Have you ever been diagnosed with "military neck"? It basically means that your neck curve is straight and not the proper c curve that it should be. It is also known as loss of cervical lordosis or having a hypolordotic curve in the neck spine (loss of the cervical curve, the spine may not be completely straight but there is a loss of curve there.
Let me start off by describing what correct neck alignment is. Ideal alignment is having your neck straight up and down when looking at your posture from the front or back. When looking from the side you should have a smoothing flowing C-curvature. This squidoo lens will showcase for you what a normal and abnormal neck curve look like on x-ray.