_1_, Common carotid artery; _2_, thyro-laryngeal; _3_, thyroid; _4_,
laryngeal; _5_, pharyngeal; _6_, occipital; _7_, condyloid; _8_,
middle meningeal; _9_, pharyngeal; _10_, external maxillary; _11_,
lingual; _12_, sublingual; _13_, superior labial; _14_, internal
maxillary; _15_, masseteric; _16_, inferior alveolar; _17_,
buccinator; _18_, great palatine; _19_, sphenopalatine; _20_,
posterior auricular; _21_, superficial temporal; _22_, posterior
meningeal; _23_, anterior auricular; _24_, artery to matrix of horn;
_25_, deep temporal; _26_, arteries to rete mirabile; _27_, frontal;
_28_, malar; _28′_, dorsal nasal continuation of malar; _29_,
infraorbital; _29′_, lateral nasal continuation of _29_.
]
The =carotid arteries= usually arise from a common trunk about two
inches (ca. 5 cm.) in length, but in exceptional cases are given off
separately from the brachiocephalic. Each pursues a course similar to
that of the horse and is accompanied by the small internal jugular vein,
but is separated from the external jugular vein by the omo-hyoid and
sterno-mastoid muscles. It divides at the digastricus into occipital,
external maxillary, and external carotid arteries. In addition to
tracheal, œsophageal, and muscular branches, it gives off the thyroid
and laryngeal arteries. The =thyroid artery= (A. thyreoidea cranialis)
bends around the anterior end of the thyroid gland, in which it
ramifies. The accessory thyroid artery is usually absent. The =laryngeal
artery= may arise with the thyroid.