Subtle progressions that reduce the quality of our clients' lives and contribute to many of our clients' chronic somatic problems continues as a theme for this column. Thomas Walsh, DDS offers his 33 years of clinical experience as a general dentist and extensive orthodontics training to bring to light the progression of airway obstruction.

Air is one of our greatest needs for survival as human beings. The "airway is the tube" through which we breathe. It begins at the opening of the nostrils and continues all the way to the lungs. Visualize this tube as the snorkel through which we breathe. The diameter, shape and volume of this tube regulates the rate of exchange between oxygen entering the lungs and the exiting of carbon dioxide out of the lungs. A large diameter airway encourages an easy passage of air whereas a small diameter airway generates a greater resistance to airflow in both directions.

This essential airway tube is formed in utero and continues to develop from infancy until the teenage years. The airway is comprised of multiple spaces including the: nasal chamber; sinuses; and the upper, middle and lower pharynx. In normal growth, these chambers need to form in proportion to the size of the individual. That is to say that one needs a tube to breathe through that is large enough in diameter to support respiration during sleep and daily activity. The genetic design (preprogrammed in our DNA) mediates the enlargement of the bones, muscles, connective tissue etc., of our face and throat, to provide room for these spaces of the airway.¹

Unfortunately, many times this airway tube does not form properly. A malformed airway can wreak havoc with muscle tone and head position. Research has clearly correlated head posture with mandibular position and temporomandibular joint disorders.^2-7 Many of your clients will likely have these problems. They may complain of pain in the following muscles: masseters, sternocleidomastoid muscles (SCMs), trapezius, scalenes, splenius capitis and cervicis, medial and lateral pterygoids, temporalis and even the muscles of the low back. Simply put, if an airway is obstructed, a person will instinctively modify their muscle function to optimize or open the airway. This postulation reflects the essence of the Inside-Out Paradigm.

Clients rarely sense that they have a problem with their airway. (Dr. Walsh: "After 33 years of practicing dentistry, not one growing child or adult client has ever reported to me that they have a small airway.") The development of the airway is controlled by the autonomic nervous system of the growing child. Nature (your biologic engineer) detects this progressively developing constriction in the airway and makes alternate plans involving compensatory patterns of the musculoskeletal system.

For example, if the constriction is in the nasal cavity, the growing child will start to breathe through the mouth instead of the nose. The muscles of the face will pull open on the lower jaw, the mandible, and redirect the growth of this mandible to a more vertical or open position.⁸ If the airway obstruction occurs in the middle to lower oral pharynx (throat) the individual will likely extend their head forward to help open this airway tube.^9-11 Again, this occurs without any conscious awareness within the individual. The head has now extended forward beyond the normal plane of vertical posture.

Forward head posture is very common and easily misunderstood. It is the opinion of these authors that many cases of forward head posture relate back to early childhood airway disorders, and improper muscle function of the oral cavity and have been clinically correlated to a congenitally short or an emotionally reactive esophagus.¹²

That being said, it is very difficult to separate the primary cause or etiology. We have the case of the proverbial chicken and the egg scenario, i.e., which came first? For some individuals the muscle function was altered first and in other children the airway obstruction occurred first.

There are many contributors to airway obstruction. Common influences include the following: improper swallowing habits developed from bottle nursing, air pollutants, food allergies, junk foods, broken nose, deviated septum, improper growth of the jaws (the maxilla and mandible), improper tooth position, imbalanced facial muscles, oral habits such as thumb sucking and many more. The thread that links all of these issues to you and your practice tends to be the compensatory forward head posture and associated muscle pain.

Feel this. Your head weighs about 12 pounds much like a bowling ball. Imagine if we placed a stick inside the hole of the bowling ball. Supporting this ball would not be difficult assuming the stick were directly under the bowling ball. Now, let's extend the bowling ball (your head) out beyond the stick (your spine) at a 45-degree angle. Suddenly the force on your spine from your head is dramatically increased. Forward head posture associated with airway obstructions places your neck and shoulders at a leverage disadvantage. It is reasonable to expect cervical bone remodeling and muscle pain to occur over time.

Airway obstructions and improper oral muscle balance commencing near infancy or in a growing individual have been linked to many systemic disorders later in life. These include the following: dental malocclusions, TMJ joint disorders, distorted faces, obstructive sleep apnea in children and adults, bed wetting, migraine like headaches, neck and back pain, lower IQ, stunted growth, criminal behavior tendencies, heart damage and increased risk of heart attack, arteriosclerosis and atherosclerosis, stroke, acid reflux and digestive disorders, anxiety and depression associated with lack of proper REM sleep, increased risk of occupational accidents and the list goes on.^13-18

The following images graphically display the difference between normal and obstructed airways. These images have been acquired through cone beam imaging technology similar to CT scanning but with dramatically reduced radiation exposure as part of a comprehensive dental examination to evaluate patients for temporomandibular joint, orthodontic and sleep disorders. Figure 1 depicts the size and shape of a normal airway from a side view (coronal) and figure 2 from a cross-sectioned view looking downward (transverse). Notice the area identified by the pointer. Figures 3 and 4 demonstrate the reduced airway from both a coronal and transverse view. Note the constriction of the airway.

The diameter of the constricted airway is equivalent to the diameter of drinking through a straw. "Imagine the experience of breathing through a straw" all day. This client was completely unaware of any obstruction in the airway yet suffered from many clinical symptoms including lack of sleep, grinding of their teeth, pain and spasms in the neck and shoulders.

In summary, many of our clients suffer from airway obstructions that progress and worsen through life. As massage therapists we see many individuals with underlying problems as have been described here. Clients with head and neck pain including forward head posture are likely to have airway obstructions and are at risk for obstructive sleep apnea, a known contributor to decreased quality of life and reduced longevity. Your sharp observations can actually save lives.

References

1. Enlow DH, Hans MG. Essentials of Facial Growth. Philadelphia: W.B. Saunders, 1996.
2. Sakaguchi K, et al. Examination of the relationship between mandibular position and body posture. J Craniomandib Pract, 2007;25:237-48.
3. Bracco P, Deregibus A, Piscetta R, Ferrario G. Observations on the correlation between posture and jaw position: a pilot study. J Craniomand Pract, 1998:16:252-8.
4. Makofsky HW. The influence of forward head posture on dental occlusion. J Craniomandib Pract, 2000;18:30-9.
5. Makofsky HW, Sexton TR. The effect of craniovertebral fusion on occlusion. J Craniomandib Pract, 1994;12:38-46.
6. Bazotti L. Mandible position and head posture: electromyography of sternocleidomastoids. J Craniomandib Pract, 1998;16:100-8.
7. Clark GT, Browne PA, Nakano M, Yang Q. Co-activation of Sternocleidomastoid muscles during maximum clenching. J Dent Res, 1993;72:1499-1502.
8. Harvold EP. The role of function in the etiology and treatment of malocclusion. Am J Orthod, 1979;54:883-98.
9. Linder-Aaronson S, Woodside DG. Excess Face Height Malocclusion: Etiology, Diagnosis and Treatment. Chicago: Quintessence Publishing Co., 2000.
10. Hellsing E. Changes in the pharyngeal airway in relation to extension of the head. Eur J Orthod, 1989;11:286-94.
11. Solow B, Skov S, Ovensen J, Norup P, Wildschiodtz G. Airway dimensions and head posture in obstructive sleep apnoea Eur J Orthod, 1996;18:571-9.
12. Alexander DG. "Part IV: Chronic Problems Related to Gall Bladder Dysfunction/Disease." Massage Today, January 2008;8(1), and "The Progression of Cervical Stenosis toward Cervical Spondylotic Myelopathy." Massage Today, April 2008;8(4).
13. Woodside DG, Linder-Aaronson S. Relationship between mandibular incisor crowding and nasal mucosal swelling. Proc Finn Dent Soc, 1991;87:127-38.
14. Jordan AS, McEvoy RD. Gender differences in sleep apnea: epidemiology, clinical presentation and pathogenic mechanisms. Sleep Med Rev, 2003;7:377-89.
15. Baldwin CM, Bootzin RR, Schwenke DC, Quan SF. Antioxidant nutrient intake and supplements as potential moderators of cognitive decline and cardiovascular disease in obstructive sleep apnea. Sleep Med Rev, 2005;9:459-76.
16. Baldwin CM, Bell IR, Guerra S, Quan SF. Obstructive Sleep Apnea and Ischemic Heart Disease in Southwest U.S. Veterans: Implications for Clinical Practice. Sleep Breathing, 2005;9:111-8.
17. Archbold KH, Pituch KJ, Panahi P, Chervin RD. Symptoms of sleep disturbances among children at two general pediatric clinics J Pediatr, 2002;140:97-102; and Mulvaney SA, Goodwin JL, Morgan WJ. Rosen GR, Quan SF, Kaemingk KL. Behavior problems associated with sleep disordered breathing in school-aged children the Tuscon Children's Assessment of Sleep Apnea Study. J Pediatr Psychol, 2005;31(3):322-30.
18. Gozal D. Sleep-disordered breathing and school performance in children. Pediatrics, 1998;102(3 Pt 1):616-20.