The Surgery of the Skull and Brain

by Louis Bathe Rawling

Hæmorrhage into the subdural space may be (a) diffuse, or (b) localized.

(A) Diffuse subdural hæmorrhage.

The blood may be derived from one of the great sinuses of the brain or from superficial cerebral vessels (laceration of the brain).

The superior longitudinal sinus may be torn by the in-driving of fragments of bone in a comminuted depressed fracture of the vertex, or by wide separation along the line of the sagittal suture. Blood is diffused throughout the subdural space, on one or on both sides of the falx cerebri, but always tending to gravitate towards the lower limits of the supra-tentorial space.

In the event of the wound being compound, air may enter into the sinus. Insomuch, however, as the sinus pressure is, under normal conditions, positive, this complication is of rare occurrence, unless the patient is in a state of profound shock, from loss of blood, or suffers from urgent dyspnœa.

Allusion should also be made to the condition described by Stromeyer, as ‘sinus pericranii’, where a subpericranial hæmatoma communicates with a venous sinus. Such hæmatomata may pulsate, are more or less reducible on pressure, and are increased on straining or on the application of pressure to the internal jugular vein.

The lateral sinus may be laid open in any part of its course, more especially at the angle of junction between the lateral and sigmoid sinuses, in close relation to the occipito-mastoid suture, a region not infrequently involved in basic fractures. The blood effused will occupy the supra- or infra-tentorial spaces according to the situation of the rent in the sinus-wall.

The cavernous sinus is frequently involved in anterior and middle fossa fractures. The blood effused usually escapes into the nose and mouth.

Fig. 55. A Comminuted Fracture of Vault and Base, the Basic Fracture Involving both Middle and Posterior Fossæ. The middle fossa fracture, on the left side, follows the usual course. The posterior fossa fracture resulted in laceration of both lateral sinuses—at the usual site, junction of sigmoid and lateral sinuses. Probes are inserted at each site of laceration. The resultant hæmorrhage was mainly intradural, but, as is seen in this figure, the dura mater of the posterior fossa is stripped away from the bone by an extra-dural extravasation.