fracture is compound, the blood can escape, and therefore the
pressure symptoms are less evident or may be entirely absent.

It is a fact of some medico-legal importance that haemorrhage from the
middle meningeal may not take place till some days, or even weeks,
after an injury, which at the time was only attended with symptoms of
concussion. This condition is known as _traumatic apoplexy_.

_Treatment._--Immediate operation is imperatively called for, not only
to arrest the haemorrhage and remove the clot, but also to ward off the
oedema of the brain, which is often responsible for the fatal issue.
When there is no external wound, the point at which the skull is to be
opened is determined by the symptoms; for example, paralysis of the
arm and face on one side indicates trephining over the centres
governing these parts on the side opposite to the paralysis.

If the bleeding cannot otherwise be arrested it may be necessary to
ligate the external carotid artery. It has been suggested by J. B.
Murphy that, when the patient is seen while the symptoms of
compression are coming on, instead of trephining, the haemorrhage from
the meningeal vessels should be arrested by applying a ligature to the
external carotid, under local anaesthesia.

Injury to the #internal carotid# artery within the skull may result
from penetrating wounds, or may be associated with a fracture of the
base. It is almost invariably fatal. In some cases a communication is
established between the artery and the cavernous sinus, and an
arterio-venous aneurysm is thus produced. Ligation of the internal
carotid in the neck or of the common carotid is the only feasible
treatment.

Injuries of the #venous sinuses# may occur apart from gross lesions of
the skull, but as a rule they accompany fractures and penetrating
wounds. The transverse (lateral), superior sagittal (longitudinal),
and cavernous sinuses are those most frequently damaged. On account of
the low pressure in the sinuses, spontaneous arrest of extra-dural
haemorrhage usually takes place, and recovery ensues. In some cases,
however, the amount of blood extravasated is sufficient to cause
compression. If the dura mater is torn, and the blood passes into the
sub-arachnoid space, it may spread over the whole surface of the
brain. Sometimes the bleeding only commences after a depressed
fracture has been elevated.

In the presence of an open wound, the venous source of the bleeding is
recognised by