Back injuries cause municipalities to spend thousands of dollars each year for medical treatment of workers or for permanent disability. Delivery of public services are also adversely affected by injured or absent workers.
In order to avoid back injuries and maintain a healthy back, one must understand the components of the back and their functions.
The Parts of the Back
The spine is the primary component of the back. It supports the head and trunk, gives flexibility to the body and protects the spinal cord. Small bones called vertebrae form the spine. The five types of vertebrae have unique forms suited to their locations and functions.
There are seven cervical vertebrae supporting the skull and neck. They tend to be smaller and more flexible than the other vertebrae. The chest cavity is formed by 24 ribs extending from the twelve thoracic vertebrae. The five lumbar vertebrae are the largest and carry most of the body’s weight.
Below the lumbar vertebrae is the sacrum, a single bone consisting of five fused vertebrae. At the base of the spine is the coccyx, or tailbone, which is also formed by fused vertebrae.
In between the vertebrae are shock absorbers called discs. Discs have a strong outer casing with a pliable jelly-like substance inside. The top and bottom of the disc is attached to the vertebrae. Although you often hear of a “slipped disc,” discs cannot slip out of place.
When a disc is damaged, the jelly-like substance may protrude from between the vertebrae, creating the impression that a disc has moved.
The spinal cord, with the brain, forms the central nervous system. It is approximately 18 inches long and one-half inch thick. The vertebrae form a canal through which it runs. 31 pairs of nerves branch out from the spinal cord and travel throughout the body. These nerves carry commands to the organs and muscles and relay messages relating to touch, temperature and pain.
Approximately 400 muscles work together to stabilize the spine, maintain proper posture and allow movement. More than 1,000 tendons connect these muscles to the bones.
Ligaments are bands of tissue between the bones that maintain the spine’s alignment. They prevent damage due to excessive movement.
Even minor damage to any one component of the back’s structure can upset the balance and make movement painful. Back pain can occur for no apparent reason and at any point on the spine. However, the most common site for pain is the lower back because it bears more than half of the total body weight.
Lack of muscle tone and excess weight, especially around the middle, commonly cause and aggravate back pain. Poor posture adds stress, too. When slouching or standing with a swayback, the back’s natural curves are exaggerated. Any imbalance can stress muscles and joints, causing fatigue and injury from overuse.
Add the daily stresses put on the back, such as carrying heavy objects, leaning over close handwork for long periods or even applying the brakes on the car, and all too often the result is the familiar complaint, “Oh my aching back!”
Common Types of Back Injuries
Muscle strains and spasms - Aches and pains, once commonly called “lumbago”, usually signal strained muscles, tendons or ligaments or inflamed joints along the backbone.
If you strain your back, you may feel pain immediately or develop soreness or stiffness later. Muscle spasm may occur after a back injury. Spasm is your back’s response to an injury. It’s designed to immobilize you and prevent further damage.
Osteoarthritis - Commonly referred to as arthritis, this disorder affects a majority people over the age of 60. Overloading, injury and aging can slowly deteriorate cartilage, the protective tissue that covers the surface of vertebral joints. Discs between vertebrae become worn and the spaces between the bones narrow. Bony outgrowths called spurs also develop. Gradually the spine stiffens and loses flexibility.
As vertebral joints rub together with greater force than normal, the surfaces where they meet, called facets, compress and become irregular. Cartilage becomes worn and the result may be pain.
Sciatica - About 10 people in 100 with back pain may experience “sciatica”, named after the sciatic nerve that extends down each leg from the hip to the heel. Nerve inflammation or compression of nerves in the lower back can cause sciatica. Pain radiates from the back down through the buttock and to the lower leg.
Tingling, numbness or muscle weakness may also accompany nerve compression. Coughing sneezing or other activities that exert pressure on the spine can worsen sciatica. Usually the pain resolves on its own. However, severe nerve compression can cause progressive muscle weakness.
Herniated disc - A “slipped disc” is commonly used to describe this condition. While they don’t actually “slip”, normal wear and tear or strain may cause a disc to bulge or rupture.
When a disc herniates, parts of the disc can protrude from their normal position between the vertebrae. Pain can result when a fragment of the herniated disc places pressure on an adjacent nerve.
Common Causes of Stress to the Spine
Gravity is the most troublesome, constant source of strain on the body. It affects the body in a variety of ways in different positions.
Standing
Gravity forces low back arch to increase which leads to strain on joints and ligaments.
Gravity is worse when reaching overhead or when lifting, pushing or pulling overhead.
Stress worsens when muscles fatigue with pro- longed standing.
Sitting
Unless the spine is well supported, gravity forces it to “flex” or slouch, as in curling knees to chest, squeezes discs in front and stretches ligaments in rear of spine.
Worse in soft, low couches or chairs.
Worse when leaning forward over work or desk.
Bending while standing or sitting
Gravity forces spine to curve forward or flex, compressing spinal discs and stretching ligaments.
Made worse when arms are extended forward.
Made worse when holding or lifting objects.
Ways of controlling stress to the spine
Rest gives the body a chance to heal and repair itself. Resting the spine can be done in several ways.
Temporary rest periods: 1-20 minutes during activity, every one to two hours as activity permits.
Contour position; This position involves lying on a firm surface on the back with hips and knees bent to 90 degrees with the lower legs and feet supported on a chair or similar object.
Leaning against a wall gives a brief rest while standing or is used as an alternative to sitting. The back should be positioned against a wall with the buttocks and lower back flat against the wall. The buttocks should be tucked under for pelvic tilt. The feet should be placed forward approximately 12 to 24 inches from the wall with the knees relaxed or slightly bent. The feet should be comfortably apart and if desired, hands can be placed behind hips.
Propping up a foot is used to relax the spine while standing. Elevate one foot onto an object 6 to 18 inches high, depending on personal comfort. Frequently alternate the elevated foot with the one on the floor. The pelvis should be tilted with elbow or hand braced on the flexed leg if possible.
Sleeping
Lying on the back with a small comfortable pillow under the head is a good resting position. Knees should be bent with one or two pillows under the knees.
When lying on side, a moderate sized pillow should be used under the head and neck, not under the shoulders. The head and neck should be kept in a straight line with the trunk of the body. Hips and knees should be bent comfortably with the knees drawn slightly toward the chest. A pillow be- tween the knees also relieves lower back strain.
Sleeping on the stomach increases strain to the lower back, neck and jaw.
Good posture
Good posture means keeping the body well- balanced and supported with the natural amount of curve in the lower and upper back and neck. Good posture avoids extreme swayback or bending of the spine for any period of time.
Body mechanics
During activity, movement and pressure cause the spine to wear out or become tired. Good body mechanics uses the body in ways which cause the least wear and tear on the body, especially the spine.
Reaching overhead causes increased swayback. When reaching overhead, one should keep knees “unlocked” or slightly bent; use a stable broad base of support (legs and feet spread approximately hip or shoulder width apart), and use a stool or ladder for close approach and to prevent “over-reaching”.
Reaching in front of or away from body should be minimized if possible. The upper body, elbow or forearm should be braced for additional support. Knees can be braced against a sturdy object for improved support.
Pushing or pulling causes many injuries. Pushing is usually preferred over pulling, but will depend on the situation. Mechanical assistance such as dollies, forklifts, etc. should be used where available. Objects weighing over 30 pounds should be lifted, pushed or pulled by two persons whenever possible.
When bending, use a half kneeling or squatting position for low work. Support the upper body by supporting the trunk or leaning on a hand, elbow or outstretched arm. A broad base of support should be used. When bending for extended periods of time, change positions often.
Improper lifting or carrying of objects causes a large number of injuries to municipal workers. Important points to remember are to avoid extremes of forward bending or swayback during lifting and to keep objects as close to the body’s center of gravity as possible. The following points should be kept in mind.
Plan the lifting movement:
Size up the load.
Assess the need for another person’s help or mechanical assistance. (When in doubt, ask for help!)
Talk over the situation with helpers.
Move close to the object.
Keep a wide stance with feet spread shoulder width apart and one foot placed slightly forward of the other.
Bend with the legs. Get down low for low objects, squat or kneel in a half kneeling position, bring object between knees and avoid lifting objects out over the knees.
Keep the back straight with shoulders back, buttocks out and knees bent.
Bring the load close to stomach. Get control of the load before standing and brace the object against the thigh.
Stand smoothly. Jerky movements may cause sudden strain. Use leg power and keep back straight.
Pivot rather than twisting at waist. The lift should be completed before attempting to change direction of movement. Take a step with the lead foot in the direction you wish to move. Turn the whole body as a unit and avoid crossing the feet.
When setting objects down, simply reverse the procedures used in lifting. Move close to destination before bending. The load should be braced against the stomach or thigh.
The principles outlined above may be difficult to apply in all situations, but if applied whenever possible to routine situations they will become good habits to reduce spinal stress.
It is important for employees to practice these principles with critique and supervision, since body awareness must be developed. Years of using improper lifting techniques cannot be overcome in one easy session. Constant attention must be paid to proper lifting techniques before injury rates can go down.
Avoiding Back Injuries was written by Gary Cauthen, OMAG Loss Control Specialist. You may contact the author at: gcauthen@omag.org. The information in this bulletin is intended solely for general informational purposes and should not be construed as or used as a substitute for legal advice or legal opinion with respect to specific situations, since such advice requires an evaluation of precise factual circumstances by an attorney. The Oklahoma Municipal Assurance Group does not represent or endorse any group, site or product mentioned in the article.
