Carotid Arteries

The common carotid arteries run up each side of the neck beside the larynx and trachea, dividing into the internal and external carotids near the upper border of the thyroid cartilage.

The carotid arteries carry blood from the heart to the brain (internal carotids) and to the face and neck (external carotids).

Radiation can accelerate narrowing of the carotid arteries (carotid stenosis) years after treatment, raising the risk of stroke. When the neck nodes are treated the carotids sit inside the target, so sparing is possible mainly when the neck is not treated — as in early glottic cancer, where the carotids lie right beside a small larynx field.

Brouwer 2015 includes the common and internal carotid arteries and leaves out the external carotid.

• The right common carotid starts in the neck from the brachiocephalic trunk; the left starts from the aortic arch in the chest. Above that they follow the same course.
• They divide into external and internal carotids at about the level of C4. The bifurcation level varies naturally between people.
• Top: the internal carotid contour ends at the upper part of the optic chiasm.