Chapter XXXII

. _Acute periostitis_ is, in the main, due either to syphilis or to an infection following injury. In the latter case it proceeds from the margin of the wound, and may spread to a considerable distance. It is in some instances secondary to deeper infection extending from the middle ear, and then is found posteriorly to the ear and externally to the mastoid cells. Congenital openings or defects of the sutures about the mastoid seem to have much to do with the travelling of infectious lesions in these localities.

[Illustration: FIG. 369

Osteoma of skull. (Mudd.)]

[Illustration: FIG. 370

Same as Fig. 369, seen from below.]

=Acromegaly and Leontiasis= have been considered on pages 437 and 438.

=Acute Osteomyelitis.=--Acute osteomyelitis is due to essentially the same causes as those just discussed. In this case it is especially in the diploë that the principal ravages occur. Unless promptly recognized and relieved by surgical measures this is likely to lead to sepsis of the pyemic type and at a relatively early period, the venous arrangement of the diploë favoring such type of disease.

=Necrosis of the Skull.=--Necrosis of the skull is ordinarily the result, directly or indirectly, of injury, in which case it is usually of the acute form, a fragment, which has been too much separated from its surroundings to live, giving evidence of early and easily recognizable death. This necrosis is mainly confined to the external table. Necrosis of slow origin is due either to tuberculosis or syphilis, perhaps more often to the latter. Under a cold abscess of the scalp or subperiosteal abscess will often be found a small area of dead external table which needs complete removal. Necrosis has also been observed to follow severe burns of the scalp. It is usually combined with caries of adjoining bone. The caries produced by syphilis is illustrated in Fig. 371.

[Illustration: FIG. 371

Syphilitic caries of cranium. (Bruns.)]

INJURIES TO THE HEAD PREVIOUS TO AND DURING BIRTH.

_In utero_ the head is surrounded by amniotic fluid and is well guarded against injury. Nevertheless as the result of penetrating wounds or of falls on the part of the mother real injuries do occasionally occur. Most of the cases of skull fracture reported as occurring before birth have occurred during delivery. _Multiple fractures_ of the skull of either character have been observed.

During the process of parturition there nearly always appears a tumor of the scalp in the newborn, known as the _caput succedaneum_, at the point where pressure upon the head has been least. It usually disappears quickly after birth. It is due to a collection of blood,

## partly an extravasation, as the result of compression or injury. It is

composed also of edematous soft tissues of the surface. If incised, blood-stained serum is poured out. When this fails to rapidly resorb during the first days of the infant’s existence, and especially if it fluctuate, it may be incised under antiseptic precautions and blood clot be turned out. In rare cases it suppurates, by which is produced an acute abscess, which should be promptly evacuated.

A collection of fluid blood between the periosteum and the bone is known as the _cephalhematoma neonatorum_, such a lesion occurring on an average once in two hundred cases. It is generally found over the fissures, and appears to be produced by the sliding of the bones. This collection also usually promptly disappears. In case of failure it may be aspirated or incised. Before resorting to any operative procedure it would be well to make a careful distinction between a possible meningocele or encephalocele, as a congenital defect, and cephalhematoma as an accident of delivery.

[Illustration: FIG. 372

Fracture of right frontal bone in a newborn infant; fracture extending into orbit. (Bruns.)]

A depression in the skull of a newborn child which does not quickly right itself or yield to expanding influences from within should not be allowed to go uncorrected, as serious lesions ordinarily of paralytic type may result therefrom. In these days of aseptic surgery there is no reason why such operation as may be necessary to elevate a fragment or an entire bone should not be performed, with the usual precautions.

IMPORTANT POINTS IN THE SURGICAL ANATOMY OF THE SKULL.

The young and the aged have no distinction of tables of the skull, but the diploë which separates the two tables is an affair of middle age, develops slowly, and disappears after the same fashion--sometimes to such an extent as to leave the skull of almost paper-like thinness. In all operations, then, upon the young and the old the surgeon should proceed with extreme caution, as if expecting to find the skull quite thin. The lower limit of the squamous bone proper is the so-called mastosquamosal suture, and operations confined to the squamous plate alone are safe from injuring the sigmoid sinus on its inner side. The ridge at the posterior root of the zygoma indicates, by its lower border, the level of the mastoid antrum. A few lines above this is the level of the base of the brain. The _mastoid_ is present at birth and appears externally by the second year. Its _antrum_ is present also at birth, though its air cells do not develop until after puberty, their location being previously occupied by cancellous tissue. Most of these cells open into the antrum, a few directly into the tympanum. They are not always separated from the sigmoid sinus by bone. The

## partition between them is perforated by minute veins, forming an easy

communication between the sinus and the antrum. Air escaping from the mastoid cells into the overlying tissue may cause emphysema from a basal fracture. In all operations upon the mastoid antrum the operator should keep to its outer side, and the higher and the more closely to the posterior zygomatic ridge he makes the first opening the more sure is he to escape injuring the facial nerve. The _groove for the sigmoid sinus_ extends to the jugular foramen from a point on the outside corresponding to the asterion. The _lateral sinus_ may be indicated externally by a line from the superior border of the mastoid to the inion--_i. e._, from the asterion to the inion.

The _frontal sinuses_ are usually separated by a septum, which is often incomplete or wanting. They are variable in size and outline, and do not develop until after the seventh year. The _infundibulum_, by which they empty into the nasal cavity, is often so small that when the lining membrane is involved it becomes closed, and retention, with its accompanying symptoms--pain, tenderness, swelling, etc.--may ensue. Ulceration and erosion, however, may cause perforation internally through the supra-orbital plates, so that pus may penetrate through the inner half of the orbit.

Aside from its direct communication the superior longitudinal sinus connects with the basal sinuses through the middle cerebral and the Sylvian veins, while communications with the middle meningeal veins are abundant. Where the frontal and diploëtic veins enter the longitudinal sinus there frequently are dilatations in which marasmic thromboses often originate. This sinus is also connected with the veins of the nasal septum, so that a septic phlebitis may be propagated from the nose. So much of the lateral sinus as is contained in the sigmoid groove is known as the _sigmoid sinus_, which connects directly with the exterior through the mastoid and the posterior condyloid veins. In sinus thrombosis this mastoid vein is likewise affected. One or more condyloid veins accompany the hypoglossal nerve through the anterior condyloid foramen, and may also serve for the propagation of infection or exit of pus.

While septic particles may be carried from any part of the lateral or sigmoid sinuses--usually through the internal jugular--they may also be carried by way of the other veins above mentioned or the occipital sinus, all of which empty directly into the subclavian without passing through the internal jugular. These sinuses are all rigid tubes, always open, while the veins are thin and flexible, their caliber constantly varying with inspiration and expiration. The sinuses contain no valves, and these are very rare in the cerebral veins.

So far as the _lymphatics_ are concerned there is free and easy communication between the internal and external plexuses and nodes. Into the superficial nodes, along the external jugular, outside of the deep fascia, empty all the external lymphatics of the head. Intracranial infection shows itself in swelling of the deep cervicals beneath the deep fascia. Lymphatics are abundant in the dura, and pathogenic organisms, once housed within the dura, find it easily open to invasion. The potential interval between the dura and the arachnoid is termed the _subdural space_, when considerable effusion may occur without marked symptoms, owing to its easy diffusion, while blood here poured out may travel even to the lowest parts of the spine and cause death by pressure upon remote points.

The _arachnoid_ bridges over the convolutions and does not extend into the sulci. It is not vascular; at certain points it is adherent to the pia, at others it does not touch it. The _subarachnoid space_ is formed in the latter way, and within it most of the cerebrospinal fluid is contained. This space is unevenly distributed over the brain surface, most prominently beneath the posterior two-thirds of the brain, where there is a wide interval between the arachnoid and the pia, extending forward around the medulla and pons and as far forward as the optic nerves. This space connects with the ventricles by the foramen of Magendie, as well as with the sheaths of the cranial nerves. Where these nerves escape from the brain or cord they are covered by all three membranes, the layers being most distinct along the optic nerves. Fluid injected into the subdural space may pass along the spinal nerves as far as the limbs. It is essential to realize this in order to appreciate how extensive is the surface exposed in leptomeningitis.

Internal hydrocephalus is often the result of closure of the foramen of Magendie. The cerebrospinal fluid is rapidly reproduced after traumatic escape. External hydrocephalus or accumulation in the subarachnoid space, is a condition frequently due to tuberculous infection.

The _pia_ is the vascular coat of the brain, supplied with an extensive network of fine nerve fibers derived from the sympathetic and the cranial nerves, having intimate relations with the brain, to such an extent that leptomeningitis and encephalitis are almost inseparable. The nerve supply to the cerebral membranes explains the severe pain of meningitis.

INJURIES TO THE SOFT PARTS OF THE CRANIUM.

In direct connection with what has been stated above it is well to emphasize that the venous communications between the exterior and interior of the cranium are numerous, and that the frequency of these anastomoses explains the ease with which extracranial infections are propagated within; in other words, these explain the frequency of septic mischief in the brain after external injuries.

=Penetrating and Incised Wounds.=--Penetrating and incised wounds are frequent about the head, their prognosis _per se_, as well as their proper treatment, varying but little from that of such wounds in other parts, so long as the skull proper and its contents escape injury. Hemorrhage from scalp wounds may be profuse and even fatal. The most dangerous hemorrhages occur from the temporal vessels. Penetrating wounds are short, and the periosteum and underlying bone are usually also injured. Such small articles as blades of penknives, particles of dirt, etc., will often be found when the parts are carefully inspected, a measure never to be neglected. Contusions of the scalp and skull are spoken of as subcutaneous, subaponeurotic, or subperiosteal, and are most frequent in the frontal and lateral regions. Ecchymoses following them may be extensive and discoloration may spread over a large area. In traumatic hematomas resulting from various injuries incision should be an early resort should blood clot fail to resorb.

INJURIES TO THE CRANIAL BONES.

All conceivable degrees of injury to the bones, from a trifling division of the periosteum down to most extensive denudation or mangling of the external table or the entire thickness of the bones, may be encountered. These lesions may be spread over a large area or may be the result of penetrating wounds. In other words, we may have linear, penetrating, or large surface wounds, with such injury to the scalp as perhaps to amount to a total loss of covering for the same. All of these, moreover, may be complicated by fractures of the bone at the point of injury, with or without brain lesions, or by other and more remote lesions.

In regard to most of these, it may be said that _non-penetrating injuries_, when promptly and properly attended to, have, in most cases, a favorable prognosis. Every _penetrating wound_ of the cranium is a condition justifying grave prognosis, on account of the great danger of infection incurred. Other features of these wounds, with more in regard to prognosis and treatment, will be given under the head of Compound Fractures of the Skull, etc.

It is necessary, however, to say in this place that penetrating wounds of the cranium are often received in a way which does not permit actual diagnosis, as, for instance, when received through the nose or the orbit. Every wound whose history and appearance indicate that penetration may have occurred should be subjected to the most rigid scrutiny and care. Points of fencing foils, umbrella tips, etc., have been forced into the brain cavity through the orbit and elsewhere in ways which left little external evidence of the severity of the injury.

FRACTURES OF THE SKULL.

Following the anatomists, and for general convenience, these are divided into _fractures of the vertex_, of the _lateral region_, and of the _base_, the former being the most frequent as the vertex is the most exposed. A fracture in a given region may be confined to that locality or may radiate widely or extend nearly around the cranium. Of all the fractures of the bony skeleton those of the skull constitute about 2 per cent.

Fractures of the Vertex of the Skull.

Fractures of the vertex are, in most instances, due to actual violence, the force being often expended at the point of application or producing radiating fractures. Those which are limited to the neighborhood of the injury are referred to as _direct_ fractures, in distinction to which we have _indirect_ or _radiating_, often producing remarkable results. Fractures may vary between the simplest crack or fissure, accompanied by but trifling brain symptoms and never recognized, to the most extensive comminution and destruction of cranial bones which can be imagined.

=Splintered or Comminuted Fractures.=--Splintered or comminuted fractures refer to the formation of numerous bony fragments, which are often more or less loosened, sometimes completely so, occasionally dovetailed together, and often driven in or depressed. Such fractures are direct. It is possible to have comminution without depression; the latter makes it the more grave condition.

Fractures with absolute loss of substance may be made by gunshot injuries or by any extensive splintering or by a penetrating body. It is possible to have _fracture of one table without that of the other_, this being often true of the external table. In isolated fractures of the inner table there is often dislodgement of small fragments which may injure the dura and possibly produce later epileptic or irritative disturbance. When the external table is chipped off the diploë is exposed, and this with its wonderfully fine venous communications opens up a wide area to infection and subsequent pyemia.

=Gunshot Fractures.=--Gunshot fractures are always depressed and almost invariably comminuted. The bullet of the modern army rifle possesses a great initial velocity, and the cranium struck by it will probably be disrupted into fragments, causing instant death. The majority of gunshot fractures of the skull seen in ordinary civil practice are due to revolver or pistol bullets from weapons of the prevailing type. In these instances there will usually be penetration, perhaps with perforation of the skull, and the formation thus of one or of two compound fractures, the wound of entrance being always comminuted and depressed, while fragments of bone may be scattered along the course of the bullet, which may also carry infectious material from without, such as hair, particles of hat, and the like (Figs. 373 and 374). (See also Figs. 52, 53 and 54.)

[Illustration: FIG. 373

FIG. 374

Gunshot fracture of skull. (Helferich.)]

Whatever may be the wisdom of operating in other cases where there is room for doubt as to the proper course there rarely is uncertainty as to the proper treatment of gunshot wounds of the skull, which _should be invariably subjected to operation_.

It will thus be seen that fractures of the skull may be _simple_ or _compound_, or _complicated_ with other injuries, or _depressed_, without any reference to whether they are simple fissures or more extensive injuries. On the other hand, depressed and comminuted fractures may occur without being compound in a surgical sense, and with each one of these injuries there may be accompanying disturbance of the brain of any degree of severity, from the mildest concussion or shock up to rapidly fatal compression. Any imaginable complication of these head injuries is not beyond the bounds of possibility.

The essential features in explaining the _mechanism of fractures_ of the vertex are the area involved and the violence of the impact. The skull is often surprisingly elastic, even in the oldest individuals, and fractures occur ordinarily when the natural limits of elasticity have been exceeded and bone cohesion overcome. Children particularly suffer from depression without fracture, which formerly was never operated upon, but which is now regarded as requiring operation. On the other hand, certain skulls are _abnormally fragile_ (see Fragility of the Bones,