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BLOOD-VESSEL SYSTEM OF THE HEAD, ETC. 221

cle is sometimes a separate and distinct branch of the common carotid.
It occasionally gives origin to the ascending pharyngeal artery, and its
hyoid branch is often very small or entirely absent. The snperior
laryngeal branch also often arises from the external carotid, and occa-
sionally from the common carotid, and may pierce the crico-thyroid
space or pass.throngh a foramen in the thyroid cartilage. The crico-
thyroid branch is sometimes of considerable size, and may interchange
with a branch to the thyroid body or a division of the inferior thyroid
artery.

The Lingual Artery.
The lingual artery is about 3|^ mm. (^ inch) in calibre, and is the
second anterior branch of the external carotid. It arises Mithin the
carotid triangle between the snperior thyroid and facial arteries, and
nearly opposite the great cornu of the hyoid bone. It passes upward a
short distance, then turns downward, forming a concavity which is crossed
by the hypoglossal nerve. Thence it extends beneath the digastric and
stylo-hyoid muscles to reach the great cornu of the hyoid bone, running
parallel with it, under cover of the hyo-glossus muscle, to a point near
its anterior border, where it turns upward and passes to the under sur-
face of the tongue, through which it extends to the tip, where it termi-
nates in the ranine artery.
Relations.—This artery is divided into four portions, according to
the regions through which it passes. The first or superficial portion
is wholly within the carotid triangle, and is covered by the skin,
platysma myoides, and fascia of the neck, and rests upon the connective
tissue and middle constrictor muscle of the pharynx. The second or
horizontal portion is covered externally by the sterno-hyoid, digastric,
and the greater part of the hyo-glossus muscle, the hypoglossal nerve
passing to the outer side of the muscles : this portion of the artery
rests uj)on the middle constrictor muscle of the pharynx. The third or
ascending portion is that part which extends upward to the under sur-
face of the tongue : it passes between the hyo-glossus and genio-glossus
muscles. The fourth or ranine portion is generally in relation whh the
intrinsic muscles of the anterior part of the tongue. Near its termina-
tion it becomes quite superficial and communicates with its fellow of the
opposite side.
The branches of the lingual artery are the hyoid, dorsalis lingual,
sublingual, and ranine arteries.
The Hyoid or Superior Hyoid Artery is the first branch of the lin-
gual, and arises within the carotid triangle. It passes to the upper
border of the hyoid bone, supplying the bone, the muscles attached
to its upper portion, and the fiJDro-adipose tissue between the bone
and the base of the epiglottis.
The Dorsalis Lingual Artery, which is occasionally replaced by sev-
eral smaller ones, arises from the second ]5art of the lingual artery as it
passes beneath the hyo-glossus muscle. It extends to the upper surfiice
of the tongue, sup])lies the mucous membrane of this surface, as Avell as
the substance of the organ, and communicates with its fellow of the