Feel that pulse in the side of your neck, the one the paramedics on TV shows reach for to check if someone’s heart has stopped? The carotid arteries are the major blood supply to the head. Specifically, branches called internal carotids, one on each side of your neck, are the major blood supply to the brain. In ancient times people discovered that animals could be “put to sleep”, rendered unconscious, by pressing on both of these vessels. Therefore, it should come as no surprise that the Greek word for these arteries means “to stupefy or make sleepy”.