tic tumours and
abscesses in the neck are sometimes more difficult to differentiate on
account of the apparently expansile character of the pulsation
transmitted to them. The fact that compression of the vessel does not
affect the size and tension of these fluid swellings is useful in
distinguishing them from aneurysm.

_Treatment._--Digital compression of the vessel against the transverse
process of the sixth cervical vertebra--the "carotid tubercle"--has been
successfully employed in the treatment of aneurysm near the bifurcation.
Proximal ligation in the case of high aneurysms, or distal ligation in
those situated at the root of the neck, is more certain. Extirpation of
the sac is probably the best method of treatment, especially in those of
traumatic origin. These operations are attended with considerable risk
of hemiplegia from interference with the blood supply of the brain.

The _external carotid_ and the cervical portion of the _internal
carotid_ are seldom the primary seat of aneurysm, although they are
liable to be implicated by the upward spread of an aneurysm at the
bifurcation of the common trunk. In addition to the ordinary signs of
aneurysm, the clinical manifestations are chiefly referable to pressure
on the pharynx and larynx, and on the hypoglossal nerve. Aneurysm of the
internal carotid is of special importance on account of the way in which
it bulges into the pharynx in the region of the tonsil, in some cases
closely simulating a tonsillar abscess. Cases are on record in which
such an aneurysm has been mistaken for an abscess and incised, with
disastrous results.

_Aneurysmal varix_ may occur in the neck as a result of stabs or bullet
wounds. The communication is usually between the common carotid artery
and the internal jugular vein. The resulting interference with the
cerebral circulation causes headache, giddiness, and other brain
symptoms, and a persistent loud murmur is usually a source of annoyance
to the patient and may be sufficient indication for operative treatment.

#Intracranial aneurysm# involves the internal carotid and its branches,
or the basilar artery, and appears to be more frequently associated with
syphilis and with valvular disease of the heart than are external
aneurysms. It gives rise to symptoms similar to those of other
intracranial tumours, and there is sometimes a loud murmur. It usually
proves fatal by rupture, and intracranial haemorrhage. The treatment is
to ligate