When viewed from the side, a healthy spinal column is slightly S-shaped. The top seven vertebrae are known as the cervical vertebrae, labeled C1 through C7.
The chest area contains the thoracic vertebrae, T-1 through T-12. The thoracic vertebrae do not rotate as much as the neck and low back. Consequently, this area of the spine is more stable and is generally less susceptible to injury. Relatively few back pain cases involve the T-level vertebrae.
Below the thoracic vertebrae are the five lumbar vertebrae, and below that is the sacrum. The lumbar vertebrae are labeled L1 to L5. This area is the most prone to injury, because it bears the most weight when you sit, stand, push, pull or lift.
Below the lumbar spine area is a series of fused bones known as the sacrum. At the bottom tip of the spinal column structure is the coccyx or the tailbone.
Each rounded vertebra body has pedicles and laminae, facet joints, and the bony transverse and spinous processes, which are the narrow, finger-like spikes pointing out from the sides and back of the vertebra.
This spinal column is held in place by surrounding muscles, ligaments and tendons that act as supporting guy wires. When working properly, the spine is able to bend and twist. When muscles and ligaments weaken, problems arise in the stability of the spine. Muscles and ligaments can strain, and discs and facet joints can be injured.