the common carotid or the vertebral artery in the neck,
according to the seat of the aneurysm.

#Orbital Aneurysm.#--The term pulsating exophthalmos is employed to
embrace a number of pathological conditions, including aneurysm, in
which the chief symptoms are pulsation in the orbit and protrusion of
the eyeball. There may be, in addition, congestion and oedema of the
eyelids, and a distinct thrill and murmur, which can be controlled by
compression of the common carotid in the neck. Varying degrees of ocular
paralysis and of interference with vision may also be present.

These symptoms are due, in the majority of cases, to an aneurysmal varix
of the internal carotid artery and cavernous sinus, which is often
traumatic in origin, being produced either by fracture of the base of
the skull or by a punctured wound of the orbit. In other cases they are
due to aneurysm of the ophthalmic artery, to thrombosis of the cavernous
sinus, and, in rare instances, to cirsoid aneurysm.

If compression of the common carotid is found to arrest the pulsation,
ligation of this vessel is indicated.

#Subclavian Aneurysm.#--Subclavian aneurysm is usually met with in men
who follow occupations involving constant use of the shoulder--for
example, dock-porters and coal-heavers. It is more common on the right
side.

The aneurysm usually springs from the third part of the artery, and
appears as a tense, rounded, pulsatile swelling just above the clavicle
and to the outer side of the sterno-mastoid muscle. It occasionally
extends towards the thorax, where it may become adherent to the pleura.
The radial pulse on the same side is small and delayed. Congestion and
oedema of the arm, with pain, numbness, and muscular weakness, may result
from pressure on the veins and nerves as they pass under the clavicle;
and pressure on the phrenic nerve may induce hiccough. The aneurysm is
of slow growth, and occasionally undergoes spontaneous cure.

The conditions most likely to be mistaken for it are a soft, rapidly
growing sarcoma, and a normal artery raised on a cervical rib.

On account of the relations of the artery and of its branches, treatment
is attended with greater difficulty and danger in subclavian than in
almost any other form of external aneurysm. The available operative
measures are proximal ligation of the innominate, and distal ligation.
In some cases it has been found necessary to combine distal ligation
with amputation at the shoulder-