time of the injury may have a determining effect on the lesions that occur. According to Bouchard, if a blow is received during inspiration, when the brain is more or less completely surrounded by cerebro-spinal fluid, the condition of concussion is produced, whereas if it is received during expiration, when there is less cerebro-spinal fluid in the cranial cavity, the protection of the water-bed is diminished and the more serious condition of contusion results.

SYMPTOMS.-The symptoms resulting from this disturbance of the brain vary from drowsiness to complete unconsciousness. The respiration becomes shallow and feeble, and the pulse is small, not easily felt, and often unduly slow. After a period varying from a few minutes to some hours the pulse improves, the respirations become deeper, the reflexes return, and the patient begins to recover. During recovery, the patient generally vomits and may wander a little. He may also complain of noises in the head or disturbances of vision. In severe cases there is complete prostration; the surface of the body is cold, the breathing is shallow and quick, the pulse very feeble, and there is frequent vomiting; recovery is often accompanied by symptoms of cerebral irritation.

TREATMENT.-Measures must be adopted to diminish the shock, while care is taken to avoid too much reaction lest hæmorrhage should occur. The patient should be placed in the recumbent position, and the head raised on a small pillow so as to diminish the risk of hæmorrhage. Warmth should be applied to the feet and limbs by means of hot blankets and hot-water bottles. Strychnine (gr. g) or camphor may be administered subcutaneously, but alcoholic stimulants or the administration of ether should be avoided, except in desperate cases, on account of the great risk of increasing the reaction. The patient should be placed in a room free from noise, and a brisk purge should be administered; if he is still unconscious five grains of calomel, or one or two drops of croton oil mixed with powdered sugar, may be placed on the back of the tongue. In some cases of concussion there is retention of urine, especially during the stage of recovery, and, if necessary, the urine must be drawn off with a soft catheter. Most cases of concussion will recover under this treatment or even without any special treatment at all.

When reaction commences, it is well to apply cold to the head with the view of preventing hæmorrhage. The patient should be kept in a dark room and not allowed to see visitors or to talk, and an ice-bag, ice-cap, or Leiter's tubes (see Vol. I. p. 8) should be applied to the head. Even if the patient apparently recovers completely, there is no certainty that hæmorrhage will not take place, and to minimise this risk he should be kept in bed for a week at least, especially when the concussion has been severe. During this time quiet should be maintained, the bowels kept freely open by the daily administration of a saline purge, and the diet considerably restricted. As a rule the patient may be allowed to get up

at the end of a week, but the possibility of after-consequences (especially mental irritability) must always be borne in mind. A mechanic may be able to resume work at the end of a few weeks, provided that his employment does not entail climbing ladders, or working at a height; these are dangerous on account of the liability of these patients to suffer from attacks of giddiness. Such a patient would, therefore, be well advised to seek less dangerous employment for a few months, but after that time, if he has had no attacks of giddiness, he may be allowed to resume his former employment. In the case of patients whose work entails intellectual effort, the disability is often more pronounced, and the patient, although he feels quite well, may be unable to add up a column of figures accurately or without getting a headache, or to act in an emergency with his former judgment and decision. This applies also to engine-drivers, chauffeurs, and others, from whom rapid and almost automatic decisions are constantly demanded; such patients should lead a quiet life for six to nine months. There is no need to confine them to bed or even to the house. Mild out-of-door exercise may be permitted, and they may undertake light work which does not involve any severe mental strain. The diet should be light and nutritious, but alcohol should only be allowed in the very strictest moderation, and it is better to forbid it altogether. Smoking, on the other hand, may be permitted.

CONTUSION AND LACERATION OF THE BRAIN.

In some cases the laceration of the brain, of which we have spoken in connection with concussion, is very marked, and this may occur with or without fracture of the skull itself. The injury to the brain may be situated immediately beneath the seat of the blow, or on the opposite side of the skull ('contre coup'), and may vary from a small tear to an extensive laceration of the cortex. These lacerations are most frequent about the convexity of the hemispheres, but they are also met with at the base, when the brain has been violently jarred against the bony prominences on the floor of the cranial cavity.

The symptoms peculiar to severe lacerations of the brain are chiefly those of cerebral irritation. The patient, after recovering from the primary shock or concussion, exhibits abnormal irritability of temper, muscular twitchings, irregular movements, and extreme restlessness; the occurrence of these symptoms soon after an accident should lead to the conclusion that the brain matter has been damaged.

TREATMENT.-The treatment of this condition is the same as that just described for concussion, but especial care must be taken in the early stage to avoid excessive reaction and to diminish the risk of hæmorrhage into the brain. For some time the patient should be kept quite free from all disturbing influences, and in a good many cases the irritable condition gradually passes off and the patient recovers completely.

III.

BB

Cushing recommends that a sub-temporal decompression operation (see p. 438) should be performed in the majority of these cases. He claims that by this procedure the risks of after-complications are minimised, and that it is possible, by exploring the brain, to determine more accurately the extent of the injury, and to adopt appropriate measures for its treatment. This view has not yet received general acceptance, but the suggestion should be borne in mind.

COMPRESSION OF THE BRAIN.

After the symptoms of concussion have passed off, the patient may either remain well or he may again lapse into unconsciousness, from which it may be impossible to arouse him. This unconsciousness is due to compression of the brain, which may arise from various causes. When there has been no recovery from the concussion the compression may be due to a depressed fracture (see p. 341), usually complicated with intracranial hæmorrhage. When the symptoms of compression come on a few hours after the injury, they are probably due to intra-cranial hæmorrhage alone; if they supervene at a later period, they are usually the result of cerebral inflammation and suppuration.

The general symptoms of compression of the brain are profound loss of consciousness, stertorous breathing, and slow pulse. The pupils are usually dilated and fixed; in cases due to rupture of the middle meningeal artery the pupil on the side of the lesion is generally larger than its fellow. If the pressure is not relieved, the patient may remain unconscious for some hours and then die from gradual heart failure.

INTRA-CRANIAL HÆMORRHAGE.

Hæmorrhage occurring inside the skull may be either extra-dural or sub-dural; sub-dural hæmorrhage again may be beneath the dura mater, or into the pia mater, or into the substance of the brain. When the hæmorrhage occurs rapidly after an in ury and in such amount as to give rise to marked compression after a lucid interval, it is probably extra-dural and most frequently results from rupture of the middle meningeal artery or one of its branches. In other cases it may be due to rupture of one of the vessels of the pia mater, or again there may be rupture of one of the large venous sinuses in the brain; here the symptoms are more gradual in onset, partly because the bleeding is slower and also partly because this condition is usually associated with fracture, and some of the blood may therefore escape externally.

Lumbar puncture is often of great diagnostic value in these cases. If the hæmorrhage is entirely extra-dural there will be no alteration in the cerebro-spinal fluid; in intra-dural hæmorrhage, on the other hand, the fluid will contain blood (see p. 444).

RUPTURE OF THE MIDDLE MENINGEAL.-This artery is the largest branch of the internal maxillary trunk and enters the skull through the foramen spinosum, running upwards in a groove on the greater wing of the sphenoid. About one centimètre above. the foramen it divides into an anterior and a posterior branch, of which the anterior is the larger, and runs in a groove across the greater wing of the sphenoid and thence across the anterior inferior angle of the parietal bone. It then passes upwards almost parallel to the anterior border of that bone and sends branches forwards and backwards over the frontal and parietal bones. The posterior branch passes backwards over the squamous portion of the temporal bone and turns upwards near the posterior inferior angle of the parietal running just in front of the posterior border of that bone. It reaches as far as the middle line and its branches run as far back as the lateral sinus. Throughout their whole extent both branches of the artery lie in grooves in the bone, converted into channels by the dura mater, and are much more adherent to the latter than to the bone. The anterior branch is the one usually torn. The main branches of this vessel are in close relationship with various motor areas of the cortex, and thus hæmorrhage from them may cause direct pressure upon these areas and give rise to paralysis of various parts, according to the seat of the rupture and the extent of the hæmorrhage.

The following are the chief surface markings of the artery: The anterior branch passes beneath a point situated an inch and a half behind the external angular process of the frontal bone and the same distance above the zygoma. The posterior branch crosses the posterior inferior angle of the parietal bone beneath the point of intersection of a line drawn from the glabella backwards to the external occipital protuberance, with another drawn vertically upwards from the posterior margin of the mastoid process (see Fig. 156).

Rupture of the middle meningeal artery generally occurs in connection with a fracture, the line of which traverses the groove in which the artery lies (see Fig. 154) or crosses the foramen spinosum itself. Rupture of the artery, however, may take place without any fracture, the probable explanation being, that the alteration in the shape of the skull produced by the blow is insufficient to fracture the skull, but enough to detach the vessel from its groove in the bone and tear it across. Hæmorrhage without fracture occurs most commonly in adults, probably because in children the dura mater is more closely adherent to the bone and, therefore, less easily separated from it when the skull is compressed.

The blood from the torn vessel is poured out between the dura mater and the skull, and rapidly detaches the former from the bone. This blood

1 The glabella is the smooth space directly above the root of the nose, midway between the two superciliary ridges.

soon clots, and pressure is exercised upon the subjacent brain, varying according to the amount of the clot. When the amount of clot is small, the effects of the pressure are manifested in one hemisphere only, and may possibly be confined to particular centres. As the clot increases in size, however, the entire hemisphere shows the effects of pressure, and in

FIG. 154.-MIDDLE MENINGEAL HEMORRHAGE. The fracture is seen to traverse both the vault and the base of the skull. The situation of the clot is that usually met with. The amount of clot present in the specimen from which the drawing was made is quite moderate; it often exceeds this considerably and gives rise to very extensive cerebral compression. (Helferich.)

extensive hæmorrhages the opposite hemisphere is affected as well. As a rule the tendency is for the blood to spread downwards towards the base of the skull, and one of the typical symptoms, namely, dilatation of the pupil on the affected side, is probably due to clot passing downwards and pressing upon the third nerve. Should the rupture of the artery be accompanied by fracture of the skull, some of the blood escapes beneath