Structural Components of the Spine

Peer Reviewed

To understand what causes back pain, here is a short anatomy lesson. This overview will help you understand your spine specialist and you will understand better what treatment your doctor is recommending for you.

Cervical, Thoracic and Lumbar Spine
Your spine is made up of 24 vertebrae. Each vertebra is made up of the vertebral body in the front, the facet joints in the back and the pedicles, which connect the vertebral body to the facet joints. The human spine is divided into three sections: 1) the cervical spine or neck is made up of 7 vertebrae, 2) the thoracic spine made up of 12 vertebrae and 3) the lumbar spine or low back which consists of 5 vertebrae.

Intervertebral Discs

normal disc
The discs are located between each vertebra allowing for bending, twisting and shock-absorption. A herniated disc is sometimes mistakenly referred to as a "slipped disc". In reality there is no such thing as a slipped disc. Discs cannot slip because they are attached to the vertebrae above and below by strong ligaments.

When a disc herniates, the jelly center squeezes out through the disc wall putting pressure against a nerve. While pain in the back and leg from pressure on the nerve can be relieved by various treatments, the damage done to the disc will be permanent and may have real consequences. Aging also results in a decrease in blood supply to the disc by age 20. Dehydration also occurs with aging. This leads to a flatter, drier disc more susceptible to herniation. Regular exercise helps to prevent injury through self-lubrication and increased blood flow.


sciatica nerve
Nerves in the lower back come together to form the sciatic nerve, which runs down the back of the leg. A "pinched nerve" from a herniated disc can cause pain down the back of the leg sometimes referred to as "sciatica".

Facet Joints

vertebrae, discs, joints, pedicles
In the back of the spine hinge-like structures called facet joints are located. These joints link the vertebrae together along with the discs in front allowing for complex spinal motion. These joints may be injured by lifting or straining, severe twisting or hyperextension. Rest, ice and a few Aspirin will often help the pain. Facet injections with a small amount of anesthetic and cortisone are sometimes performed in resistant cases.

Spinal Muscles

paraspinal muscles
It is estimated that most back pain is caused by soft tissue injury such as muscle strain. Our back muscles allow us to stand straight and lift things. In the normal situation, the back muscles contract and relax as the back moves. But under strain, the poorly conditioned muscle can spasm, tensing up until it becomes a hard painful knot.

The pain may be quite severe. Fortunately, with rest, ice and a few aspirin, the pain will often subside. Stretching and exercise will help prevent repeat strains.

 Material © SpineSource  spinesource logo regan  Used By Permission
Updated on: 02/01/10
Mary Rodts, DNP
Understanding the terminology associated with spinal problems is very important as health care providers discuss the problems and the solutions for the spinal disorder with patients and families. This article helps clarify a difficult topic.