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 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.