I recently received an email from a yoga teacher buddy asking how many vertebrae we have in our spines, specifically how many cervical vertebrae. "Is it 7 or 8?" This may clear things up.
How many vertebrae do we have?
The easiest way to remember the number of vertebrae in a normal spine is to remember your meal times. Start with breakfast at 7, have lunch at 12 and then an early dinner at 5. Starting from the top of your spine, you have 7 cervical vertebrae, 12 thoracic vertebrae and 5 lumbar vertebrae. The cervical are in your neck region, the thoracic in your chest region and the lumbar are in your low back. These vertebrae are named by the first letter or their regions and their numbers. For example, the 3rd cervical vertebra (counting from the top down) would be C3, and the second lumbar vertebra would be L2 and so on.
Adding that up... 7+12+5=24! But wait! If you look up how many vertebrae we have everything says 33! How can that be? The answer is in your sacrum and coccyx (tailbone). The sacrum is actually made of 5 fused vertebrae and your coccyx is made of 4. So all together we have 33 vertebrae.
Adding that up... 7+12+5=24! But wait! If you look up how many vertebrae we have everything says 33! How can that be? The answer is in your sacrum and coccyx (tailbone). The sacrum is actually made of 5 fused vertebrae and your coccyx is made of 4. So all together we have 33 vertebrae.
Then what the heck is C8?!?

The confusion of the mysterious 8th vertebra comes from the very similar or same naming of the spinal nerves. All your vertebrae stack on each other to form your spine, and inside your spine is your spinal cord carrying information into or out from your brain.
At each vertebral level, spinal nerves come out to send information to your arms, legs and organs etc, and also bring information back in. These nerves are also named the same way, by region and number. Even though there are only 7 cervical vertebrae, there are 8 cervical spinal cord segments and spinal nerves. This is where we get the C8. I've always thought that they should have found a better way to name this, but they didn't, so we have to live with it! Just remember when talking about C4, T5, L5 or whatever level, we can be talking about the vertebra or the spinal nerve. I hope that clears things up!
Namasté
Breakfast lunch dinner photo from http://sweetnomore.files.wordpress.com/2013/01/breakfast.jpg. Spinal segments image from Thieme's Atlas of Anatomy by Gilroy et. al.