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Unlocking the Secrets of the Pelvis Part 1

Unlocking the Secrets of the Pelvis Part 1

Treatment of pelvic dysfunction that is effective and lasts just beyond our patients walking out to the parking lot to where their car is parked requires observing and thinking about tri-planer movement of the pelvis.

To understand balanced and symmetrical movement of the pelvis we need to understand “myokinematics” or the study of motion produced by specific neuromuscular forces.(1 ) The pelvis, as well as our entire body, needs to have as close to symmetrical muscle flexibility, strength and length as possible. Asymmetries in muscle strength, length and endurance with agonists and antagonists can eventually create dysfunction in movement and alignment patterns. Our rehabilitative goals need to include addressing these asymmetries effectively. (1)

We are born with asymmetries that the body usually deals with effectively for the most part but does need our help when those asymmetries form dysfunctional myokinematic patterns that lead to pain, decreased performance and ultimately premature degenerative changes.

Lets explore some of the many asymmetries that we as humans possess and need to integrate and balance every minute of every day. For starters, we have a left and right sided portion of our brain with the left side being associated with motor skills and analytical thought while the right side more with abstract thought and creativity. The autonomic nervous system with sympathetic and parasympathetic portions can often be out of balance and asymmetrical. Would you agree that in this day and age, there is too much stimulation or “tone” on the sympathetic or fight or flight side? The lymph system is asymmetrical with drainage on the right side clearing the right arm and chest and the rest of the body being drained on the left. Most of us are right hand dominate over the left and if you take a picture of your face, split it in half, use a mirror image and combine right to right and left to left side and you may not recognize yourself!

One of the most significant asymmetries our bodies has to integrate is with the diaphragm or “Big D” and respiration is key when considering effective treatment of musculoskeletal function .

There are two leaflets of the diaphragm with the right side having bigger and more muscular “crura”. The left side is smaller and has less muscular crura and attaches 1 to a1 ½ half lumbar vertebra higher than the right. On the right side of the abdominal cavity is the liver which helps “dome” the diaphragm on that side. There are also three lobes of lung on the right side as opposed to two lobes on the left with the heart and aorta orienting more towards the left. To help balance this asymmetry is a small muscle in the anterior chest wall called the transversus thoracis or triangularis sterni. (2)

The diaphragm may be the most important muscle in the body. Obviously it is the key muscle for breathing but it also must stabilize the lumbar spine and torso as well. Breathing, stabilizing and even walking are just some of the functions connected to Big “D”. Typically the left side of the chest wall “flares” because of inactivation of the anterior lateral abdominal muscles together with a flat or over-activated diaphragm on the left side. Remember, it doesn’t dome like the right side does and full exhalation does not commonly occur on our left side unless we are trained to do so.

The inability to exhale completely and coordinate the diaphragm with the abdominal wall results in a faulty “Zone of Apposition”(ZOA) that results in pelvic misalignment as well as thoracic misalignment. (Please refer to my article: Robert “Skip” George, D.C. Part 3 of Breathe Well and Breathe Often, Dynamic Chiropractic, Sep. 9, 2012 ) This connection and potential asymmetry of the diaphragm has a profound effect on alignment of the lumbar spine!

Understanding ZOA is fundamental to the understanding the close relationship with the diaphragm as well as the sequence of muscles that create a “polyarticular chain” that effects all neuromuscular skeletal movement and function.

To understand pelvic dysfunction and how to restore balanced biomechanics, we need to look at groups of interconnected muscles and how they interact in three planes of movement. Ron Hruska, MPA, PT and director of Postural Restoration Institute, describes the “Anterior Interior Chain (AIC)” composed of muscles that form a polyarticular connection starting with attachments to the costal cartilage and bone of rib 7 through 12 then terminating at the lateral patella, head of the fibula and lateral condyle of the tibia. These two tracts of muscles, left and right side, are comprised of the diaphragm to psoas muscle then with the illiacus, TFL, biceps femoris and vastus lateralis combining a chain of muscles that have significant influence on balanced pelvic motion, breathing and gait.(3)

(This left and right AIC has a profound effect on another polyarticular set of muscles called the brachial chain and will be described in a future article.)

“Tone”, either too much or too little, can have a profound influence on an asymmetry and whether or not that asymmetry will affect us in terms of function, athletic performance or chronic pain in the spine, pelvis or an extremity. It is important to remember that asymmetries, anatomical or neurological, are not usually a problem or issue because our bodies have a system of homeostasis that help us adapt, balance and adjust to those asymmetries. It is only when those asymmetries become too excessive and we are unable to restore balance that they are a problem. One of the goals, as James Anderson states in the Myokinematic Course, is that these patients with too much tone just want to relax!

The side that usually has too much tone for most human beings is the left anterior interior chain unless you are born with liver and three lobes of lung on the left side. (“Situs Inversus” is a condition where the organs are flip flopped on opposite side and is rare.) The reasons for this are many but lets just start with the diaphragm being flatter or less domed than the right side. Remember when the diaphragm contracts, the central tendon drops and the diaphragm flattens to create negative pressure in the chest cavity so the lungs fill with air. Typically, most people have a dominate left anterior chain pattern because if the diaphragm doesn’t completely relax, neither will the rest of those muscles mentioned in the left polyarticular chain. (In fact, the muscle fibers of the diaphragm and the psoas are so closely interrelated that upon dissection it is nearly impossible to distinguish between the two.) (3)

This excess tone or inability to relax the left anterior chain of muscles has many consequences anatomically. Typically there is an “orientation” of the sacral region pelvic to the right with an anterior tilt and flexion of the hip on the left side if you are viewing from above in the transverse plane. In addition, with the above mentioned rib flare especially on the left, the thorax tends to rotate to the left creating the opportunity for scoliosis, rotational/compressive forces to the discs and excessive stress to the facet joints of the thoraco/lumbar spine because of a rotational/extension alignment and movement pattern. (1)

In Part 2 of “Secrets of the Pelvis” I will be describing specific muscles and the myokinematic pelvic patterns they influence. I will also describe the importance of the diaphragm and breathing with every one of our patients. And ultimately in this series on the pelvis I will describe corrective treatment strategies that help evolve our patients from purely passive and dependent care to being a more active and independent participant in their well being!


1. Myokinematic Restoration, Postural Restoration Institute, Home Study Course, Pg. 1, Pg. 8

2. Postural Respiration Seminar Notes Pg. 11, May 18-19, 2012 James Anderson, MPT, PRC

3. Postural Respiration Lecture Notes May 18-19, 2012, Brachial Chain and Anterior Interior Chain- Pg. vi, The Left Anterior Chain Pattern- Pg. vii, Zone of Apposition, Ron Hruska, MPA, PT -Pg.viii


Dr. Robert “Skip” George owns La Jolla Sport and Spine in La Jolla, CA where he integrates chiropractic, rehabilitation and sport performance training. He has lectured nationally on prevention and treatment of sports injuries as well as coaching chiropractors on how to evolve their practices to adapt to rapidly occurring changes in the healthcare system. He is also an instructor for the Functional Movement Screen (FMS) and can be reached at