The question of how many vertebrae are in the human spine seems, at first, to be a simple one. The generally accepted answer is 33; this is the total number of bony structures referred to by the anatomist as making up the spinal column.
But this number doesn’t really do much more than illuminate how many bones are in the spine in a general sense. When doctors and other health practitioners talk about our aching backs, they tend to use some jargon that we don’t in every day conversation and it can be very helpful to understand more of the basic anatomy of the spine—and some of the terms that are applied to this most important and sometimes most troublesome part of our bodies.
Only 24 of the bones in our backs are what is referred to as “articulated”, that is, separate and discrete and spaced apart by “intervertebral” cartilage disks. The balance, 9 vertebrae in total, are fused structures, and these are more technically referred to by their group names; the five bones of the “sacrum” and the four bones of the “coccyx” or tailbone.
The 24 articulated vertebrae are further broken down into groups of their own. The uppermost seven are referred to as “cervical”; the middle region of the spine, comprised of 12 vertebrae is “thoracic” and the remaining five of the articulated structures are known as “lumbar”.
Spine (Vertebrae) Groups:
- The cervical spinal structures support the head and allow its movement. These vertebrae are the smallest and generally the most flexible. The bones of the thoracic group, sometimes referred to as “dorsal vertebrae” have as their main function the support of the rib cage, and do not allow for much bending or stretching.
- The largest and some might say most problematic vertebrae are found in the lumbar region, which we commonly think of as the “small of our back", where the inward curve of a healthy spine occurs. These bones are prone to trouble because by far they support most of the body’s weight and are capable of a wider range of motion than their fellows, including “flexion” or bending; extension or stretching; some rotation and side to side movement.
- The sacrum and coccyx, as stated previously are fused together with no spaces between –and serve as the anchor to the rest of the spine. Pain here is not unheard of, of course, but the fused nature of these areas means “less moving parts” and a somewhat reduced tendency toward injury.
The Spinal Cord
The spine, of course, it not just the column which supports our bodies, it also encases and protects our spinal cords. The spinal cord is the complex pathway of nerves extending down from our brains that allow us all movement, including the basic functions of breathing and blood flow. The bony structures, disks, arteries, blood vessels and nerves make this a complex system in which many things may go wrong.
This in turn can make the treatment of back pain difficult to formulate and implement, because the causes and source of discomfort can be nearly impossible to pinpoint, and injury or strain to one system can transmit pain impulses throughout the entire body.
By knowing a bit more about your spine and its structure, you can better understand what your doctor is telling you and communicate to those involved in the treatment of your bad back where your pain originates. Always be an active participant in your own health and in any medical treatment undertaken, and don’t be afraid to speak up and ask question, especially when the doctors start to rattle off technical jargon!