tself or its sheath,
and is likely to be included in the ligature oftener than we are aware
of.

The trunk of the external carotid, D, Plate 5, is in all cases very
short, and in many bodies can scarcely be said to exist, in consequence
of the thyroid, lingual, facial, temporal, and occipital branches,
springing directly from almost the same point at which the common
carotid gives off the internal carotid artery. The internal carotid is
certainly the continuation of the common arterial trunk, while the
vessel named external carotid is only a series of its branches. If the
greater size of the internal carotid artery, compared to that of the
external carotid, be not sufficient to prove that the former is the
proper continuation of the common carotid, a fact may be drawn from
comparative philosophy which will put the question beyond doubt,
namely--that as the common carotid follows the line of the cervical
vertebrae, just as the aorta follows that of the vertebrae of the trunk,
so does the internal carotid follow the line of the cephalic vertebrae.
I liken, therefore, those branches of the so-called external carotid to
be, as it were, the visceral arteries of the face and neck. It would be
quite possible to demonstrate this point of analogy, were this the place
for analogical reasoning.

The common carotid, or the internal, may be compressed against the
rectus capitis anticus major muscle, 13, Plate 6, as it lies on the
fore-part of the vertebral column. The internal maxillary artery, 16,
Plate 6, and the facial artery, G, Plate 5, are those vessels which
bleed when the lower maxilla is amputated. In this operation, the
temporal artery, 15, Plate 6, will hardly escape being divided also, it
lies in such close proximity to the neck and condyle of the jaw-bone.

The subclavian artery, B Q, Plate 5, traverses the root of the neck, in
an arched direction from the sterno-clavicular articulation to the
middle of the shaft of the clavicle, beneath which it passes, being
destined for the arm. In general, this vessel rises to a level
considerably above the clavicle; and all that portion of the arching
course which it makes at this situation over the first rib has become
the subject of operation. The middle of this arching subclavian artery
is (by as much as the thickness of the scalenus muscle, X, Plate 5)
deeper situated than either extremity of the arch of this vessel, and
deeper also than any part of the common carotid, by th