The left common carotid, and the left subclavian artery, come directly off the aortic arch.

It occasionally arises from the aorta, the right common carotid, the subclavian or the internal mammary.

The right common carotid originates in the neck from the brachiocephalic trunk.

The right common carotid originates in or close to the neck, so contains a small thoracic portion.

The cervical portions of the common carotids resemble each other so closely that one description will apply to both.

The left common carotid varies in its origin more than the right.

Occasionally, it arises from the aorta, the right common carotid, the subclavian or the internal thoracic artery.

Dr. Jones said, very simply, "I think his right common carotid is blocked.

Stephen bent over him, catling in hand, felt for the still beating common carotid, severed it, and stood back from the jet of blood.

If it wasn't, I could easily lacerate the common carotid or the internal jugular, and he'd bleed to death right under my hands.