Muskuloskeletal Disorders in the Workplace
by Hayley Kotton, LMT
The advancement of technology has brought with it a crop of muskuloskeletal disorders (MSDs) in the work place. Here I will focus mainly on the role of head placement in posture and how it can help prevent MSDs.
While sitting at the computer the neck should be balanced over your shoulders and in line with the torso. When these are not in balance the body slouches. Sitting slumped for hours at a time, reduces the lumbar spinal curve and increases pressure on the low back, stressing the discs and posterior ligaments, and increasing the risk of pain and stress to lower and upper back as well as the neck. Unbalanced sitting posture has been found to be a major factor in thoracic outlet syndrome and carpal tunnel syndrome. In addition, while slouching, your abdominal diaphragm is severely restricted making it hard to breath normally. From this position it is even harder to raise your hands to keyboard height.
An interesting change takes place within the body while slouching. In this position the body is away from its midline. Changes take place to re-center the body which continually strives and adapts to maintain its center. The superficial abdominal muscle or rectus abdominus becomes tight in order to hold the torso in its forward slump. This muscle interdigitates with the chest or pectoralis major muscle causing them to also become tense pulling the upper torso forward and enlisting the shoulders to round and complete the slouch. While the body is forming this adaptive ìcî shape the head comes forward or protracts. You can experience this by sitting and tucking your pelvis, the body moves backwards into a ìcî shape while the head moves forward exaggerating the cervical spinal curve. At this point the jawbone or mandible is only movable bone that can react to this forward motion and bring the body back to center. This causes a host of problems and can be linked to Temporomandibular Joint Disorder (TMJD).
Head position is important in relation to your monitor.. The placement of the monitor dictates where your head will rest. If the monitor is too high or too low, your head will tilt back, or forward for prolonged periods, thus fatiguing neck and shoulder muscles. It is preferable to have the top of the monitor at eye level or just below. It should be no more than 35-degrees off in any direction.
Ideally, full body computer posture should look as follows. Sit with both legs and arms each at 90-degree angles and both feet on the floor or on a footrest. Elbows hang at your side while also supported. If the angle is less than 90-degrees the work surface is too high, shoulders are raised and tense. Hands, wrists, and arms are in line with one another with no bending of arm or wrist. This prevents stress of tendons and their sheaths, which could lead to irritation, and fraying of the soft tissue. It is also important not to stress the tendons, tendon sheaths or muscles in the hands or wrists. Therefore when using a mouse move out of your shoulder and arm not out of the wrist. Shoulders are relaxed, low back supported. If your chair doesn't have a lumbar roll a rolled towel works as well. Keep items you are working with close. Including the mouse, books, and documents to name a few. Close distance allows you to avoid reaching which raises shoulders, fatiguing both arms and shoulders.
Often I see clients for carpel tunnel and other nerve impingement problems. Part of the treatment involves releasing the groups of muscle dysfunction outlined above. Releasing the rectus abdominus (abdominal), pectoralis major and minor (chest), lumbar area, and neck muscles, especially the scalene group, and the jawbone, goes along way to relieving discomfort and undoing the slouched posture. The above ergonomic guidelines are a good preventative measure to avoid MSDs. Granted these changes can be hard to make but worth the while.
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