Spine

For the network of nerves inside the spine, see Spinal cord.

The spine is a column of vertebrae in the back part of the torso (upper body). It is also called the backbone or vertebral column. There is a spinal canal that runs through the length of the spine. Inside this canal is the spinal cord. Animals that have a spine are called vertebrates, and animals that do not have one are called invertebrates. Humans have a spine, so we are vertebrates. Many vertebrates, including mammals, have intervertebral discs separating the vertebrae.

The vertebral column as seen from the side

A typical thoracic vertebra viewed from above. The unlabeled hole in the middle will form the Spinal canal

An MRI of the human spine. The part in blue is the spinal canal. It also shows that one vertebra has been broken (L-3), which means that the spinal cord is compressed at one point (L-3,L-4 impingement) .

Regions

The vertebral column has five regions. These regions from top to bottom are:

• Cervical - Shown in red, this region supports the head. It is made up of 7 vertebrae. The first two, called the atlas and axis, connect the spine to the skull.
• Thoracic - Shown in blue, this region supports the ribs. It is made up of 12 vertebrae.
• Lumbar - Shown in yellow, this region is located in the lower back. It is made up of 5 vertebrae.
• Sacral - Shown in green. It is made up of 5 vertebrae that are fused together.
• Coccygeal - Shown in purple. It is made up of 3 to 5 vertebrae.

Spinal canal

The spinal column has an opening called spinal canal and this opening is used for nerves. The part of the central nervous system in the spinal column is called spinal cord.