The Spinal Column

The puropse of the spinal column is to protect the spinal cord by enclosing it in a protective "casing" and also to provide support for the body and head. The spinal column is capable of extreme flexiblity, which allows the body to be free to move in a number of directions. The spinal column is formed by a number of smaller bones known as vertebrae. and shock absorbing discs which separate and cushion the vertebrae.

Facet Joints:

Facet joints, or spinal joints, as they are normally referred, attach neighboring vertebrae to one another. Facet joints are similar to hinges and provide vertebrae with the ability to move in multiple directions, allowing the body to twist while still maintaining a range of motion within normal parameters. The surfaces of the facet joints are covered with cartilage that lets them slide against each other in a smooth manner. Further supporting the spine are a series of muscles, ligaments and discs.

Ligaments:

Ligaments are coarse bundles of dense white fibrous tissue which connect the vertebrae and strengthen the joints. Facet joints and ligaments help protect the spine by limiting how far the spine can bend or twist.

Muscles:

Muscles are body tissue composed of long cells that contract when stimulated, and assist in maintaining the structure of the back, while allowing us movement. The back and abdominal muscles support the thoracic spine and the ribcage, while the buttocks support the coccyx and sacrum. These muscles help the spine by absorbing the shocks prior to causing damage to the skeletal structure of the back.

Spinal Cord:

The spinal cord begins at the brain and runs down to the level of the second lumbar vertebrae. The lumbar spinal nerves join to form the sciatic nerve. Spinal nerves branch out form the spinal cord.

Sciatic nerve:

The sciatic nerve branches off nerve roots off the lower end of the spinal cord. (The spinal cord ends in the lower back) Two branches run through the pelvis, deep into each side of the buttocks, through the hip, the backside of the upper leg down to the foot. . The sciatic nerve is the largest nerve in the human body - the diameter of a finger.

Discs:

The vertebrae are separated by shock absorbing intervertebral discs. Theses discs have a tough outer coating with and contain a jelly-like substance.

Vertebrae:

The 24 vertebrae are named according to their location along the spine. We start out with 33 vertebrae but the lowest nine fuse together to form single bones- 5 fused vertebrae form the sacrum and 4 tiny fused vertebrae form the coccyx (tailbone).

The 24 vertebrae:

Cervical spine (neck area) with 7 vertebrae (labeled C1 - C7)

Thoracic spine (chest area) with 12 vertebrae (labeled T1 - T12)

Lumbar spine (lower back) with 5 vertebrae (labeled L1 - L5)

Below the lumbar spine:

Sacrum: a triangular shaped solid base with 5 fused vertebrae - connects with the pelvis

Coccyx: (the tailbone) with 4 very small fused vertebrae.

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