What are vertebrae?

These are the disk-shaped bones that provide strength and flexibility to the spine.  With exception of the the two top vertebrae, the sacrum, and the coccyx, all the vertebrae are similar in size and function.  The main part of a vertebra, called the body, is a flattened round block of bone.  From the body sprout two cylinder-shaped bones called pedicles.  The pedicles attach to small plates of bone (called laminae) that surround a central opening for the spinal cord.  Three wing-like extensions poke in three directions from the laminae.  The transverse processes poke to the sides and the spinous process pokes straight out to the back.  The spinous processes are what give the back a bumpy appearance on the skin.  The processes are anchor points for muscles.  Vertebrae also have connection points for other vertebra called articular processes and facets.  The ribs attach to the thoracic vertebrae at attachement points called the costal facets.

The 7 cervical vertebrae attach your head to you shoulders.  They allow the neck to bend.

The 12 thoracic vertebrae are attached to the ribs and aren't very bendable.

The 5 lumbar vertebrae allow you to twist your torso and bend your back.

 Who is Atlas and what does he have to do with the spine?

Atlas was a Titan in Greek mythology who was condemned to carry the world on his shoulders.  The uppermost bone of the spinal column is named atlas also, because it carries the weight of the skull.  It is a ring-shaped bone that has strong ligament attachments that connect the spine to the skull.  Imagine balancing a bowling ball on a broomstick!

What is the axis bone and what does it do?

The axis bone is the second vertebrae down from the top of the spine.  The axis bone has a central knob that points upward through the central hole of the atlas bone.  The axis provides a pivot point for the atlas (which is holding the skull).  This allows us to turn our heads.

What is the sacrum?

The sacrum is a shield-like bone that protects the lower spine.

What is the coccyx and what is it for?

 The coccyx... well, it is there because... hmmmm... I don't know.  It is similar to the tail bone in monkeys.  It is the only spine bone without a known function.

What's an intervertebral disc?

These are little "pillows" between vertebrae that help cushion and add flexibility to the spine.  Without these discs, your vertebrae would crunch together when you jumped up and down.  

Why is the spine curved?

The curves of the spine help add strength, balance and flexibility.  When this curve bends to far to the front it is called kyphosis (hunch back).  When the curve is excessive to the back it is called lordosis (swayback).

What is scoliosis?

The normal curves of the spine go from front to back.  It is common for children (and adults) to have some mild spinal curve to one side or the other.  When this curve is extrem, it is called scoliosis.  Scoliosis can cause problems with posture that may lead to back pain or weakness.

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