Each of your vertebrae are labeled starting with your neck (cervical spine) and they are C1 through C7 respectively, starting at the base of your skull and going downward. Then they reach the thoracic spine (chest area) where they are numbered beginning with a T, and then your lumbar spine (lower back) beginning with a L, and then a few at the very bottom which start with an S (don't remember what the S stands for). The levels they refer to such as C5-6 and C6-7, are the disc spaces between C5 and C6, and between C6 and C7. If someone had a single level fusion, it would mean they removed the disc between two vertebrae and fused two vertebrae together with a bone wedge in between. I hope I didn't just confuse things and make it that much worse!!
Keith
Levels 
Linear Mode
