Almost 80% of people will suffer from back pain at least once in their lifetime and it is the most common medical complaint in North America. If ignored, back problems can become chronic and even disabling, however there is relief and it is important to understand the complicated structure of the back and vertebrae and their joints.
The Vertebral Column
The two main parts of the back are the spine or vertebral column and the back muscles, which are attached to the spine by strong ligaments. The spine consists of bones called vertebrae which are arranged stacked upon each other from the tailbone to the head. The vertebrae are joined to each other by facet joints.
There are 33 vertebrae divided into 5 regions: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal. Motion occurs between only the cervical, thoracic and lumbar vertebrae.
Soft cushion-like discs separate these vertebrae, allowing the spine to bend and flex somewhat. The discs act as cushions between the vertebrae and absorb shock and vibration produced during walking and running. They contain a soft central area called the nucleus pulposus surrounded by a tougher outer part called the annulus fibrosus which holds the vertebrae together and prevents the nucleus pulposus from pushing out.
The Spinal Cord and Nerves
The vertebral column protect the spinal cord which runs through the spinal canal, an opening in the center of each vertebra. Nerves connecting the brain to the body make up the spinal cord and branch off to the body's organs, systems and muscles including the arms and legs.
These nerves carry sensation from the limbs and body back through the spinal cord to the brain. The spine is joined to the pelvis or hip bones by the sacroiliac joints.
The vertebrae increase in size down the spinal column until the sacral vertebrae and then get smaller. There are also four curvatures in the adult spine: these provide further flexible support and shock-absorbing resilience from everyday movements such as walking.
The Muscles of the Back
Most of the body's weight is in front of the spine and back, especially in obese people and anyone with excess baggage around the middle. Therefore the back requires many strong muscles to support the weight of the body and move the vertebral column. Hence, there are three groups of muscles that work together as intricate systems of support and movement, not only in the back but in other parts of the body as well. The superficial or intermediate and intrinsic muscles produce and control limb movements and even help the lungs in respiration. The deep group of muscles act specifically on the vertebral column producing it's movement and maintaining posture.
The shape and structure of the vertebrae, discs, ligaments and muscles provide the stability and strength of the back. This complicated system is prone to injury and pain, hence it is very important to understand the structure of the back to maintain overall health.
