Learn About the Our Backbone - Spine

There are 33 vertebrae altogether, although some of these fuse or join as the body grows.

The spinal cord has 31 segments. From each segment, motor nerve roots leave from the ventral side, and sensory nerve roots enter from the dorsal side. The ventral and dorsal roots join to form paired 'spinal nerves', one on each side of the spinal cord.

There are 31 spinal cord segments:

• 8 cervical segments
  
• 12 thoracic segments
  
• 5 lumbar segments
  
• 5 sacral segments
  
• 1 coccygeal segment
  

Each vertebra is linked to the next by facet joints, which are like tiny ball-and-socket joints. The spinal cord carries messages to and from the arms, legs and trunk of the body

cc licensed flickr photo shared by bixentro

The vertebrae are separated by discs of rubbery material called cartilage. These cushion the bones when you run and jump.

The bones of the spine are divided into five groups from top to bottom. These are the cervical
(7 bones), the thoracic (12 bones), the lumbar

cc licensed flickr photo shared by planetc1

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