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 of 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.
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.
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.
Ways of controlling stress to the spine
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 the hips.
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 relieve lower back strain.
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 people 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.
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.
