Learn About Your Back and Back Pain

Today back pain is one of the most common of all physical complaints in the world. 70 to 90% of men and women in the U.S. have had or will have a least one bout of incapacitating lower back pain. Back pain contributes to lost work time and may cost as much as $100 billion annually (if lost productivity is included). Hence, the importance of an inversion table review is to see what works.

Doctors generally agree that most back problems are caused by stress or by weak muscles. We need a strong back, stomach, and hip muscles to resist gravity and to hold us up. As societies around the world have become more mechanized and computerized, they have also become less exercised. We lock ourselves behind desks and in front of computers. When we sit, our back muscles hold us erect, but our stomach and hip muscles are inactive. When they are not exercised, stomach and hip muscles become weaker, putting a painful strain on the back muscles. Sitting places higher loads inside the lumbar disc than standing (between 150% to 250%, depending on posture).

The condition of your back is very important to your health. A better back can lead to a better body.

Anatomy of the Back

Briefly explained, your spine is made up of the following components:

• Vertebrae – the bones that make up your spine
• Nerves – your entire nerve system runs through your spine
• Discs – spongy material that separates your vertebrae, allowing the nerves to run between each bone segment. Discs act like shock absorbers and allow the spine to flex.

Each vertebrae is held in its proper place by three different kinds of soft tissue–discs, ligaments, and muscles. Almost all back problems are related to the dysfunction of one of these three. To understand the sources of your particular back problem and/or how to prevent back pain, it helps to understand the anatomy of your spine.

The natural curves of the spine are vitally important for giving your back strength and resilience. There are 24 vertebrae in your spinal column. The lumbar vertebrae are approximately two inches in diameter reflecting their weight-bearing role. The cervical vertebrae are smaller since they must support only the head. Facet joints are located in pairs on the back of the spine, where one vertebra slightly overlaps the next. The facet joints guide and restrict movement of the spine. To the rear of each vertebra is a hole and when the vertebrae are stacked up; these holes form a continuous channel which holds the spinal cord.

The spinal cord provides a vital link between the brain and all body functions below the neck. Spinal nerves emerge from the spinal cord through gaps between the main body of the vertebrae and the facet joints. One frequent cause of back pain is a worn facet joint, which can result in a pinched nerve. Therefore, it is very important to keep your vertebrae in good shape.

The main function of your discs is to act as shock absorbers and provide separation between each vertebrae. The outer layers of your discs are formed from tough cartilage. The inner core of your disc is a jelly-like nucleus.

In total, your discs account for one-quarter the length of your vertebral column–4.50″- 6″ (12 to 15 cm) for most people. The disc acquires its nourishment through fluid-attracting and fluid-absorbing qualities of its jelly-like nucleus. With no blood supply of its own, the disc is dependent on sponge-like movement for attracting and absorbing nutrients from adjacent tissues.

During weight bearing activities (sitting, standing, exercising), some of the fluid in the disc is lost into the adjacent soft tissue. This can actually cause the length of the spine to decrease by as much as 1/2″ to 3/4″ daily. During non-weight bearing activities (when sleeping), the discs expand as they soak up fluid. However, the discs don’t fully recover the lost fluid, and over a lifetime, overall spinal length can diminish by 1/2″ to 2″.

Your vertebra are supported and moved by many different muscles. Muscles are used for three basic functions: support, movement, and posture control. If muscles are tight or weak, they create or worsen back pain. Joints are controlled by at least two sets of muscles, flexors which bend the joint, and extensors which straighten it. In addition, most joints have rotator muscles that twist and rotate your bones. Good posture is only possible if the flexors, extensors, and rotators are in proper balance.

Your paraspinal muscles (which run parallel to your spine) rotate your spine, bend it backwards, and sideways, and influence posture by creating and maintaining the curves of your spine. Your erector spine muscles are involved in movement and run the length of your spine. These muscles help you to bend over by resisting the force of gravity, and to straighten up by contracting and exerting great compressive force on your spine.

Your abdominal muscles play an important role in helping to support the spine by maintaining pressure inside the abdomen. This pressure is an essential measure of counter support to the spine.

Your psoas muscles (hip flexors) are a large group of muscles in the abdomen. These muscles help to flex your hips when walking or climbing stairs. They play an important role in maintaining posture for sitting and standing.

Intravertebral joints are supported by ligaments, tough and inelastic fibers which support the spine and hold it together by allowing only a limited range of movement in any one direction. Ligaments require regular movement and loading, otherwise they will eventually become stiff and weak.

Summary

• There are 24 vertebrae in your back which encase your spinal cord.
• Spinal nerves run through each vertebral joint in your spinal column.
• Your discs act as shock absorbers.
• With no blood supply of their own, discs depend on sponge-like action to soak up nutrients.
• Muscles and ligaments require regular movement in order to maintain flexibility.

Some Interesting Statistics on Back Pain

• Four out of five adults (80% of the population) experience significant low back pain at some point in their lives.
• 31 million Americans experience low-back pain at any given time.
• One-half of all working Americans admit to having back pain symptoms each year.
• Americans spend at least $50 billion each year on back pain, and that’s just for the more easily identified costs.
• Back pain costs the U.S. about $100 billion each year: 20% in direct costs and 80% in lost productivity.
• In one study, 54% of participants (which translates to 100 million American adults) reported having low back pain that interfered with their daily activities.
• In the same study, 48% of participants thought surgery is the only real cure (even though surgery is appropriate in less than 5% of people with back pain).
• Back pain is one of the most common reasons for missed work. In fact, back pain is the second most common reason for visits to the doctor’s office, outnumbered only by upper-respiratory infections.
• Most cases of back pain are mechanical or non-organic, meaning they are not caused by serious conditions, such as inflammatory arthritis, infection, fracture, or cancer.

References:

• Johns Hopkins White Papers, The Johns Hopkins Medical Institutions, Baltimore, MD, 2003.

• Jensen M, Brant-Zawadzki M, Obuchowski N, et al. Magnetic Resonance Imaging of the Lumbar Spine in People Without Back Pain. N Engl J Med 1994; 331: 69-116.

• Vallfors B. Acute, Subacute and Chronic Low Back Pain: Clinical Symptoms, Absenteeism and Working Environment. Scan J Rehab Med Suppl 1985; 11: 1-98.

• This total represents only the more readily identifiable costs for medical care, workers compensation payments and time lost from work. It does not include costs associated with lost personal income due to acquired physical limitation resulting from a back problem and lost employer productivity due to employee medical absence. In Project Briefs: Back Pain Patient Outcomes Assessment Team (BOAT). In MEDTEP Update, Vol. 1 Issue 1, Agency for Health Care Policy and Research, Rockville, MD, Summer 1994.

• American Chiropractic Association