries are not in themselves serious: their clinical importance is derived from the injury to the intra-cranial contents with which they are liable to be associated.

Contusion of the skull may result from a fall, a blow, or a gun-shot injury. In the majority of cases the damage to soft parts—scalp, meningeal vessels, or brain—overshadows the osseous lesion, which of itself is comparatively unimportant.

FRACTURES OF THE SKULL

While it is convenient to consider separately fractures of the vault and fractures of the base of the skull, it is to be borne in mind that it is not uncommon for a fracture to involve both the vault and the base. Fractures in either situation may be simple or compound.

FRACTURES OF THE VAULT

Mechanism.—When the skull is broken by direct violence, the fracture takes place at the seat of impact, and its extent varies with the nature of the impinging object and the degree of violence exerted. If, for example, a pointed instrument, such as a bayonet, a foil, or a spike, is forcibly driven against the skull, the weapon simply crashes through the bone, disintegrating it at the point of entrance, and cracking or splintering it for a variable, but limited, distance beyond. On the other hand, when the head is struck by a "blunt" object—for example, a batten falling from a height—the force is applied over a wider area and the elastic skull bends before it. If the limits of its elasticity are not exceeded, the bone recoils into its normal position when the force ceases to act; but if the bone is bent beyond the point from which it can recoil, a fracture takes place—"fracture by bending." The bone gives way over a wide area, the affected portion may be comminuted, and one or more of the fragments may remain depressed below the level of the rest of the skull. Cracks and fissures spread widely in different directions—often (70 to 75 per cent.) extending into the base. In almost all fractures of the vault the inner table splinters over a wider area than the outer, partly because it is more brittle and is not supported from within, but also because the diffusion of the force as it passes inwards affects a wider area. If a bullet traverses the cranial cavity the inner table is more widely shattered at the aperture of entrance, and the outer table at the aperture of exit. Von Bergmann reported thirty cases in which the inner table alone was fractured by a blow on the head.

Fractures by indirect violence—that is, fractures in which the bone breaks at a point other than the seat of impact—are almost always due to violence inflicted with a blunt object, and acting over a wide area—such, for example, as when the head strikes the pavement. Much discussion has taken place as to the method of their production. It has been shown that when the skull is depressed at one point by a force impinging on it, it bulges at another, so that its whole contour is altered. But the elasticity of the bone varies at different parts of the skull, owing to differences in thickness and in structure. If, therefore, the part which is depressed—that is, the part directly struck—happens to be less elastic than the part which bulges, it gives way, and a fracture by "bending" results; but if the bulging part is the less elastic, it bursts outwards—fracture by "bursting." The term "fracture by contre-coup" has been incorrectly applied to such fractures when the area of bulging happens to be opposite to the seat of impact. Contre-coup, properly so-called, is only possible in a perfectly spherical body, which, of course, the skull is not.

When a high-velocity bullet penetrates the head, it exerts on the incompressible, semi-fluid brain an explosive (hydro-dynamic) force, which is transmitted to all points on the inner surface of the skull and leads to shattering of the bone.

Repair.—The repair of fractures of the skull is usually attended with an exceedingly small amount of callus. Except in the presence of infection, separated fragments live and become reunited, but they may unite in such a manner as to project towards the brain and, by irritating the cortical centres, cause traumatic epilepsy. In comminuted fractures, the lines of fracture remain permanently visible on the bone, but fissured fractures may leave no trace. Gaps left in the skull by injury or operation are, after a time, filled in by a fibrous membrane, which may undergo ossification from the periphery towards the centre, but unless the aperture is a small one it is seldom completely closed by bone. The new bone which forms is derived from the old bone at the margins of the opening. Permanent defects in the skull are chiefly injurious if they are accompanied by lesions of the underlying dura, such as adhesions to the brain; large gaps may cause giddiness on stooping, or on forcible expiration, as in blowing the nose or playing a wind instrument.

Varieties.—For descriptive purposes, fractures of the vault are divided into the fissured, the punctured, the depressed, and the comminuted varieties. Clinically, however, these varieties are often combined. The practical importance of a given fracture depends upon whether it is simple or compound, rather than upon the exact nature of the damage done to the bone. Compound fractures which open the dura mater are the most serious. Simple fractures result, as a rule, from diffuse forms of violence, and are liable to spread far beyond the seat of impact. Compound fractures result from severe and localised violence—for example, the kick of a horse or the blow of a hammer—and tend to be limited more or less to the seat of impact. In gun-shot injuries, however, there are usually numerous fissures radiating from the point at which the missile enters the skull.

Fissured fractures generally result from blows by blunt objects or from falls, and they usually extend far beyond the area struck, in most cases passing into the base. The fissure may pass through the bone vertically or obliquely, and it may implicate one or both tables. So long as the fracture is simple, it can scarcely be diagnosed except by inference from the associated symptoms of meningeal or cerebral injury. When compound, the crack in the bone can be seen and felt. It is recognised by the eye as a split in the bone, filled with red blood, which, as often as it is sponged away, oozes again into the gap. In fractures by bursting a tuft of hair may be caught between the edges of the fracture, and this adds to the difficulty of purifying the wound.

Diagnosis.—A normal suture may be mistaken for a fissured fracture. A suture, however, may generally be recognised by its position, the irregularity of its margins, and the absence of blood between its edges. At the same time, it is not uncommon, especially in children, for a suture to be sprung by violence applied to the head, or for a fissured fracture to enter a suture and, after running in it for some distance, to leave it again. The edges of a clean cut in the periosteum may be mistaken for a fissure in the bone, especially if reliance is placed on the probe for diagnosis. This error can be avoided by raising the edge of the periosteum from the bone, with the gloved finger. On combined auscultation and percussion a peculiar "hollow-cask" sound may be detected in some cases of fissured fracture of the vault.

Fissured fractures as such call for no treatment. When compound, the wound must be disinfected; and intra-cranial complications, such as meningeal haemorrhage, laceration of the brain, or infection, are to be treated on the lines already described.

Punctured fractures are of necessity compound, and on account of the risks of infection are to be looked upon as serious injuries. They result from the localised impact of a sharp, and usually infected object the point of which is not infrequently left either in the bone or inside the skull. Fragments of bone are often driven into the brain, and short fissures frequently pass in various directions from the central aperture.

Diagnosis.—When the instrument impinges on the head obliquely, after piercing the scalp it may pass for some distance under it before perforating the skull, so that on its withdrawal a valvular wound is left, and at first sight it appears that only the scalp is involved. Sometimes a foreign body left in the gap so fills it up that it is difficult to detect the fracture with a probe or even with the finger. In all doubtful cases the scalp wound should be sufficiently enlarged to exclude such errors. We have known of a case of a man who died of meningitis resulting from a punctured fracture of the vault caused by the spoke of an umbrella, the fracture having escaped recognition until the meningeal symptoms developed.

Treatment.—The scalp wound must be purified, being opened up as far as necessary for this purpose. The infected portion of bone should be removed to render possible the purification of the membranes and brain, and to permit of drainage.

Depressed and Comminuted Fractures.—As these varieties almost always occur in combination, they are best considered together. The terms "indentation fracture," "gutter fracture," "pond fracture," have been applied to different forms of depressed fracture, according to the degree of damage to the bone and the disposition of the fragments (Figs. 188, 189, 190). These fractures may be simple or compound.



As a rule the whole thickness of the skull is broken, and, as usual, the inner table suffers most. In infants the bones may be merely indented, the fracture being of the greenstick variety. All degrees of severity are met with, from a simple, localised indentation of the bone, to complete smashing of the skull into fragments.

Diagnosis.—When compound, the nature of these fractures is readily recognised on exploring the wound, but their extent is not always easy to determine, and it is not uncommon for extensive fissures to pass into the base.

A haematoma of the scalp may readily be mistaken for a depressed fracture. The condensation of the tissues round the seat of impact and the soft coagulum in the centre, closely simulate a depression in the bone; but if firm pressure is made with the finger, the irregular edge of the bone can be recognised, and the depressed portion is felt to be on a lower level. On the other hand, a depression in the bone is sometimes obscured by an overlying haematoma, and unless great care is taken the fracture may be overlooked.

Treatment.—All are agreed that compound depressed and comminuted fractures—whether associated with cerebral symptoms or not—should be operated on to enable the wound to be purified, and the normal outline of the skull to be restored by elevating or removing depressed or separated fragments. Except in young children, in whom considerable degrees of depression are frequently righted by nature, most surgeons recommend operative interference even in simple fractures with the object of elevating the depressed bone, and to anticipate subsequent complications such as persistent headache, attacks of giddiness, traumatic epilepsy, or insanity. Others, including von Bergmann and Tilmanns, consider that the risk of such sequelae ensuing is not sufficient to justify a prophylactic operation of such severity as trephining.

The operation is described in Operative Surgery, p. 93.

FRACTURES OF THE BASE

The base of the skull may be fractured by a pointed object, such as a fencing foil, a knitting pin, or the end of an umbrella, being forced through the orbit, the nasal cavities, or the pharynx. These injuries will be referred to in describing fractures of the anterior fossa.

The majority of basal fractures result from such accidents as a fall from a height, the patient landing on the vertex or on the side of the head, or from a heavy object falling on the head. The violence is therefore indirect in so far as the bone breaks at a point other than the seat of impact.

In other cases the base is broken by the patient falling from a height and landing on his feet or buttocks, the force being transmitted through the spine to the occiput, and the bone giving way around the foramen magnum. Sometimes the condyle of the lower jaw is driven through the base of the skull by a blow or fall on the chin, and fissures radiate into the base from the glenoid cavity. It is usual to describe these also as fractures by indirect violence, but as the skull gives way at the point where it is struck, these are really fractures by direct violence. Von Bergmann, Bruns, and Messerer have done much to elucidate the mechanism of basal fractures.

In the consideration of the mode of production of basal fractures by indirect violence, the irregular shape of the cavity, the varying strength and thickness of its different parts, and the existence of the foramina through the bone are to be borne in mind. The force acting on the skull tends to increase one diameter of the cavity, and to diminish the opposite diameter. The resulting fracture, therefore, is due to bursting of the skull, and tends to take place at the part which has least elasticity—that is, at the base. It has been found that the site and direction of basal fractures bear a fairly constant relation to the direction of the force by which they are produced. When, for example, the skull is compressed from side to side, the line of fracture through the base is usually transverse, and it may implicate one or both sides (Fig. 191). On the other hand, when the pressure is antero-posterior, the fracture tends to be longitudinal; and when oblique, it tends to be diagonal.



Fractures of the base usually take the form of a single fissure, or a series of fissures, which, as a rule, run through the foramina in their track. Small portions of bone are sometimes completely separated. It is common for a fissure through the base to be continued for a considerable distance on to the vault.

The fracture may involve only one fossa, but as a rule fissures radiate into two or all of them. Fractures of the anterior and middle fossae are usually rendered compound by tearing of the mucous membrane of the nose, the pharynx, or the ear.

Basal fractures are frequently associated with contusion and laceration of the brain, and also with injuries of one or more of the cranial nerves.

Fracture of the anterior fossa may result from a blow on the forehead, nose, or face; or from a punctured wound of the orbit or of the nasal cavity. Often the injury is at first considered trivial, and it is only when infective complications, in the form of meningitis or cerebral abscess, develop, that its true nature is suspected. This fossa may also be implicated in fractures of the vault, fissures extending from the vertex to the orbital plate of the frontal bone, or to the lesser wing of the sphenoid.

Clinical Features.—Unless the fracture is compound through opening into the nose or pharynx, there are few symptoms by which it can be recognised. When compound, there may be bleeding from the pharynx or nose from tearing of the periosteum and mucous membrane related to the basi-sphenoid and ethmoid respectively. When the haemorrhage is profuse, it is probable that the meningeal vessels or even the venous sinuses have been torn. Cerebro-spinal fluid may escape along with the blood, but it is seldom possible to recognise it. If the flow is long continued, the patient may be conscious of a persistent salt taste in the mouth, due to the large proportion of sodium chloride which the fluid contains. In very severe injuries, brain matter may escape through the nose or mouth.

Fracture of the anterior fossa is often accompanied by extravasation of blood into the orbit, pushing forward the eyeball and infiltrating the conjunctiva (sub-conjunctival ecchymosis). This occurs especially when the orbital plate of the frontal bone is implicated. The blood which infiltrates the conjunctiva passes from behind forwards, appearing first at the outer angle of the eye and spreading like a fan towards the cornea. Later it spreads into the upper eyelid. When the orbital ridge is chipped off, without the cavity of the skull being opened into, the haemorrhage shows at once both under the conjunctiva and in the upper lid. If the frontal sinus is opened, air may infiltrate the scalp.

The olfactory, optic, oculo-motor, pathetic, ophthalmic division of the trigeminal, and the abducens nerves are all liable to be implicated.

Diagnosis.—It is scarcely necessary to state that bleeding from the nose or mouth may occur after a blow on the face without the occurrence of a fracture of the skull. It is only when it is long continued and profuse that the bleeding suggests a fracture. Similarly effusion of blood in the region of the orbit may be due to a simple contusion of the soft parts ("black eye"), or to gravitation of blood from the forehead or temple. Sub-conjunctival ecchymosis also may occur independently of a fracture implicating the anterior fossa—for example, in association with an ordinary black eye, or with fracture of the orbital ridge or of the zygomatic (malar) bone.

Finally, paralysis of the cranial nerves may result from pressure of blood-clot, or from the nerves being torn without the skull being fractured.

Fracture of the middle fossa is usually the result of severe violence applied to the vault, as, for example, when a man falls from a height, or is thrown from a horse and lands on his head.

Clinical features.—The most conclusive sign of fracture of the middle fossa is the escape of dark-coloured blood in a steady stream from the ear, followed by oozing of cerebro-spinal fluid. The bleeding from the ear may go on for days, the blood gradually becoming lighter in colour from admixture with cerebro-spinal fluid. Finally the blood ceases, but the clear fluid continues to drain away, sometimes for weeks, and in such quantity as to soak the dressings and the pillow. In our experience, the escape of cerebro-spinal fluid is much less common than is generally supposed. In most cases, on examining the ear with a speculum, the tympanic membrane is found to be ruptured; when it is intact, the blood and cerebro-spinal fluid may pass down the Eustachian tube into the pharynx. The escape of brain matter from the ear is exceedingly rare. Emphysema of the scalp sometimes results when the fracture passes through the mastoid cells. The facial and acoustic nerves and the maxillary and mandibular divisions of the trigeminal are frequently implicated. Deafness is a serious and not uncommon accompaniment of fracture of the middle fossa, as the fracture involves the labyrinth and is attended with haemorrhage and the formation of new bone.

Diagnosis.—Care must be taken not to mistake blood which has passed into the ear from a scalp wound, or which has its origin in a fracture of the wall of the external auditory meatus or a laceration of the tympanic membrane, for blood escaping from a fracture of the base. Under these conditions the blood is usually bright red, is not accompanied by cerebro-spinal fluid, and the flow soon stops. It is on record[4] that blood and cerebro-spinal fluid may escape along the sheath of the acoustic nerve without the bone being broken.

[4] Miles, Edinburgh Medical Journal, 1895.

Fracture of the posterior fossa is produced by the same forms of violence as cause fracture of the middle fossa; it is specially liable to result if the patient falls on the feet or buttocks.

Clinical Features.—Sometimes a comparatively limited fracture of the occipital bone results, and in the course of a few days blood infiltrates the scalp in the region of the occiput and mastoid, or may pass down in the deeper planes of the neck. As a rule, however, there is no immediate external evidence of fracture. The patient is generally unconscious, and shows signs of injury to the pons and medulla, causing interference with respiration, which soon proves fatal. The rapidly fatal issue of these cases usually prevents the manifestation of any injury to the posterior cranial nerves.

Diagnosis of Basal Fractures.—In the diagnosis of fractures of the base, reliance is to be placed chiefly upon: (1) the nature of the injury; (2) the diffuse character of the cerebral symptoms; (3) the evidence of injury to individual cranial nerves; (4) the occurrence of persistent bleeding from the nose, mouth, or ear; (5) the extravasation of blood under the conjunctiva or behind the mastoid process; and (6) the presence of blood in the cerebro-spinal fluid withdrawn by lumbar puncture. In rare cases the diagnosis is made certain by the escape of cerebro-fluid or of brain matter from the nose, mouth, or ear.

It must be admitted, however, that in a large proportion of cases which end in recovery, the diagnosis of fracture of the base is little more than a conjecture. The external evidence of damage to the bone is so slight and so liable to be misleading, that little reliance can be placed upon it. The associated cerebral and nervous symptoms also are only presumptive evidence of fracture of the bone. In all cases, however, in which there is reason to suspect that the base is fractured, the patient should be treated on this assumption. It is often found that, when there are no cerebral symptoms present, it is difficult to convince the patient of the necessity for undergoing treatment, and of the risk involved in his leaving his bed and resuming work.

Prognosis in Basal Fractures.—The prognosis depends upon the severity of the cerebral lesions, and on the occurrence of traumatic oedema or infective intra-cranial complications. Many cases prove fatal within a few hours from the associated injury to the brain, the patient dying from cerebral compression due to haemorrhage. If the patient survives two days, the prognosis is more hopeful (Wagner). It is possible that the free escape of blood from the nose or ear may in some cases prevent compression, and to a certain extent render the prognosis more favourable. Punctured fractures are frequently fatal from infective complications—meningitis, sinus thrombosis, and cerebral abscess. These complications are also liable to occur in fractures rendered compound by opening into the nose, pharynx, or ear, but they are less common than might be expected.

Treatment.—The general treatment includes that for all head injuries. In a number of cases attended with symptoms of compression, benefit has followed the relief of intra-cranial tension by a decompression operation. The withdrawal of 30 or 40 c.c. of cerebro-spinal fluid by lumbar puncture has also proved beneficial in the same way; Quenu strongly recommends repeated puncture in serious cases. In a few cases this procedure has been followed by sudden death.

Steps must be taken to prevent infection from the mucous surfaces implicated. This is exceedingly difficult in fractures opening into the pharynx and nose. Owing to the general condition of the patient, it is usually impossible to employ nasal douching or mouth washes, but spraying the cavities with peroxide of hydrogen or other antiseptics may be employed with benefit. In fractures of the middle fossa, the ear should be gently sponged out and the meatus plugged with gauze, retained in position by adhesive plaster or a bandage. When there is a persistent escape of blood or cerebro-spinal fluid, the dressing requires to be changed frequently.

In compound fractures of the anterior fossa due to perforation through the orbit, the frontal bone should be trephined to admit of the removal of loose fragments or of any foreign body that may have entered the skull and to provide for drainage.



CHAPTER XIV

DISEASES OF THE BRAIN AND MEMBRANES

Pyogenic diseases—Meningitis: Varieties—Abscess: Varieties—Sinus phlebitis—Intra-cranial tuberculosis. Cephaloceles—Meningocele—Encephalocele— Hydrencephalocele—Traumatic cephal-hydrocele—Hydrocephalus; Varieties—Micrencephaly. Cerebral tumours. Tumours of the pituitary body. Epilepsy—Hernia cerebri. Surgical affections of cranial nerves—Cervical sympathetic.

PYOGENIC DISEASES

The most important intra-cranial conditions that result from infection with pyogenic bacteria are: meningitis, abscess of the brain, and phlebitis of the venous sinuses.

The organisms most frequently associated with these conditions are the staphylococcus aureus and the streptococcus, but it is not uncommon to meet with mixed infections in which other bacteria are present—particularly the pneumococcus, the bacillus foetidus, the bacillus coli, the bacillus pyocyaneus, and the diplococcus intracellularis.

By far the most common source of intra-cranial infection is chronic suppuration of the middle ear and mastoid antrum, the organisms passing from these cavities to the interior of the skull directly through a perforation of the tegmen tympani or of the wall of the sigmoid groove, or being carried in the blood stream by the emissary veins. In some cases the infection travels along the sheaths of the facial and acoustic nerves.

Less frequently infective conditions of the nasal cavity and its accessory air sinuses, and compound fractures of the skull, particularly punctured fractures, are followed by intra-cranial complications; or infection is conveyed to the inside of the skull, by way of the emissary veins, from wounds of the scalp, or from such conditions as erysipelas of the face and scalp, malignant pustule, carbuncles, or boils.

At the bedside there is often difficulty in discriminating between the various pyogenic intra-cranial complications, because many of the symptoms are common to all the members of this group, and because more than one condition is frequently present. Thus a localised meningitis spreading to the brain may set up a cerebral abscess; a sinus phlebitis may give rise to a purulent lepto-meningitis; or a cerebral abscess bursting into the sub-arachnoid space may produce meningitis.

MENINGITIS

Pachymeningitis.—This term is applied when the infection involves the dura mater—a condition which is usually due to the spread of infection from a localised osseous lesion, such as erosion of the tegmen tympani in chronic suppuration of the middle ear, of the wall of the sigmoid groove in mastoid disease, or of the posterior wall of the frontal sinus in suppuration of that cavity. It also occurs in relation to septic lesions of the cranial bones such as a broken-down gumma, after operations on the cranial bones, and in cases of compound fracture attended with a mild degree of infection and with imperfect drainage. In contusion of the skull without an external wound, the infection may take place through the blood stream.

The layer of the dura in contact with the affected portion of bone is inflamed, thickened, and covered with a layer of granulations—external pachymeningitis—and between it and the bone there is an effusion of fluid. Up to this point the process is largely protective in its effects, and gives rise to no symptoms, beyond perhaps some pain in the head.

In the majority of cases, however, suppuration occurs between the dura and the bone—suppurative pachymeningitis—and leads to the formation of an extra-dural abscess (Fig. 192). When this happens in association with disease in the middle ear or frontal sinus, it is attended with severe headache referred to the seat of the abscess, a sudden rise of temperature preceded by shivering, and other evidence of the absorption of toxins. Over the situation of the abscess, the scalp becomes swollen and oedematous—a condition which Percival Pott, in 1760, first observed to be characteristic of extra-dural suppuration, hence the name, Pott's puffy tumour, applied to it (Fig. 193). Under these circumstances the abscess is seldom of sufficient size to cause a marked increase in the intra-cranial tension, or to give rise to localised cerebral symptoms by pressing on the brain.



When associated with a punctured wound implicating the skull, an extra-dural abscess may develop within a few days of the injury, or not till after the lapse of several weeks, and it may spread over a wide area and come to encroach on the cranial cavity sufficiently to raise the intra-cranial tension and cause symptoms of compression, or even to press upon cortical centres and produce localised paralyses. As discharge can escape from the wound in the scalp, the puffy tumour does not necessarily form.

Treatment.—When the abscess is secondary to middle ear disease, the mastoid must be opened, the eroded bone exposed, and sufficient of it removed with rongeur forceps to admit of free drainage. When the infection has spread from the frontal sinus, the skull is trephined in the frontal region, the precise site being indicated by the oedematous area in the scalp, and the diseased bone is removed. In cases of compound fracture, drainage is established by enlarging the scalp wound, and removing loose, depressed, or inflamed portions of bone; if the bone is comparatively intact, it must be trephined, and further bone is removed with rongeur forceps over the entire area in which the dura has been separated.

Lepto-meningitis.—If the infection spreads to the adjacent arachno-pia (localised lepto-meningitis), adhesions usually form, and shut off the infected area from the general arachno-pial space.

Pus may form among these adhesions, constituting a sub-dural abscess, and may infiltrate the superficial layers of the cortex (purulent encephalitis, or meningo-encephalitis) (Fig. 194). The symptoms are similar to those of extra-dural abscess, but may be more severe; and it is seldom possible to distinguish between them before exposing the parts by operation. The treatment is carried out on the same lines.



Acute General Lepto-Meningitis.—In bone lesions, particularly compound fractures, infection of the arachno-pia may take place before protective adhesions form, and a diffuse lepto-meningitis results. The open structure of the arachno-pial membrane favours the rapid spread of the infection, which may extend over the surface of the hemispheres, or downwards towards the base (basal meningitis), or in both directions. The process is at first attended with a copious effusion of cerebro-spinal fluid into the arachno-pial space and into the ventricles (serous lepto-meningitis), but this fluid tends to become purulent, the pus forming in a thin layer over the surface of the brain, and in the sulci between the convolutions (purulent lepto-meningitis). The membranes are congested and thickened, the veins of the arachno-pia engorged, and the superficial layers of the cortical grey matter may share in the process (encephalitis).

Clinical features.—The earliest and most prominent symptom is violent pain in the head, often referred to the frontal region, or, in cases starting from middle ear disease, to the temporal region. This is accompanied by a sudden rise of temperature, usually without an antecedent rigor; the temperature remains persistently elevated (102 deg. to 105 deg. F.), and the pulse is small, rapid, and irregular both in rate and force. The patient, especially if a child, is extremely irritable, all his sensations are hyper-acute, and he periodically utters a peculiarly sharp, piercing cry.

Vomiting of the cerebral type—that is, unattended with nausea and not related to the taking of food or to gastric disturbance—is common, and persists through the illness. The bowels are usually constipated. There is an increase in the number of leucocytes in the cerebro-spinal fluid, and organisms also are found in the fluid. As this does not occur in cerebral abscess, examination of the cerebro-spinal fluid may be useful in differential diagnosis. There is a higher leucocytosis in the blood in meningitis than in cerebral abscess.

When the inflammation is most marked over the cerebral hemisphere, there may be paralysis of the side of the body opposite to the seat of the original lesion; sometimes there is erratic rigidity of the limbs, sometimes clonic spasms of groups of muscles. The superficial reflexes disappear early on both sides; the abdominal reflexes being lost sooner than the knee-jerks. In basal meningitis, temporary squinting due to irritation of the ocular muscles, retraction of the head, and an excessively high temperature are usually prominent features. The pupils at first are equally contracted; later they become dilated and fixed. Both optic discs are oedematous and swollen.

Gradually the patient becomes unconscious, shows signs of increasing intra-cranial tension, slowing of the pulse, and laboured respiration, and the condition almost always proves fatal within three or four days.

Treatment.—The treatment consists in removing the source of infection when this is possible, but as a rule little can be done to arrest the spread of the meningitis or to ward off its effects. In cases resulting from a sub-dural abscess in relation to a compound fracture, a sinus phlebitis, or an erosion of the tegmen tympani, an attempt should be made, after exposing this, to purify and drain the meningeal spaces. Temporary relief of symptoms sometimes follows the withdrawal of cerebro-spinal fluid by repeated lumbar puncture, bleeding by leeches or cupping, or the use of an ice-bag or Leiter's tubes. The bowels should be freely moved by purgatives or enemata.

Cerebro-spinal Meningitis.—This form of meningitis, which is due to the diplococcus intracellularis, may occur sporadically, but is more frequently met with in an epidemic form. It is attended with the formation of a profuse sero-purulent exudate, which covers the brain, the cord, the nerves, and the membranes.

The clinical features are similar to those of acute general lepto-meningitis, and in sporadic cases the diagnosis is only completed by discovering the diplococcus intracellularis in the fluid withdrawn by lumbar puncture. Although recovery sometimes takes place, the disease is attended with a high mortality. In the early stages, before the exudate has become too thick, repeated lumbar puncture followed by the injection of Flexner's serum has proved beneficial. Recovery may be attended with paralysis of one or other of the cranial nerves.

CEREBRAL AND CEREBELLAR ABSCESS

Abscess due to Middle Ear Disease.—The most common cause of abscess in the brain is chronic middle ear disease, and the majority of cerebral abscesses are therefore situated in the temporal lobe. Some are due to direct spread from a collection of pus in relation to an erosion of the tegmen tympani, either inside or outside the dura, others to infection carried by the veins, and in this way the infective material reaches the white matter; less frequently infection from the middle ear takes place along the peri-vascular lymph spaces. Macewen has pointed out that cerebral abscess never occurs from pyogenic organisms passing from the middle ear by way of the internal auditory meatus, although lepto-meningitis may do so. Cerebral abscess is much more frequently met with in the white matter of the centrum ovale than in the cortex, and in the majority of cases the abscess is single.

The pus is often of a greenish-yellow colour, or it may be dark brown from admixture with broken-down blood-clot; in some cases it is thin and serous and contains sloughs of brain matter, and it frequently has a foetid odour. In quantity it varies from a few drops to several ounces.

The arachno-pia over an abscess usually has a turbid and milky appearance.

In an acute abscess the surrounding brain tissue is engorged and infiltrated with pus; in a chronic abscess it is condensed, and the pus may be encapsulated by the formation of a zone of young fibrous tissue round its periphery. In this condition the abscess may remain "latent," giving rise to no symptoms for many weeks or even months.

Clinical features.—The initial formation of pus in the cerebral tissue is associated with the sudden onset of severe pain in the head, shivering and well-marked cutis anserina, and vomiting of the cerebral type. The discharge from the ear usually diminishes or may even cease.

As a localised abscess develops the patient gradually passes, into a stuporous condition; he does not lose consciousness, but, his cerebration is slow, he seems unable to sustain his attention, for any length of time, and he answers questions "slowly, briefly, but, as a rule, correctly" (Macewen). The pain in the region of the ear becomes less intense, but the mastoid and temporal areas on the affected side are tender on percussion. The temperature falls, and, as a rule, remains subnormal. Rigors are unusual: their occurrence usually indicating the development of some complication such as sinus phlebitis. The pulse is full, regular, and slow (40 to 60). Vomiting frequently occurs, and the bowels are often obstinately constipated.

There is no actual paresis, but there is a "gradual diminution of the ability to apply his strength." The superficial reflexes are late of disappearing and the disturbance is unilateral. The optic discs are moderately swollen. "The face is expressionless, passive, and cloudy. It may assume a meaningless smile, with which the features are not lit; it is too mechanical" (Macewen).

Differential Diagnosis.—In the early stages it is often difficult to distinguish between meningitis and cerebral abscess. The chief points on which reliance is to be placed are that in meningitis the pulse shows an irregularity, both in rate and force, which is wanting in cases of uncomplicated abscess. In meningitis the temperature is raised, while in abscess it is persistently subnormal. The superficial reflexes, particularly the abdominal reflexes, disappear early in meningitis and the disturbance is bilateral; in abscess they are slower to disappear, and one side only is affected. Retraction of the neck, when present, is a characteristic sign of meningitis. In meningitis the optic discs are highly oedematous and are more swollen than in abscess, and the condition is equally marked on the two sides.

Localisation of Cerebral Abscess—Temporal Abscess.—The existence of middle ear disease is always presumptive evidence that the abscess is in the temporal lobe on the same side. A small abscess in this lobe may produce no localising symptoms; one of large size may press indirectly on the motor cortex, on the fibres passing through the internal capsule, or on individual cranial nerves.

It is important to observe the order in which paralysis of the opposite side of the body comes on. When it begins in the face and passes successively to the arm and leg, the pressure is on the cortical centres. When the paralysis progresses in the opposite direction—leg, arm, face—the pressure is on the nerve fibres passing through the internal capsule (Fig. 195). The paralysis may be spastic in lesions of the cortex or internal capsule; if it is flaccid the lesion is almost certainly cortical.



Motor aphasia may result from pressure on the left inferior frontal convolution; auditory aphasia from abscess in the posterior part of the superior temporal convolution. Ptosis and lateral squint, with a fixed and dilated pupil, indicates pressure on the oculo-motor nerve of the same side.

Abscess in the parietal lobe gives rise to paralysis of the face and limbs on the opposite side of the body. Abscess in the occipital lobe produces interference with the visual functions. An abscess in the frontal lobe may give rise to no localising symptoms, but if it is on the left side, the power of making co-ordinated movements may be lost—apraxia—or the motor speech centre may be implicated.

Terminal Stage.—If left to itself, a cerebral abscess usually ends fatally by causing gradually increasing stupor and coma, or by bursting, either into the ventricles or into the sub-arachnoid space, and setting up a diffuse purulent lepto-meningitis.

When the abscess bursts into the ventricles, the patient suddenly becomes much worse and dies within a few hours. "The pupils become widely dilated, the face livid, the respiration greatly hurried, and either shallow or stertorous. The temperature rises within a few hours with a bound from subnormal to 104 deg. to 105 deg. F.; the pulse from 40 or 50 per minute quickly reaches 120 and over. There are muscular twitchings all over the body, possibly associated with convulsions and tetanic seizures, and these are followed by coma and speedy death" (Macewen).

Spontaneous evacuation of a temporal abscess may take place through the middle ear.

Cerebellar Abscess.—Next to the temporal lobe, the cerebellum is the most common seat of abscess. Cerebellar abscess is usually due to spread of infection from a thrombosed sigmoid sinus, either directly from a sub-dural abscess formed in relation to the walls of the sinus, or by extension of the thrombotic process along the cerebellar veins. While the abscess is small, it may give rise to few symptoms, and the patient may be able to go about, but as it increases in size serious symptoms develop. There may be nystagmus, and the patient suffers from vertigo, and is unable to co-ordinate his movements. If he attempts to walk, he reels from side to side; even when sitting up in bed, he may feel giddy and tend to fall, usually towards the side opposite to that on which the abscess is situated. The head and neck are retracted, the pulse is slow and weak, and the temperature subnormal. There is frequent yawning, and the speech is slow, syllabic, and jerky. There may be optic neuritis and blindness. There is sometimes unilateral or even bilateral spastic paralysis of the limbs from pressure on the medulla oblongata. The respiration may assume the Cheyne-Stokes character, occasionally being interrupted for a few minutes, while the heart continues to beat vigorously. This arrest of respiration is especially liable to occur during anaesthesia.

Treatment.—The abscess having been localised, the skull must be opened and the pus removed.

Abscess from causes other than Middle Ear Disease.—From the nasal passages, infection may spread to the interior of the skull directly through the walls of the frontal, ethmoidal, or sphenoidal air sinuses, or indirectly by way of the veins, and give rise to a cerebral abscess, usually in the frontal lobe. The symptoms are similar to those of abscess following middle ear disease, but focal symptoms are seldom present. When the abscess is on the left side, apraxia and motor aphasia may be present. Spontaneous evacuation may take place by the abscess bursting into the nose through the cribriform plate.

The treatment consists in trephining through the frontal bone or through the temporal fossa, according to the site of the abscess and its seat of origin. The primary focus of infection must also be dealt with.

In infected compound fractures, an abscess may form in the cortical grey matter within a few days of the injury from direct spread of infection from the bone and membranes. This is usually associated with a spreading lepto-meningitis, the symptoms of which predominate. The condition usually proves fatal, but by opening up the original wound, removing depressed fragments of bone, and establishing drainage, the patient's life may be saved.

There is evidence that an abscess may form in the brain after a simple contusion without fracture or other external injury (Ehrenvooth).

An abscess may develop in the white matter of the centrum ovale some weeks, or even months, after an injury, particularly if a fragment of bone or a foreign body has been driven into the brain. If the infection has spread along the track of the missile, the abscess is usually near to the seat of the brain injury, but if it is due to spread of a thrombo-phlebitis it may be a considerable distance from it, even on the opposite side of the head. These chronic abscesses are usually in the parietal or frontal lobes, and as the pus is encapsulated they may remain latent for long periods, during which they may cause some degree of headache, neuralgic pains in the distribution of the trigeminal nerve, and occasional rises of temperature. When the abscess becomes active, general symptoms similar to those of other forms of abscess develop, and there may be localised paralysis of the opposite side of the body, the distribution of which depends upon whether the cortical centres or the motor fibres are implicated.

The treatment consists in opening up the original wound, removing any depressed bone or foreign body that may be present, and establishing drainage.

Bronchiectasis and other infective diseases of the lungs are less common causes of cerebral abscess, which is usually single, and may occur in any part of the brain.

Disease of the bones of the skull, such as osteomyelitis or syphilis, may be followed by cerebral abscess.

Abscesses of pyaemic origin are usually multiple, and may occur both in the cerebrum and in the cerebellum; they are not amenable to surgical treatment.

SINUS PHLEBITIS

Inflammation of the intra-cranial venous sinuses is due to the spread of infection from a local focus of suppuration; by far the most frequent cause is chronic suppuration in the middle ear. Less common sources of infection are erysipelas of the face or scalp, infective conditions of the mouth or nose, and diseases of the bones of the skull.

The organisms may reach the affected sinus directly by continuity of tissue, as, for instance, when the transverse (lateral) sinus becomes infected from a focus of suppuration in the mastoid process spreading through the bone to the sigmoid groove and involving the walls of the vessel; or they may reach it by extension of thrombosis in a tributary vein—for example, when the superior sagittal (longitudinal) sinus is infected from an anthrax pustule of the lip, which has caused thrombosis of the emissary vein that passes through the foramen caecum.

The pathological changes are the same as occur in the suppurative form of thrombo-phlebitis in the peripheral veins (Volume I., p. 285). The soft clot that forms adheres to the inflamed wall of the sinus, and, being infected with pyogenic bacteria, it soon undergoes purulent disintegration.

The infective process may spread backward along tributary vessels, and so give rise to cerebral or cerebellar abscess, or to purulent meningitis; or it may spread into the internal jugular vein and lead to the development of a diffuse purulent cellulitis along its course.

General pyaemic infection may take place from pus or bacteria getting into the circulation, either directly or by reversed flow through tributary veins. Infective emboli are liable to lodge in the lung or pleura, and set up pulmonary abscess, gangrene of the lung, or empyema.

Clinical Features.—In all cases, pain in the head, referred to the region of the affected sinus, and so severe as to prevent sleep, is an early and prominent feature. The patient is usually excited, hypersensitive, and irritable in the early stages, and becomes dull and even comatose towards the end. Rigors, followed by profuse perspiration, occur early and increase in frequency as the disease progresses. The temperature is markedly remittent, varying from 103 deg. to 106 deg. F. (Fig. 196). The pulse is rapid, small, and thready. Loss of appetite, vomiting, and diarrhoea are almost constant symptoms.



Phlebitis of Individual Sinuses.—The transverse (lateral or sigmoid sinus), from its proximity to the middle ear and mastoid air cells, is that most commonly affected, especially in young adults. With the onset of the phlebitis the discharge from the ear stops; there is severe pain in the ear and violent headache. The temperature rises, but shows marked remissions, and rigors are common. Vomiting is frequently present. Turgescence of the scalp veins draining into this sinus, and oedema over the mastoid, are occasionally observed; but as these signs may accompany various other conditions, they are of little diagnostic value. Not infrequently phlebitis spreads to the internal jugular vein, which may then be felt as a firm, tender cord running down the neck, and the head is held rigid, sometimes in the position characteristic of wry-neck.

Three clinical types of sinus phlebitis are recognised—pulmonary, abdominal, and meningeal—but it is often impossible to relegate a particular case to one or other of these groups. Many cases present symptoms characteristic of more than one of the types.

In the pulmonary type evidence of infection of the lungs appears towards the end of the second week, in the form of dyspnoea, cough, and pain in the side, coarse moist rales, and dark foetid sputum. Death usually takes place from gangrene of the lung. The brain functions may remain active to the end.

In the abdominal type the symptoms closely resemble those of typhoid fever, for which the condition may be mistaken. The absence of a rash and the coexistence of middle ear disease are important factors in diagnosis.

When the disease is of the meningeal type, symptoms of general purulent lepto-meningitis assert themselves, and soon come to dominate the clinical picture. Evidence of the presence of meningitis may be obtained by lumbar puncture. The mind at first is clear, but the patient is irritable; later he becomes comatose.

The prognosis is always grave, on account of the risk of general infection.

Treatment.—The primary focus of infection must first be removed, and this usually involves clearing out the middle ear and mastoid process. The sigmoid sinus is then exposed, and after any granulation tissue or pus that may be in the groove has been cleared away, the sinus is opened and the thrombus removed. With the object of preventing the dissemination of infective material, a ligature should be applied to the internal jugular vein in the neck before the sinus is opened, as was first recommended by Victor Horsley. If the phlebitis is accompanied by other intra-cranial infections, these are, of course, treated at the same time.

The superior sagittal or longitudinal sinus is liable to be infected from pyogenic lesions of the scalp. There are no symptoms that are pathognomonic, but oedema of the scalp with turgescence of its veins, epistaxis, and convulsions followed by paralysis, are those most likely to be met with.

The cavernous sinus is usually implicated by spread of the process from other sinuses—for instance, from the petrosal or transverse (lateral) sinuses—or from the ophthalmic veins in cases of orbital cellulitis. Although at first unilateral, the thrombosis usually spreads across the middle line to the sinus of the opposite side. The special symptoms—exophthalmos, oedema of the eyelids, and paralysis of the ocular nerves—are due to pressure on the structures entering the orbit.

Operative interference is seldom feasible in phlebitis of the superior sagittal (longitudinal) or cavernous sinuses.

Intra-cranial Tuberculosis.—Tuberculous meningitis is most frequently met with in patients below the age of twenty, and the infection takes place by the blood stream from some focus elsewhere in the body or from the spinal membranes. In cases of tuberculous disease of the middle ear infection may spread to the membranes by way of the internal auditory meatus (Macewen). The arachno-pia, especially at the base, is studded over with miliary tubercles, and an excess of fluid collects in the arachno-pial space and in the ventricles (acute hydrocephalus).

At first the symptoms of irritation of the brain predominate: severe headache, photophobia, inequality of the pupils, stiffness of the neck, cutaneous hyperaesthesia, vomiting and convulsions. Kernig's sign—pain on flexing the hip while the knee is extended, and inability to extend the knee while in the sitting posture—is present. There is usually obstinate constipation, and the abdomen is retracted. Later, signs of increased intra-cranial tension develop: unconsciousness deepening into coma, paralysis of ocular muscles, rapid pulse, Cheyne-Stokes respiration, and sometimes hyperpyrexia. An excess of mono-nuclear lymphocytes and, sometimes, tubercle bacilli may be discovered in the cerebro-spinal fluid withdrawn by lumbar puncture. The absence of the diplococcus intracellularis helps to differentiate the disease from cerebro-spinal meningitis, which it may closely simulate.

The only surgical measure that is justifiable is lumbar puncture, which often affords marked relief of symptoms, although the benefit is only temporary.

Localised tuberculous nodules sometimes develop in the brain and form definite tumours. They vary in size from a pea to a hen's egg, are rounded and encapsulated. Sometimes the centre is caseous, sometimes fibrinous or calcified. In children they are usually multiple; in adults they may be single—the so-called "solitary tubercle." They are most common in the pons, basal ganglia, and cerebellum, but occur also in the cerebral cortex and sometimes in the centrum ovale. They usually originate in the pia and invade the brain substance, but do not as a rule involve the dura. The membranes in the vicinity of the growth are often the seat of tuberculous disease.

As these nodules give rise to the same symptoms as other forms of cerebral tumour, and as their nature can be diagnosed only in exceptional cases, their clinical features and treatment are described with tumours of the brain.

Intra-cranial Syphilis.—Syphilitic meningitis is usually secondary to cario-necrosis of the bones of the vault or to a localised gumma of the brain. When primary, it usually affects the inter-peduncular region of the base, and takes the form of a diffuse gummatous infiltration of the membranes which gives rise to symptoms referable to the parts pressed upon, and especially paralysis of one or other of the cranial nerves. As in other intra-cranial syphilitic lesions, the symptoms show a variability in intensity which is characteristic. The diagnosis is made by the history, and the treatment is carried out on the same lines as in other syphilitic lesions.

Localised gummata are described with tumours of the brain.

CEPHALOCELES

The term "cephalocele" is applied to a protrusion of a portion of the cranial contents through a congenital deficiency in the bones of the skull. This malformation is believed to be due to an irregularity in development, whereby a portion of the primary cerebral vesicle remains outside the mesoblastic layer of the embryo. It is usually associated with adhesion of the membranes in the region of the fourth ventricle, and with internal hydrocephalus. Cephaloceles are covered by the scalp, and are most commonly met with in the occipital region and at the root of the nose; less frequently at the anterior inferior angle of the parietal bone, and in the line of the sagittal suture. Very rarely they occur at the base of the skull and project into the pharynx, the mouth, or the nose, where they are liable to be mistaken for polypi. Cephaloceles vary greatly in size, some being so small as almost to escape detection, while others are larger than a child's head. In many cases the condition is incompatible with life.

Several varieties are recognised. They are known as (1) meningocele, which consists of a protrusion of a cul-de-sac of the arachno-pial membrane, containing cerebro-spinal fluid; (2) encephalocele, in which a portion of the brain is protruded in addition to the membranes; and (3) hydrencephalocele, in which the protruded portion of brain includes a part of one of the ventricles.

Clinical Features.—The meningocele is commonest in the occipital region, where it escapes through a cleft in the bone between the foramen magnum and the occipital protuberance (Fig. 197). It forms a tense, smooth, translucent globular swelling, which may be sessile or pedunculated, and is usually covered by thin, smooth skin in which the vessels are dilated and naevoid. The tumour does not pulsate, but increases in size and tension when the child cries or coughs. It may be diminished in size or even made to disappear by pressure, and so permit of the opening in the bone being felt. This manipulation, however, may be followed by slowing of the pulse, vomiting, loss of consciousness, or convulsions.



Small meningoceles may remain stationary for a long time, or may even undergo spontaneous cure. Those of larger size usually progress till they eventually burst, and death results from the escape of the cerebro-spinal fluid or from meningitis. Infection may also occur from eczema or from excoriation of the overlying skin.

Encephaloceles are much commoner than meningoceles, and usually occur in the frontal region, where they form broad-based, elastic, and pulsatile tumours, which vary greatly in size.

The hydrencephalocele is usually met with in the occipital region, and is generally so large and associated with such great cerebral deformity as to be inconsistent with life. It does not as a rule pulsate (Fig. 198).



Cephaloceles have to be diagnosed from dermoid cysts, naevi (Fig. 199), cephal-hydrocele, and cephal-haematoma. Their recognition is seldom attended with difficulty. If the margins of the gap in the skull can be distinctly felt, or the gap in the bone can be shown by the X-rays, the diagnosis is greatly simplified.



Treatment.—Only small cephaloceles are amenable to surgical treatment; those that are large and contain brain substance are best left alone, being merely protected from irritation and infection.

While the immediate effects of operation are, on the whole, satisfactory, the ultimate results are disappointing, as the essential cause of the intra-cranial pressure persists, and the child develops hydrocephalus. The method of tapping the sac and injecting iodine has nothing to recommend it.

Traumatic Cephal-hydrocele.—Certain rare cases of simple fracture of the vault occurring in early childhood have been followed by the development beneath the scalp of a localised fluid swelling, which varies in size from time to time and is partly reducible by pressure. The swelling results from laceration of the membranes, and sometimes of the brain substance, so that the cerebro-spinal fluid of the sub-arachnoid space, or even of the lateral ventricle, escapes through the opening in the skull and bulges beneath the scalp. In a majority the swelling pulsates synchronously with the heart, and becomes tense on exertion. A distinct opening in the skull may sometimes be felt. When associated, as it frequently is, with mental deficiency or the occurrence of fits, the cyst may be tapped or its neck ligated (Hogarth Pringle). Otherwise it should be left alone.

HYDROCEPHALUS

An excess of cerebro-spinal fluid may collect in the arachno-pial space surrounding the brain, or in the interior of the ventricles, constituting in the former case an external, and in the latter an internal hydrocephalus. Hydrocephalus may be acute or chronic.

Acute hydrocephalus is practically synonymous with tuberculous meningitis, although it may result from other forms of meningeal infection. The excess of fluid is found both in the arachno-pial space and in the ventricles. This condition only calls for mention here as attempts have been made to treat it by surgical measures, such as lumbar puncture, or drainage through the occipital fossa. The results, however, have not been encouraging.

Chronic Hydrocephalus.—Chronic external hydrocephalus is rare, and usually results from some definite intra-cranial lesion, such as meningitis, tumour, or cerebral atrophy. It is not amenable to surgical treatment.

Chronic internal hydrocephalus, on the other hand, is a comparatively common condition. It may be of congenital origin, or may develop in young rickety children, usually as a result of some chronic inflammatory process in the membranes at the base, the choroid plexuses, or the ependyma of the ventricles, causing obstruction to the outflow of blood through the internal cerebral veins of Galen. In the acquired form the communication between the ventricles and the sub-arachnoid space, by way of the foramen of Magendie, is obstructed, so that the cerebro-spinal fluid is pent up in the ventricles and gradually distends them. The pressure causes the head to enlarge, the fontanelles to bulge, and the bones to be separated from one another, the interval between the bones being occupied by a thin translucent membrane.

The cerebral tissue is greatly thinned out, but the cerebellum and cranial nerves usually remain unaffected.

The appearance of the patient is characteristic (Fig. 200). The enormous dome of the skull surmounts a puny and preternaturally old face; the eyes are pushed downwards and forwards by the pressure on the orbital plates, and the eyebrows are displaced upwards. The head rolls helplessly from side to side; the child moans and cries a great deal; and vomiting is often a prominent symptom. In most cases the intelligence is defective, and epileptic seizures and other functional disturbances of the brain may be present.



In mild cases, especially when associated with rickets or syphilis, recovery sometimes takes place, but in the majority the condition progresses, and death results either from convulsions or from some intercurrent disease. Few hydrocephalic subjects reach adult life.

Treatment.—Hydrocephalus being a symptom rather than a disease, no method of treatment which does not remove the primary cause can be permanently curative. Anti-syphilitic treatment should be tried in the hydrocephalus of infants and young children. The rachitic element, when present, must also be treated.

In congenital hydrocephalus, as there is no blocking of the passages at the fourth ventricle, the foramina being as a rule much larger than normal, no form of drainage is beneficial. Ligation of the common carotids, one some weeks after the other, has been successful in restoring the balance which normally exists between the secretion and absorption of the cerebro-spinal fluid (H. J. Stiles). In acquired hydrocephalus, puncture of the ventricles is sometimes followed by a remarkable improvement in the symptoms, and may even result in apparent cure. An exploring needle is introduced at the lateral angle of the anterior fontanelle, to avoid the superior sagittal (longitudinal) sinus, and from a half to one ounce of cerebro-spinal fluid withdrawn. This is repeated once a week for several weeks. Continuous drainage of the fourth ventricle through an opening made in the occipital region (Parkin), and the establishment of a communication between the ventricle and sub-arachnoid space (Watson-Cheyne), or between the sub-arachnoid space of the spinal cord and the peritoneal cavity, or the retro-peritoneal space (Cushing), have been tried, with little more than temporary benefit in the majority of cases. Operative treatment, if it is to do good, must be undertaken early, before permanent changes in the brain have taken place.

Micrencephaly.—This condition is due to defective development of the brain, and not to premature closure of the cranial sutures and fontanelles, and as the subjects of it are mentally deficient, and often blind, deaf and dumb, the removal of segments of the skull with a view to enable the brain to develop have proved futile.

CEREBRAL TUMOURS

As a comparatively small proportion of tumours of the brain—using the term "tumour" in its widest sense—are amenable to surgical treatment, it is only necessary here to refer to those aspects of this subject that have a distinctively surgical bearing.

Various forms of growth occur in the brain, the most common being tuberculous nodules, syphilitic gumma, endothelioma, glioma, and sarcoma. Less frequently fibroma, osteoma, and parasitic, haemorrhagic, and other cysts are met with. The growth may originate in the brain tissue primarily, or may spread thence from the membranes, or from the skull. In relation to operative treatment, it is an unfortunate fact that those forms that are well defined and do not tend to infiltrate the brain tissue, usually occur at the base, where they are difficult to reach; while those that develop in more accessible regions are for the most part infiltrating growths of a gliomatous or sarcomatous nature, and are therefore irremovable.

Clinical Features.—The presence of a tumour in the brain inevitably results sooner or later in an increase in the intra-cranial tension, and to this the symptoms are chiefly due.

The earliest and most prominent of the general symptoms are severe paroxysmal headache, optic neuritis, with choked disc and limitation of the field for blue, amounting sometimes to blue-blindness (Cushing). The relative degree of neuritis in the two eyes is a reliable guide to the side on which the tumour is situated (Horsley). The symptoms are seldom absent, and are common to all forms of tumour, wherever situated. Vomiting, which is without relation to the taking of food and is usually unattended by nausea, is a characteristic symptom when present, but it is wanting in two-thirds of the cases (Cushing). Vertigo, general convulsions, and signs of mental deterioration are also present in a considerable proportion of cases.

In addition, certain localising symptoms may be present. When, for example, the tumour is situated in the cortex of the Rolandic area, attacks of Jacksonian epilepsy, preceded by an aura, which is usually referable to the centre primarily implicated, are common. The group of muscles first involved, and the order in which other groups become affected, are important localising factors. As the tumour increases in size, these irritative phenomena are replaced by localised paralyses. The tactile and muscular sensations are also disturbed, and motor and sensory aphasia may be present. In some cases localised tenderness on percussing the skull may be of assistance in indicating the site of the tumour.

When the tumour is sub-cortical, that is, in the centrum ovale, there are no Jacksonian spasms, the motor paralysis is more widespread, and sensation also is lost on the opposite side of the body. There is no special tenderness on percussion. It is not always possible, however, to distinguish between cortical and sub-cortical tumours, and in many cases both areas are invaded.

Tumours situated in the region of the internal capsule, and in the deeper parts of the brain, are not attended with Jacksonian spasms, paralysis develops more rapidly than in cortical and sub-cortical tumours, and there is complete loss of sensation on the opposite side of the body. The cranial nerve-trunks also are liable to be pressed upon.

Tumours and cysts in the cerebellum give rise to symptoms similar to those of cerebellar abscess (p. 381).

Tumours in the cerebello-pontine angle, in addition to the special symptoms associated with cerebellar lesions, give rise to symptoms of interference with nerve-roots of the same side. The facial and acoustic nerves are most frequently affected, resulting in facial weakness, tinnitus, loss of perception for high-pitched notes, as tested by Galton's whistle, or absolute unilateral deafness. Any of the other cranial nerves from the fifth to the twelfth may be either irritated or paralysed. Pressure on the pons may produce hemiplegia of the opposite side, with spasticity and exaggeration of reflexes. Sudden death may occur from crowding of the cerebellum into the foramen magnum.

With the growth of the tumour the symptoms become aggravated, the optic neuritis is followed by optic atrophy and blindness, the patient gradually becomes stuporous, and finally dies in a state of coma. The severity of the symptoms depends to a large extent on the rapidity of growth of the tumour; thus an osteoma growing slowly from the inner table of the skull and implicating the brain may reach a considerable size without producing cerebral symptoms, while a comparatively small sarcoma or syphilitic gumma of rapid growth may endanger life. A sudden and serious aggravation of symptoms may result from haemorrhage into a soft tumour, such as glioma.

The diagnosis of the pathological nature of a cerebral tumour is generally "hardly more than a guess" (Gowers). At the same time it may be borne in mind that syphilitic gummata occur in adults, from forty to sixty years of age, who have suffered from acquired syphilis, and who may present other evidence of the disease. They tend to increase somewhat rapidly. A negative Wassermann reaction does not necessarily exclude a diagnosis of brain syphilis. Severe nocturnal pain which interferes with sleep is often a prominent symptom. Gummata are generally situated on the surface of the brain; they often originate in the dura mater, and when exposed are easily enucleated. Improvement in the symptoms may follow the administration of iodides and mercury, or organic arsenical salts of the salvarsan group, but in many cases the growth is very resistant to anti-syphilitic treatment.

Tuberculous masses occur most frequently in children and adolescents, and other signs of tuberculosis are usually present. The cerebellum is a common seat of these tumours, and they are often multiple. Their growth may be rapid at first, and then become arrested for a time. Spasmodic growth of a tumour strongly suggests its tuberculous nature, and superadded signs of basal meningitis confirm the diagnosis.

Endothelioma grows from the dura mater, and in so far as it is a well-defined and non-infiltrating growth it lends itself to removal by operation. Unfortunately, however, it is usually located at the base of the brain and is not readily accessible.

Glioma is usually met with in the young; it tends to grow slowly at first, but may take on a rapid growth at any time, and haemorrhage is liable to occur into the substance of the tumour, causing a sudden aggravation of the symptoms.

Sarcoma occurs between puberty and middle life; it grows slowly, and compresses rather than destroys the brain tissue. It is sharply defined from the surrounding cerebral tissue, and is therefore more favourable for operation than glioma.

The prognosis is grave in all forms of brain tumour. Even in syphilitic growths, although the more urgent symptoms may be ameliorated by the use of drugs, recurrence is liable to occur, and the structural changes induced in the cerebral tissue, and the contraction of the cicatrix which results, may permanently interfere with the functions of the brain, or may induce Jacksonian epilepsy. Tuberculous tumours also may become arrested, and may cease for a time to cause symptoms, but permanent cure is extremely rare. We have known a sarcoma to recur as late as five years after removal. Death sometimes occurs suddenly from haemorrhage, from acute oedema, or from implication of vital centres.

Treatment.—It is to be borne in mind that gummatous growths in the brain are seldom influenced to any extent by anti-syphilitic remedies, and time should not be wasted in trying this form of treatment.

The question of removal by operation arises in cases in which there is reason to believe that the tumour is situated near the surface of the brain and that it is circumscribed and of moderate size. Unfortunately it is only in a small proportion of cases that these conditions are present and can be recognised before opening the skull.

In many cases in which there is no hope of being able to remove the tumour, it is advisable to relieve symptoms due to excessive intra-cranial tension, such as blindness, severe headache, and persistent vomiting, by performing a "decompression operation" (Operative Surgery, p. 108). The relief that follows such operations is often remarkable.

Lumbar puncture, frequently repeated, has also been practised for the relief of tension in inoperable cases, but it is not free of danger and is not to be looked upon as a substitute for a decompression operation.

When surgical treatment is contra-indicated, all that can be done is to palliate the symptoms by bromides, opium, phenacetin, caffein, and other drugs.

Tumours of the Pituitary Body or Hypophysis Cerebri.—The tumours most frequently met with in the pituitary body are of the nature of adenoma with hyperplasia and cystic degeneration; carcinoma and sarcoma also occur. They develop slowly and give rise to comparatively slight increase in the intra-cranial tension. When the anterior lobe is implicated and there is a pathological increase in the functional activity of the gland (hyperpituitarism), signs of acromegaly may ensue. Diminution of function (hypopituitarism) is attended with infantilism, a rapid deposition of fat in the subcutaneous tissue, and a decrease or loss of the genital functions. In women, amenorrhoea is an early and constant symptom. Intense drowsiness is a marked feature in some cases.

From their position close to the back of the optic chiasma these growths affect the fibres passing to the nasal half of each retina, and so give rise to bilateral temporal hemianopsia, and although there is no choked disc, the optic nerves undergo primary atrophy from pressure, and there is failure of sight.

Marked temporary benefit has followed the administration of thyreoid extract. Operative treatment has been successful in a number of cases, but as the anterior lobe is essential to life, the operation is merely directed towards the relief of pressure on the optic chiasma with a view to preventing loss of vision. We have seen marked relief follow a temporal decompression operation.

Epilepsy.—The surgical aspects of Jacksonian epilepsy following head injuries have already been considered (p. 358). For the cure of those forms of epilepsy in which there is no gross lesion of the brain, numerous surgical procedures have been suggested, but from none of these have the results been encouraging.

Hernia Cerebri.—This term is applied to a protrusion of brain substance through an acquired opening in the skull and dura mater, such as may result from a compound fracture or a gun-shot wound. The protrusion is due to increased intra-cranial tension, and is almost invariably associated with infection of the brain and its membranes, and with the presence of a foreign body or fragments of bone. Other things being equal, a hernia is more likely to occur through a small than through a large opening in the skull.

So long as the extruded portion of brain matter is small, it pulsates, but as it increases in size and is pressed upon by the edges of the opening through which it escapes, the pulsation ceases, and the herniated portion may become strangulated and undergo necrosis.

In cases of compound fracture, and in other conditions associated with necrosis of bone, masses of redundant granulation tissue growing from the soft parts outside the skull may simulate a hernia cerebri.

The treatment consists in counteracting the septic infection by purifying the protruding mass, and if necessary by enlarging the opening in the skull with rongeur forceps to admit of the removal of foreign bodies or bone fragments and to relieve the inter-cranial tension. Steps must also be taken to prevent meningitis, which, if it occurs, is usually fatal. Pressure over the hernia, with the object of returning it to the skull, is to be avoided, and the herniated portion should not be cut away unless it is sloughing, or has become pedunculated. It may be got rid of by painting it with 40 per cent. formalin, which causes a dry, horny crust to form on the surface; this is picked off, and the formalin re-applied.

After the hernia has disappeared and the wound is aseptic, steps should be taken to close the gap in the skull. This may be done by an osteo-plastic operation in which a flap, comprising a segment of the outer table, is raised from an adjacent part of the skull and placed in the gap; or by transplanting a portion of periosteum-covered bone from the scapula, tibia, or other suitable source. An alternative method is to implant a plate of celluloid, silver or other metal, or a portion of the fascia lata, in the gap. When a permanent hole is left in the bone, the patient should wear over it a leather or metal shield to protect the brain.

The protrusion of brain resulting after a decompression operation deliberately performed for the relief of intra-cranial tension, unless it becomes infected, has nothing in common with a hernia cerebri.

SURGICAL AFFECTIONS OF THE CRANIAL NERVE

Irritation, or paralysis, of one or more of the cranial nerves may result from lesions implicating their centres or trunks.

When the trunk of the nerve is affected, the paralysis is on the same side as the lesion, and is of the lower neurone type; when the cortical centre or the upper axons are involved, it is on the opposite side, and is of the upper neurone type (p. 334). The lesions of the cerebral centres with which nerve symptoms are most frequently associated are: laceration of the brain, haemorrhage, meningitis, tumour, and syphilitic gumma.

The nerve-trunks may be contused or torn across, especially in basal fractures which traverse their foramina of exit; blood may be effused into their sheaths as a result of injuries not attended with fracture; or they may be pressed upon by an inflammatory effusion, a tumour, a gumma, or an aneurysm invading the base of the skull. When the nerve is merely contused, or pressed upon by blood-clot, the paralysis tends to pass off in the course of a few days. When it is torn across, or compressed by a new growth, the paralysis is permanent. In some traumatic cases paralysis does not come on until a few days after the injury, and is then due either to gradually increasing pressure from blood-clot, or more probably to the onset of meningitis or of ascending neuritis.

I. The branches of the Olfactory Nerve may be ruptured as they pass through the cribriform plate in fractures implicating the anterior fossa of the skull, and there results complete and permanent loss of smell (anosmia). Haemorrhage into the nerve sheath or contusion of the nerve may cause a transitory loss of smell. The trunk of the nerve may be implicated also in tumours and meningitis in the anterior fossa. In all cases in which anosmia results there is also interference with the power of recognising different flavours, thus greatly impairing the sense of taste.

II. Optic Nerve.—Temporary paralysis of one or both optic nerves is a comparatively common result of traumatic effusion of blood into their sheaths; the resulting blindness may pass off in a few days, or may last for some weeks. When a large effusion takes place, the prolonged pressure on the nerve may result in optic atrophy and permanent blindness. Complete severance of the nerve by a bullet, the point of a sharp instrument, or a fragment of bone, results in loss of sight in the eye on the same side. In cellulitis of the orbit, intra-orbital tumour, gumma and aneurysm in the region of the cavernous sinus, also, the optic nerve may be implicated.

Lesions implicating the cortical centre for sight in the occipital lobe give rise to hemianopia—that is, loss of sight in the lateral halves of the fields of vision of both eyes—colour-blindness, subjective sensations of light and colour, and other eye symptoms.

Double optic neuritis, followed by optic atrophy, is one of the most constant effects of the growth of a tumour within the skull, and is not uncommon in cases of cerebral abscess and meningitis. Pressure on the optic chiasma, for example by a tumour of the pituitary body, is associated with bilateral temporal hemianopsia.

III. Oculo-Motor Nerve.—One or more of the branches of this nerve may be compressed by extravasated blood, or be contused and lacerated in fractures implicating the region of the sphenoidal fissure. Fixed dilatation of one pupil may result from pressure by blood-clot, without other functional disturbance of the nerve. A tumour or an aneurysm growing in this region also may press upon the nerve. Sometimes both nerves are involved—for example, in fracture implicating both sides of the anterior fossa, and in tumours, particularly gumma, growing in the region of the floor of the third ventricle. In lesions of the cerebral hemispheres the third nerve is frequently paralysed. Its cortical centre lies in close proximity to the centre for the face (Fig. 179).

The most prominent symptoms of complete paralysis are ptosis or drooping of the upper eyelid, lateral strabismus, and slight downward rotation of the eye with diplopia. There are also dilatation of the pupil from paralysis of the circular fibres of the iris, and loss of accommodation and reaction to light from paralysis of the ciliary muscle.

Paralysis of the muscle supplied by the third nerve is frequently associated with paralysis of other ocular muscles. When all the muscles of the eye are paralysed, the condition is known as "opthalmoplegia externa"; it is usually due to syphilitic disease in the floor of the third ventricle.

IV. The Trochlear or Patheticus Nerve, which supplies the superior oblique muscle, may suffer in the same way as the oculo-motor nerve. When it is paralysed, there is defective movement of the eye downward and medially, and the patient may complain of diplopia when he looks downward.

V. Trigeminal Nerve.—The most important surgical affection of this nerve is "trigeminal neuralgia," which has already been described (Volume I., p. 373). One or other of the divisions of the nerve may be torn in fractures of the base of the skull, and there results anaesthesia in the area supplied by it. In fractures crossing the apex of the petrous portion of the temporal bone, the great and small superficial petrosal nerves may be ruptured, and the soft palate and uvula are paralysed and there is difficulty in swallowing; there are also painful sensations in the ear. When the ophthalmic division is implicated, the conjunctiva is rendered insensitive, and conjunctivitis, which may be followed by ulceration of the cornea, results from exposure to dust and other foreign bodies, which, on account of the anaesthetic condition of the eye, are allowed to remain and cause irritation.

VI. Abducens Nerve.—This nerve, which supplies the lateral rectus muscle, has the longest course within the skull of any of the cranial nerves. In spite of this fact, it is comparatively seldom torn in basal fractures; but it is prone to be pressed upon by tumours, gummas, or aneurysms in the region of the base of the brain. When it is paralysed, medial strabismus results.

VII. Facial Nerve.—Paralysis of the facial muscles, more or less complete, is the most characteristic symptom of lesions of this nerve.

Paralysis of the Cerebral Type.—When the fibres of the nerve are implicated in any part of their course between the cortical centre and the nucleus in the lower part of the pons, the paralysis is of the upper neurone (cerebral) type. It affects the side of the face opposite to that of the lesion, and the defective movement is more marked in the lower than in the upper half of the face.

This form of facial paralysis may be due to the pressure of an intra-cranial tumour, abscess, or haemorrhage, or to degenerative processes in the cerebral tissue, and as a rule other cranial nerves are also affected. Its recognition is chiefly of diagnostic and localising importance.

Paralysis of the Peripheral Type.—When the trunk of the nerve is implicated between the pontine nucleus and its peripheral distribution, the paralysis is of the lower neurone (peripheral) type, the muscles on the same side as the lesion being flaccid and atrophied.

The majority of cases are of the so-called "rheumatic" variety, and are attributed to exposure to cold. Others result from fractures implicating the middle fossa of the skull, or are associated with chronic suppuration in the middle ear.

In fractures passing across the petrous temporal, the nerve may be torn at the time of the injury, or may become pressed upon by a traumatic effusion or by callus later, but considering the frequency of these fractures it is comparatively seldom damaged.

Suppurative disease of the middle ear is a more common cause of facial paralysis. The nerve, as it traverses the facial canal (aqueductus Fallopii), may be pressed upon by inflammatory effusions or granulations, or may be destroyed by the suppurative process, particularly in young children, as in them the osseous wall of the aqueduct is very thin. It may also be involved in tuberculous and in malignant disease of the middle ear.

The nerve may be injured also in the course of operations on the mastoid or middle ear, or in the removal of tumours or glands in the parotid region. As the nerve breaks up into numerous branches soon after it leaves the stylo-mastoid foramen, the paralysis may be confined to one or more of its branches.

Temporary paralysis may result from inflammatory conditions such as parotitis, or from blows or pressure over the nerve, for example by the forceps in delivery.

Symptoms.—In complete unilateral facial paralysis (Bell's paralysis) the affected side of the face is expressionless and devoid of voluntary or emotional movement. The muscles are flaccid, the cheek is flattened and smooth, all its folds and wrinkles being obliterated. When the patient speaks or smiles, the face is drawn to the sound side (Fig. 201). The eye on the affected side cannot be closed, and on making the attempt the eyeball rolls upwards and outwards. The lower lid droops, the patient cannot wink, and the conjunctiva therefore becomes dry, and is irritated by exposure to cold and dust. The tears run over the cheek. From paralysis of the buccinator muscle there is inability to whistle or to puff out the cheeks and food collects between the cheek and the gums. The orbicularis oris being also paralysed, the patient is unable to show his upper teeth, and the labial consonants are pronounced indistinctly. The sense of taste is often impaired from involvement of the chorda tympani nerve.