The synergy of proper posture and an ergonomic chair will ensure a long, healthy career as a dental hygienist.
by Sandra Nagel Beebe, RDH, MSEd
I still remember the admonishment of my first grade teacher. "Sit up straight. Young ladies and gentlemen need good posture to succeed." I would quickly sit up, back erect, and feet flat on the floor. Within minutes though, I would begin to slouch down in my seat into what I thought was a comfortable position until the next time we were warned to "sit up straight!"
It was not until I was older that I realized how important posture would be to my success and health as a dental hygienist. Proper posture is a learned behavior — it is not automatic. John Dewey observed, "It is as reasonable to expect a fire to go out when it is ordered to stop burning as to suppose that a man can stand straight in consequence of a direct action of thought and desire."
Contrary to what my first grade teacher told us, good posture is not sitting with shoulders thrust back, chin jutting forward and your back rigidly straight. Instead, it is the positioning of your body parts relative to one another. Your posture constantly changes as you move during your activities, but by having your ears over your shoulders, your shoulders over your hips, and your buttocks resting against the back of the chair your body will be balanced.
Unfortunately, as Dewey alluded, your posture is second nature to you. It is a habit and normally you do not even think about it and others may be more aware of it than you. You may be aware of headaches, backaches, and fatigue, but will probably not associate any of them with your posture. They are, however, the body's warning signs of poor posture and are the indicators of worse things to come. Posture has a direct affect on your nervous system, and research suggests poor posture can affect headache frequency, blood pressure, back pain, mood, energy level, and digestion. Poor posture stresses joints, ligaments, and muscles, eventually leading to back and neck pain. It can cause crowding of the heart, lungs, and abdominal organs, impairing their function. It distributes uneven stress on spinal joints and discs and may result in permanent damage. To better understand why posture is a critical element to your success, let me briefly describe the anatomy of your lower back.
If you look in a mirror while standing, your lower back curves slightly. This curve, or lordosis, helps distribute your weight through the spine and pelvis. Discs are the structures which serve as shock absorbers among the 24 vertebrae of your spinal column. The center of the disc, called the nucleus, is soft and springy and accepts the shock of standing, walking, running, sitting, and moving. The outer part of the disc is composed of a series of interwoven layers of fibrous tissues, which hold the nucleus in place and provides structure and strength to the disc.
As you sit, your pelvis rotates and the lordosis is flattened. Poor posture builds pressure in the discs, causing damage and muscle strain, particularly of the spinal muscles. The first warning signs are backaches, neck pains, and chronic fatigue. Continued poor posture and other stresses can cause the nucleus tissue to be placed under so much pressure that the annulus herniates or ruptures. When a disc herniates, it may be extremely painful to sit, stand, or walk because of the pressure against one or more of the spinal nerves.
Most disc herniation takes place in the lower back or lumbar region of the spine, and the second most common location is the neck or cervical region of the spine. A herniated disc in the lumbar region may send pain shooting down through your buttock and thigh into the back of your leg. Cervical disc herniation may cause pain in the shoulder, arm, and hand. Any herniated disc can cause muscle weakness, make it hard to get up when you have been sitting or lying down, and cause pain when you move or strain, even when you cough or sneeze. Herniation has also been reported to cause pain in the lower right side of the abdomen and affect nerves to the bladder and bowel, causing incontinence.
It is estimated that low-back pain affects 150 million Americans a year, resulting in more than 150 million lost workdays each year. Neck pain may be as frequent as low-back pain, according to a recent study.
The consequences of poor posture can be disastrous to our health and careers. It is never too late to correct your posture. If you are already experiencing any of the symptoms described, you may have disc degeneration. Sitting properly while working may alleviate some of the discomfort. If you have not developed symptoms, following a few simple steps will ensure that you continue pain-free and healthy.
First and most importantly, sit up straight with proper alignment. Do not slouch. A good practice to follow is having one of your colleagues observe you while you are working. They will be able to see deficiencies in your posture and offer suggestions. If they notice you are bending forward and your spine is curved like the letter "C," you need to work on improving your posture until your back is in its natural "S" curve. Be conscious of your posture while attempting to correct problems. If you are not thinking about how you are sitting, your body will quickly revert to old habits.
Secondly, having a chair that adjusts to the proper height will greatly increase your ability to maintain good posture. The height of your seat should be approximately the length of your tibia (the bone in your lower leg between the knee and ankle) so when you sit your knees bend at a 90-degree angle. The seat depth should allow approximately one to three inches of space between your knees and the edge of the chair. The width of the chair should be at least two inches wider than your buttocks so you have adequate support while working. A good chair is one that is referred to as ergonomic. The ergonomic chair will support your upper back (thorax), lower back (lumbar), sitting bones (ischial tuberosities), thigh area, the area behind the knees, and your feet.
A well-designed chair with correct lumbar support ensures that the region from your thorax to your neck is straight and slightly forward. It will provide extra support to your lumbar region and help maintain the natural "S" curve of your spine. A properly contoured seat supports the ischial tuberosities, relieving upward pressure that may distort the tailbone curve, and it enhances support to the thighs. A sloping edge to the seat will increase contact with your thighs, reducing pressure behind the knees and ensuring proper blood circulation. Proper seat height ensures your feet will be flat on the floor and reduce pressure on your knees and feet.
Remember though, no matter how well-designed your chair, if your posture is poor you will still develop problems. Most back injuries are not caused by a single incident, but rather by a combination of poor posture and muscle strain over a period of months or years. Once you break the habit of poor posture you will find yourself feeling more alert, and you will be the picture of health and vigor your patients expect to see when they visit your office.
Sandra Nagel Beebe, RDH, M.S. in Ed., is a clinical instructor in Health Care Professions at Southern Illinois University at Carbondale, Ill., and teaches in the school's dental hygiene program.