On humans, the inferior nuchal lines are on the bottom back of the skull very close to where the spinal cord enters the skull (occiput nearest the foramen magnum). These ridges extend from the midline to both left and right, curving around the foramen. When Bones says the burn marks are normally equidistant to the inferior nuchal line but are now angled 4 cm. to the right, her terms are woefully imprecise because those lines curve around the skull. Describing the burn positions relative to the midline of a specific cervical vertebrae would be more precise but sound less impressive.
David Boreanaz and Noel Fisher have both played Vampires. David as Angel on Buffy and Angel. Noel as Vladimir in Breaking Dawn 2.