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.