The following articles are examples of  "thinking anatomy": thinking through the implications of 

the structure (anatomy) and function (physiology) of the tissues involved.


Assessment, Then Diagnosis,  by David Zulak MA, RMT

(The Registered Massage Therapists Association of Ontario - RMTAO – changed the title for publication to “Comparing Assessment and Diagnosis”; see: Massage Therapy Today, Spring 2020 p.20-22)

 Assessment is an essential part of our scope of practice; it is the perfect tool for our work. We assess because assessment provides us the understanding we need in order to treat the specific patient in front of us. Diagnosis allows designated medical professions to provide their prescribed treatment to everyone with a specific pathology.

As massage therapists we focus one the specific person on our table. We need to map out their impairments and develop a treatment plan to address their specific issues and needs. That is what assessment is. We do not need to determine a pathology, though we need to know how one may impact our treatment, or to know the red-flags that require us to refer out to a physician. A massage therapist carries out the task of assessing soft tissue and joint injury, without making a diagnosis.

 Assessment, then Diagnosis

Assessment and diagnosis are on a continuum. They are part of the same process. As massage therapists we assess because that provides us the information we require in order to treat. We do not need to diagnose in order to carry out our treatment plan.

Assessment is measuring and observing so that we gather as much information as possible in order to be able to make certain informed treatment decisions. For example, within our scope of practice as massage therapists, our assessment leads us to the following suspicions:

1)    About how this person’s musculoskeletal impairments may have come about.

2)    How the impairments are affecting the person (physically, as well as socially and psychologically.

3)    How to design a plan of care – propose a treatment with specific goals and provide a prognosis, an estimate of how long it will take to reach those goals. This belongs intrinsically to what is called assessment.

 Now, I used the word “suspicions” here deliberately. They are similar to judgements, but are to be understood as hypothetical possibilities, if you like. They help us make decisions on how to proceed and give us certain expectations about what may result. However, “suspicions” also implies that we need to be ready to change our mind about what is going on in light of the results of treatment or changes to symptoms. “Suspicions” implies the necessity to see assessment as an ongoing activity within the treatment process rather than a one-time event that takes place when the client is first seen.

On the other hand, diagnosis, in giving a name to a pathology, conveys the idea of having a definitive understanding of the (universal) nature of such a pathology. It is a nominative judgement arrived at after performing an assessment. In other words, after examining an individual’s particular presentation of their complaint(s) one judges the issue to fall under a specific category of conditions or syndromes. Therefore, a diagnosis does not stand in place of an assessment. An assessment needs to precede any diagnosis. The diagnosis is a specific type of judgement made after an assessment is completed. To give a diagnosis is a judgement reserved for specific professions such as physicians.

The judgements involved in diagnosis have often been taken to have certainty and are characterized as definitive. Further, upon arriving at a diagnosis there are prescribed treatments for the diagnosing professional to follow. These help circumscribe and protect their specific scope of practice while also defining their obligations under their regulatory legislation. While a diagnosis can certainly be changed, there does tend to be an inherent momentum that may restrict the flexibility of such diagnostic judgements once made. Unfortunately, all too often a treatment has to fail before its associated diagnosis is changed.

Therefore, a diagnosis requires an assessment to happen first. However, an assessment can stand on its own and still support specific judgements (“suspicions”) about how to proceed with treatments and present a prognosis for such treatments.

Assessment, Impairments & Outcomes

Assessment for massage therapists describes the finding of the patient’s specific impairments and seeks outcomes specific to massage therapy treatment. The diagnostic focus on pathologies, conditions and syndromes with prescribed treatment protocols that many other health professionals practice may give us a suggestion of what is at issue but it provides no specific treatment direction for our profession.

Therefore, the purpose of assessment for massage therapists is to be focused on the goals and aims of treatment rather than on categories of pathologies and types of syndromes. The difference between assessing and diagnosing is not merely linguistic; it relates to the very core of our scope of practice as massage therapists.

Briefly, an impairment is a change in the structure or function of the body that is detrimental, (biological, psychological and/or social). An impairment negatively impacts on activities of daily living. As massage therapists our job is to treat the tissues that are impaired (or contribute to the impaired function) of the musculoskeletal system and try to return them to their optimal function. Finally, we re-integrate those tissues and structures back into the whole organisation of the physical person.  A successful treatment is measured by achieving the specific goal(s) for that specific patient.  Ideally, the whole purpose and intent of clinical assessment for a massage therapist is to find, whenever possible, the tissue or tissues involved in the impairment and gather information about the acuity so that impairment is treated  directly and effectively as possible. Even without a diagnosis, by treating the patient’s impairment(s) we will be moving the patient towards healing. In fact, we never do treat a rotator cuff tear per se; rather, we treat the specific tissues involved in the patient who comes to us with shoulder problems. Therefore, we are not necessarily treating conditions, we are treating tissues!

 In our treatment we need to see for ourselves the state of the tissues and how they and the patient have responded to (compensated for) having an impairment. To achieve specific outcomes, and in the priority that is important to the patient, we need very specific knowledge. This is only achieved through a thorough assessment and is not possible if working only from a diagnosis that a patient received from another health care professional or that the therapist assumes is present.

 Therefore,  we need to do our own testing in order to:

1) Establish the impairments that are specific to the client; and be able to explain to the client what has been found and the possible implications (“suspicions”) they imply.

2) Each impairment found defines a goal or potential outcome. With this knowledge we negotiate with the client  the priorities of each outcome that are important for them to achieve.

3) Be able to choose among various techniques and modalities through which we may achieve such goals and offer to the client options from which a treatment plan can be mutually agreed upon.

We now have an assessment and treatment plan for the client that we can confidently say has informed them about the goals and means of treatment and allowed them to come to an informed decision about how they want to proceed. Without assessing for ourselves how can we say that we adequately informed the patient and therefore receive from them an informed consent?

Further, we also must recognize that often the pathology of someone’s pain or dysfunction is never found: no specific diagnosis is ever made by other health care practitioners. This is most clearly seen, for example, in patients presenting with low back pain. The estimates of the cases where a cause of low back pain could be identified range from 10 to 20 per cent. (Hertling & Kessler, 2006) Therefore, if we always need to definitively know the cause, or be able to name the condition prior to treating the patient, we would, (more often than not), find ourselves with nothing to do! Or at best, perform some general routine with a few extra minutes on the area troubling the patient and hope it helps. That’s not treatment.

 However, if we look at each symptom as having specific underlying impairments (specific impaired tissue structure and/or functions) to specific tissues that present as pain, reduced function, restrictions in motion, loss of strength, and the like, then we can almost always find ways to address them. Even when treating some of our most difficult cases we can always find some way to help, (even if it appears at the time to be in a limited way). We have some potential benefit to offer. Further, as we deal with some impairments like pain and/or restriction of motion, the underlying causes often become more apparent as we progress through treatments.

Even if the cause remains elusive, our assessment skills can provide us with a list of impairments that we may be able to address across a spectrum of outcomes: from resolution, to improving function slightly or at least maintaining it, or providing pain management. Even when we have only limited goals of treatment they are clear and we will be able to communicate these clearly to the patient.

Our own assessment allows us to do the measurements which let us to draw up a detailed map of what ails our patient. We describe their signs and symptoms. We observe, measure, evaluate and generate suspicions. This information helps us draw a map that allows us to chart, with our patient, the course of actions to take and so address the outcomes we hope to achieve through an individualized course of treatments. It allows us to not be chained to a specific protocol for a condition, but address the issues of this client before us right now.


Assessment is the tool we need to treat the patient in front of us.  Assessment empowers massage therapists when dealing with the musculoskeletal disorders and impairments that we confront in our daily clinical practice. It makes for a more adaptive approach to treatments, where we are capable of incorporating new information gathered from the tissues and the client’s response to treatment as it proceeds and we can modify our approach accordingly. Trying to stick to a specific diagnosis, to a “condition”  creates the risk of overlooking what is unique in each client’s case, losing that adaptative quality, and being dragged along with the momentum of a prescriptive treatment protocol.


I wrote 15 articles for Massage Therapy Canada Magazine ( in a regular column called "Essentials of Assessment." The column ran regularly, in this quarterly magazine, from the first issue, May 2003 till mid 2007, with only the occasional contribution after that. In 2007 I began to devote all my time outside of my busy clinical practice to writing my text book. [Click on the Text Book tab at the top of the page.] Many of my articles can be found on the Massage Therapy Canada website, where the new publishers have generously posted  articles, for free viewing, from past issues - so far, from Spring 2006 to the present.  (,com_pastissues/Itemid,99/)

This is but one example of many showing Massage Therapy Canada's huge support for the profession of massage therapy.  


Article reprints:

The first three articles reproduced here are examples of thinking osteopathically about treating a client- and were meant for the general public: They were published in a local health magazine in Brantford, ON Canada, where I practice.

- “Migraines can be a pain in the neck, 

- "Why does one hurt being at a desk all day?’"  

- “Has low-back pain taken the spring out of your step?”


The fourth, and final article, was written for massage therapists - “Spinal motions: Structure and function.”                       

note: I have made several small changes to the text from the one that appears in Massage Therapy Canada magazine.


Migraines can be a Pain in the Neck.

The original article, in Brant Fit (Brantford, ON, CA) can be found at:
The one here may have some small revisions.

If you get migraines you know how debilitating they are. But what exactly is a migraine? A migraine can be thought of as a chemical interaction between nerves and arteries on the inside of the skull. The nerve  irritates the artery, which in turn causes the artery to secrete chemicals that irritate the nerve. Now we are left with a self-perpetuating cycle of pain that can last for days.

As well as pain you might also feel dizzy, nauseous, be sensitive to light, and have eye pain. You might also have strange visual experiences or smells before the migraine starts.

The nerve involved in migraines is called the trigeminal nerve. It starts at the base of the skull and travels all the way to the forehead. It also sensitizes the lining around the brain, and for those that get migraines  a branch from it runs right beside the artery.

One of the many signs that can come before a migraine is a stiff neck (on one side more than another) and/or a headache at the base of the skull.

In the diagram you can see the numerous muscles that join the upper spine to the skull. The base of the skull sits atop the spine. Between it and the first vertebra there is a joint. Think of the base of the skull as a rocking chair. With this joint the skull can rock on top of the spine, nodding as in nodding your head “Yes”.

There are numerous types of nerves that pass between the base of the skull and the first vertebra of the spine. Some are going into the spinal cord and up into the brain. And many of these go into where that trigeminal nerve starts.

Now, imagine you are sitting at a computer with your face leaning into the screen (as mine is right now!). Your chin juts up and the base of your skull rocks backward. This compresses nerves that come up into your brain, and some arteries that feed the back of the brain, between the base of the skull and the bony first vertebra. This may cause a headache at the base of the skull.

Then there are the suboccipital muscles themselves. As you can see from the drawing they pretty well fill up the space between the base of the skull and the first two vertebrae, like a curtain. Between these muscles and through them pass all of those arteries and nerves (in and out of the spine). So when the tight suboccipital muscles begin to spasm the nerves going in and out of the brain stem get pinched.

What are the consequences?

1. Now the blood flow is not stopped to the base of the brain, but it can definitely be slowed, and enough to cause some people to feel ‘foggy’.

2. The motor nerves coming into the muscles can get irritated as well and cause those shortened suboccipital muscles to spasm and become painful. You end up with a stiff neck and the back of the head is very painful.

3. The sensory nerves etc. can become irritated and send intense and large amounts of information into the brain. This sends an overloaded signal into the base of the trigeminal nerve.

4. Some of these nerves that enter the brain will even run along with the trigeminal nerve.

Let’s take a bus trip on the Trigeminal Line. The trigeminal nerve breaks into three branches. The lowest branch travels off to the inner ear. Here it controls a very special little muscle in the inner ear that controls the tension on the ear drum. The greater the tension on the ear drum the less volume we get from sound. So if this muscle is over activated it will tighten to the degree that the ear feels “plugged”. I have treated a number of clients who believe they have an ear infection, but the doctor keeps telling them the ear is clear and not inflamed. Further, this branch can cause dizziness (even vertigo) and nausea.

Further along the branch line the nerve supplies the muscles that control the jaw. Hence jaw tension can be an effect. In fact neck tension can increase jaw tension, and jaw tension can in turn increase tension in the suboccipital muscles. The temporalis muscle (at the temple) is a muscle that helps work the jaw. If one side of the neck is stiff and the sub-occipitals are only compressing enough on one side, then you get a one sided migraine!

Another branch line travels to the eye, the sinuses, and the forehead.

1) With respect to the eye the sensory part of the nerve receives pain signals from the surface of the eyeball. Further, the motor part of the nerve controls how the pupil opens (dilates) and closes. If this motor signal is not as it should be (too much stimulus from the nerve) then the pupil does not respond to light correctly. This is why you are so sensitive to light and find it painful..

2) Next stop, this nerve bundle goes to the nasal cavity. There is gathers sensory information (smell and pain) and provides motor function to the goblet cells that produce mucus. Over activity of the sensory nerve can generate pain, like a sinus headache! Over active motor nerves will cause the nasal cavity to produce more mucus, making for a runny nose (even though there is no infection)! It can go so far as to affect what you think you are smelling. Often, migraine suffers can have a smell that is part of their aura prior to a migraine.

3) Our last stop on this is at the forehead. The trigeminal nerve (all three branches) is the pathway for sensation from the face. In the case of this branch, this is skin around the upper part of the eye, eyelid, and forehead.

One final point here: Part of the nerves that can become compressed at the base of the skull is from the sympathetic nervous system: the fight or flight response. Hence, stress can create the proverbial tension headache, and also increase the intensity of other types of headaches and migraines.

Therefore, we have found a path from a suboccipital headache that can create dizziness and nausea, decrease hearing (“plugged ear”); create eye pain and aversion to light; sinus pain; and forehead pain, and pain at the side of the head. Sound familiar? Whether we are going to call it a migraine can depend on the intensity of the headaches for that specific person, and especially if it sensitizes the arteries on the inside of the skull. Many specialists require this vascular component to call it a true migraine.

So you can see that there is a direct connection between suboccipital headaches, sinus headaches and migraines. If you can relax these suboccipital muscles you could prevent or reduce migraine pain. One natural approach can be massage therapy.

The treatment plan includes treating the suboccipitals, which can reduce the intensity and frequency of your migraines, and/or chronic (non-infection base) sinus headaches. If your massage therapist can add on a few osteopathic techniques and use alternative positioning (such as side-lying) then the rate of success will exponentially grow. With these additions massage therapist have had some success in even ending a migraine, or at least dramatically decreasing the level of pain and other symptoms even if the migraine persists. If you think of a migraine as a winding up from a small headache to a full blown migraine, then think of the treatment as a way to start unwinding the cycle that sustains a migraine.

Got a headache? Get a massage!


I sit at my desk all day, so why do I hurt?

People might be surprised to hear that for many massage therapists the bulk of our clients work at desks. And most of these people arrive at massage clinics with complaints of headaches, neck pain, shoulder issues, and low back pain. And they often ask: “Why do I hurt so much? It’s not like I am doing anything strenuous.”

Well in fact there a many reasons why those chained to their desks and work-stations hurt and why they feel discomfort and pain more than those who are active throughout the day. To get a general understanding of all of this we need to look at what is happening to the person who is “just sitting there.” This will give us some ideas about what contributes to feeling pain and to the ill health of tissues, and in contrast what contributes to easing pain and promoting health.

One of the main causes of good health or ill health is in the interplay between movement of the body and the movement of fluids within that body. Many people believe that the heart all by itself is sufficient to move blood to where it needs to go and all the way back again, which is not in fact true. By the time the blood makes its way done to the very fine capillaries where oxygen and nutrients can leave and move into the tissues the pressure left from the heart pumping is negligible.

One of the ways tissues are feed and drained is by what has been called the “muscle pump.” The contraction of a muscle helps to move the blood and lymph out of that muscle, and when it relaxes new blood flows in. Also, the harder the muscle works and pumps the faster the blood is expelled and the more that will be drawn in to feed that muscle.

The opposite is also true. The less a muscle works the lower the rate of blood flow through that tissue. If almost no movement occurs for hours the tissue barely gets enough to sustain its health. If you add on top of that a general tension or high tone in the muscle, well then even less gets in and little gets out or recycled. Now imagine the upper back and neck muscles of someone sitting at a computer for hours. They need to be contracting those muscle to hold themselves up-right, but they never really pump – they do not relax and contract rhythmically – they just hold and hold still, choking the tissue causing it to slowly become depleted of energy and nutrients.

Many of the waste products from cells if left too long in the tissue become “toxic.” They become irritants to the cells around about them, interfering with proper cell function. They will also call for an inflammatory response. Further they break down into substances that can directly irritate nerve endings, creating pain and discomfort.

Now, muscles are a bit dumb. If irritated they tend to just tighten up. When this occurs you can see how everything just goes from bad to worse. The person then feels all of this poor tissue health as aches and pains accompanied by tension and stiffness.

When you watch someone at a computer, or doing any focused work at a desk or workstation you may notice that they hardly breathe. This is something we do when we want to help focus our mind, we freeze all bodily actions. This is ok for short periods of time, but as you can imagine oxygen levels will quickly drop if this is sustained. On comes fatigue and lack of focus, so we have a cup of coffee to keep going. It is not long before we are yawning to get more air – after all it is just a way of taking a deep breath!

I have a pet theory: that we instinctively use our “fight or flight” nervous system in order to help sustain our focus. Imagine being in the woods and thinking we hear a bear, we freeze, breathe hardly at all and that shot of adrenalin gives us that heightened mental alertness. With the fight or flight response is a particular posture – head down and forward with the shoulders up. Sound familiar? You can just hear those keyboards quietly tapping along. We actually stress ourselves out in order to keep ourselves wound up so we can keep working.

The whole point of this discussion is to show how lack of movement and improper breathing is often much more injurious to us than is moving too much. Lack of movement is one of the main causes of the aches, pains and tightness. It also contributes to an exhausted body which has few resources to promote well being and  it also compromises our immune system.

Massage helps those who suffer from this type of fatigue, achiness etc. by:

1) Manually moving the fluids and exchanging blood throughout the muscles of the body. Helping them refuel and remove much of the irritants that have been hanging around inflaming the tissue.

2) Breaking down the adhesions that build up in underused muscles while gently stretching them. This helps prepare the person to get up and move with more ease and comfort.

3) Increasing lymphatic flow which helps move the cellular wastes out of the tissue and into the lymph nodes to be removed. And which by the way also helps the body analyze and scour for bacterial or viral infections. Increased lymph flow generally means a quicker immune response.

4) And last but not least massage has been shown to lower cortisol levels in the blood (a sign of stress) and to increase serotonin levels which make us feel relaxed and more alert.

Therefore while your massage therapist may be working on a specific ache or injury, none the less at the same time all these other general health benefits are happening. Further, these overall health benefits increase the body’s stores and resource to help specific problems heal more quickly and completely. And by the way, all of this also explains why you should do those simple exercises your therapist gives you!



Has Low Back Pain Taken The Spring Out of Your Step?

As anyone who has had low back pain will tell you low back pain is very debilitating.  Other than trauma what else causes low back pain?  More often than not it is caused by a slow decline that begins with poor posture, just like your mother warned you.

Poor posture is caused by muscle imbalance.  Some muscles become short and tight while others become long and weak.  With this contrast in muscle strength joints get pulled out of place. At first this might appear as the chin jutting forward, a duck waddle, a pouch in the tummy that never goes away, a hump in the back, or an unusual walk.  People often tell me that they inherited this walk from their mom or dad.  I have a great photo of my wife and her father standing in the exact same pose.  Some weaknesses may be inherited but much of posture is learned.

The spine has a gentle, natural ‘S’ shaped curve.  The spine is not like a stiff column; it is meant to have some give or a slight springing action.  If you stand up straight and take in a deep breath and hold it in your spine will grow longer.  The curve of the spine will flatten out slightly.  As you breathe out  the curves exaggerate and your spine will grow shorter.  This springiness is not just for breathing (as important as that is) it has lots of uses in the body.  When you walk the shock of each step that you take is absorbed a little bit by your ankles and knees but it is largely absorbed by the spring in your low back. If your low back has lost its bounce every step will be a painful jar right up to your head.  Our springy spine helps us bend over and get back up again.

Some of the cushion in your spine is provided by your (intervertebral) disks.  Healthy disks are not hard they are a little squishy so they also provide some of the bounce in your step. 

When the spine works well it works very well. Unfortunately when things go wrong they go very wrong indeed.  The easiest way for the low back to get into trouble is for it too have either too much or too little curve.  In either case the spine won’t spring the way it was intended to.  The most common way for the low back to take on an improper posture is for the hips and pelvis to tip forward or to tip slightly backward from the norm.  Both of these conditions are caused by muscle imbalance.   Most often this muscle imbalance has been learned.  Sometimes it has been learned through occupations such as work or sports, sometimes through the imitation of others.

Let’s look at a common example.  Pretend you sit at a desk in front of a computer all day. By sitting in the chair your hips are bent, flexed. They will slowly get short and tight over time. the same thing is happening in your low back as you lean forward but still try to keep your back straight. On the other hand, your abdominals and glutes are not being used, and they go weak. Now when you stand up your tight leg muscles attached to the front of your hip will pull your hips down and forward.  Your tight back muscle tip the back of your hips up like a wheel barrow.  The muscles that should stop this tipping, your abdominals and your gluts, are too weak to resist.  Because your low back sits on the pelvis the low back tips forward with the pelvis.  The next thing you do is put both fists in your low back and try to bend back as far as you can to try to counter balance the awful tip in your spine.  Doing that does NOT tip your pelvis into position it only causes you to hyper-arch your back.  It doesn’t fix the problem.

Warning: Destruction, degeneration and pain are graphically described here below and may not be suitable for sensitive readers! 

The excessively curved spine can cause many problems.  Compression of the posterior parts of the disks is one serious consequence.  A compressed disk will bulge.  A bulging disk can press on ligaments or nerves and cause pain (mild sciatica).  Next, the bulging disk will start to break down and degenerate (degenerative disk disease), possibly allowing a distinct backward bulge called a herniated disk.  These can cause severe sciatic pain. Herniated disks can also cause local back pain if they press on ligaments etc.

The spine also has pairs of joints between the vertebrae called facet joints.  In the healthy spine, these joints do not bear any weight, there is a slight gap between the upper and lower surface of the joint.  If the low back is excessively curved theses joint surfaces now grind against each other all day long.  They just weren’t built for that.  This grinding causes the joint surfaces to degenerate (degenerative joint disease).  This causes extreme low back pain due to osteoarthritis.  In a vain attempt to help themselves the joints will lay down bony ridges along the edges of the joint.  This does no good.  These sharp osteophytes can lacerate the passing nerves and cause nerve problems felt in the legs (pain, numbness, tingling.)

Muscles are dumb.  In response to all this pain the low back muscles will all tighten in an attempt to splint the back and reduce its movement.  This puts more strain on these already strained structures, causes more pain, and this can interfere with healing.  Now any movement is disabling, sleep is impossible, help is needed.  If you can, get help before this point!

And know what is the worst of all? Your mother was right! Your bad posture will be the ruin of you.

How can you get help? Well, moving the joints and disks of the low back  alone is not enough.  Recapturing the spring in the spine requires addressing the muscle imbalance as well.  Once the muscles are rebalanced the spine will start to tip back into its proper place and regain a more vital mobility.  No forcing of joints to move is required; there is no long term solution in just having the joints pulled apart (traction or decompression). Rather, have a massage therapist address all these issues in a whole body manner. By addressing the global musculature imbalance and restoring symmetry of posture both the joint and muscle pain are addressed directly and effectively.

Get the complete approach by a qualified registered massage therapist, and get that spring back in your step.


The following is from Massage Therapy Canada, and was further revised to be used in my textbook Clinical Assessment for Massage Therapy: a practical guide


Spinal Motions: Structure & Function

I want to talk about the living spine. Though speaking about the spine can be a humungous topic, my purpose here is to provide a general overall picture of the living spine, i.e. the spine in motion. I want to describe some of the ways in which the spine functions according to the nature of its structure, and also, show how the structure and function can become impaired or dysfunctional. What follows must be, by necessity, general in nature. Further, I will skip the pathological changes that may occur over time, or those due to disease processes.

The usefulness of looking at the spine in this way, even though it is removed from its environment in the body, is that it helps the therapist imagine, visualize those structures intrinsic to the spine and how they function. I call this type of exercise thinking anatomy, thinking through the implications of the structure and function of the musculoskeletal system. Structure (anatomy) permits and informs function, and function (physiology) shapes structure. In this way we can envision how the body seeks balance, successfully or unsuccessfully.

The spine acts as a spring or shock absorber for the trunk and head. Looking at the spine in profile, we see the familiar curves. These curves allow the spine to act as an S-spring. Pressure from above or below compresses the structure, but not like the loading like a solid column. Rather, the curves become exaggerated; absorbing the stress from the load, while the springiness inherent in it (via intervertebral discs, ligaments, muscles, living bone, etc.) pushes back. When the load is removed, the spine can lift itself back into it original shape , even without muscular action. This assumes that the load was not so great as to deform inert tissue or injure and impair muscle function.

Some of this absorption of forces comes from the intervertebral discs (IVDs). The intervertebral disc (IVD) is a polyaxial joint. It can accommodate any direction of motion, including shear forces, as well as compression and decompression. The ball shaped nucleus pulposus at the interior of the IVD as a gel is uncompressible, it cannot lose volume. When under pressure it pushes back. It acts as a self-righting mechanism for the spine, and this ability also allows the annular fibres around it (which can deform) to re-inflate. Further, the nucleus, as uncompressible,  acts as the axis of motion between vertebrae, as a swivel-type  joint. It remains gel like until middle age, when it then becomes fibrosed. As fibrosed, it loses its capacity to recoil to pressure, and so the cartilaginous layers can more easily lose their height.

The annular fibres, as cartilaginous, can lose water, when under pressure, and can therefore, be compressed, change shape. This compressibility provides the give within the spine, so that it can work as a shock absorber, that helps accommodate the compressive forces exerted on the disc. Therefore, the fibrous portion of the IVD, as compressible, can have its shape altered, when under stress. When the load or stress is removed these annular fibres reabsorb water, re-inflating. The principle motor driving this re-inflation is the nucleus pulposus.  However, if the layers are put continually or forcibly under stress their integrity can begin to break down.  Constant, or frequently recurring compression or stress, will prevent the annular fibres from taking back their water, leaving them dry and brittle. Then the gel-state nucleus itself will flatten and by necessity, it will begin to push its way outward through the cracks and breaks in the annular fibres and force the layers in front of it to bulge, herniate.

In the lumbar spine, the nucleus is not in the centre of the disc, but is positioned slightly posterior in order to better accommodate the compressive force when the spine is in neutral. In other words, because the lumbar anterior (lordotic) curve puts more mechanical stress on the posterior portion of the disc, the nucleus, being slightly posterior to center is better able to provide support. Therefore, as the lumbar curve exaggerates under load, the posterior-positioned nucleus provides protective support. As long as its integrity holds, the nucleus’ gel-state keeps it uncompressible, so it pushes back, recoil, and because of this, it can act as a self-righting mechanism. It helps the spine (bone, annular fibres, ligaments, muscles) return to normal shape once the load or mechanical stress is removed, and therefore helps restore its original form.

However, with flexion of the lumbar spine the compression of the anterior portion of the disc pushes the nucleus even more posteriorly. If the posterior cartilaginous layers are weakening (losing their integrity) then the nucleus will begin to shift even more posteriorly causing the weakened layers to bulge, or herniate. The posterior longitudinal ligament (which is quite narrow at the lumbar spine) often helps sustain the integrity of the most posterior fibres of the disc, and so the bulging nucleus often rolls out around this ligament and moves to the side, moving in a posterior lateral direction. This puts it on a collision course with  the neural foramen and the spinal nerve at that level. 

In the cervical spine, C2 to C7, the nucleus pulposus is also slightly posterior within the IVD, and therefore functions, or dysfunctions, much like the lumbar spine. The thoracic vertebrae have their nucleus pulposus more centred within the IVD. The lowest thoracic vertebrae, being slightly extended can have the nucleus slightly posterior; the flexed vertebra have it more centred.

We have talked mostly about flexing and extending portions of the spine. Side bending functions much in the same way, with the nucleus acting as an axis over which side-flexion occurs. These three motions, of course, do not only move as a teeter-totter does, there is, in addition, some shearing occurring as the vertebra above slides in the direction of flexing, extending, or sidebending. This shearing action can be more stressful to the annular fibres than compression is all on its own.

However, rotation is even more stressful on the IVD’s annular fibres. As the layers of annular fibres run (in general) in alternating diagonal directions, the stress/tension running through the fibres during rotation will be resisted by some, while others are actually made lax. With less fibres resisting the forces they are more likely to break down. Further, rotation also pulls the vertebral bodies closer together. This also reduces their ability to be shock-absorbers.

Facet (zygapophyseal) joints are meant to be slightly gapped when the spine is in neutral; (or, as some say, the facet joints idle – as in a motor of a car idling, not engaged or in use, but ready to be used). This occurs the closer the curves of the spine are to being ideal. The structures involved in facet joints (bone, articular cartilage, synovial fluid, joint capsules, ligaments, andmuscle) all contribute to the weight bearing ability through the area; yet the articular surfaces can remain gapped. The weight is distributed throughout the structure, where even the fluid in the joint can hold the joint surfaces apart, with the fluid playing a supporting role as forces move through the joint structures.  

However, as the curves exaggerate, the lordotic curves (cervical and lumbar) go into extension and the facet joint surfaces approximate and become weight bearing. These stresses going into the articular cartilage, similar to the cartilaginous annular fibres, lose fluid – it is literally squished out of them. This fluid mixes with the free synovial fluid within the capsule, making the capsule balloon, which still helps the joint, as a whole, resist the forces that are pressing through the boney facet process. However, the internal pressure of the fluid in this weight-bearing situation will stress the synovial and fibrous capsules and prevent nutrients from entering the synovial cavity. Therefore, the longer this hyper-lordosis persists, or the more extreme and forceful the extension: 1) The more quickly their articular surfaces will begin to break down and suffer other osteoarthritic changes; 2) the more likely an injury can occur to the capsules; and 3) for injury to occur to the intrinsic spinal ligaments and (fourth layer) musculature,  with some overstretched and some left shortened, and 4) the poorer the nutrition within the joint.

Now, when the spine moves from neutral, into extension, side-bending/flexing, and rotating, the facet surfaces not only compress but are also going to glide one over the other. This glide or skating also stretches the capsules, and will lengthen some supportive joint tissues, while making others lax. Flexing the spine gaps the joints but generally stretches most of the facet joint tissues. Therefore, any of these motions done, (or undo load), to the extreme, are going to strain and tear tissue. Further, combinations of these motions will exaggerate those forces straining the tissues.

I would now like to discuss what are commonly referred to as Fryette’s rules of spinal motion.  The first two were formulated by Harrison Fryette D.O. while a third was added by C.R. Nelson D.O. They have also been call Laws or Principles. I like to use the term rules, as they really should be taken as rules of thumb. They are informative about how the spine can move, but as is common with many living things, the spine does have a tendency to seeming not know these rules or chooses to ignore them.

Always remember too that every individual person’s spine is itself individual and unique. No two facet joints are absolutely identical from one person to another, nor are any individual’s two facet joints in their spine exactly identical. Each has at least some small, possibly trivial differences, while others can be shaped quite differently and so function differently, to various degrees. Even the adjoining facet joint surfaces can have different shapes (e.g., one with slightly convex surface while its partner may be basically flat),  be of differing sizes or even differ in orientation one to another.

We first need a couple of definitions and observations:

  • A motion segment of the spine is defined as two adjacent vertebrae and all the joints between them. There can be group or segmental motions in the spine: These are clarified in Fryette’s rules of spinal movements. Those rules were meant to specifically apply to both the thoracic and lumbar spine, but not the cervical.  

A couple of observations:

  1. Spinal movements are coupled. This means that any motion of the spine impacts on any other motion and, further, that some motions generally accompany each other. With respect to the last point, it has been proposed that sidebending and rotation are always coupled in the spine.
  2. The motions are named from the perspective of the vertebra above, with reference to the one below. Therefore, to say that a vertebra is sidebent and rotated is to say that relative to the vertebrae below, the vertebrae above is sidebent and rotated.

Fryette’s Rules Of Spinal Motions: These rules have been shown to be especially valid for the lumbar spine.

1. Fryette’s first rule of spinal movements: When moving from neutral, the spine sidebends first and then rotates in the opposite direction.

Comments -

Neutral, here, means the spine is neither flexed nor extended. Sidebending occurs in the frontal or coronal plane. Rotation happens in the transverse plane. When speaking of motions in neutral, sidebending occurs before rotation.

Kapanji says the following, to explain how this coupled movement in opposite directions occurs:

“This automatic rotation of the vertebrae ... [When sidebending/lateral flexion occurs] ... depends on two mechanisms – compression of intervertebral discs and the stretching of ligaments. The effect of disc compression is easily displayed on a simple mechanical model ... If the model is flexed to one side, contralateral rotation of the vertebrae is shown by the displacement of the various segments off the central line. Lateral flexion increases the internal pressure of the disc on the side of movement; as the disc is wedge-shaped its compressed substance tends to escape toward the zone of lower pressure, to rotation, i.e., contralaterally ... Conversely, lateral flexion stretches the contralateral ligaments, which tend to move toward the mid-line so as to minimize their lengths ... It is remarkable that these two processes are synergistic and in their own way contribute to rotation of the vertebrae.” (Kapanji, vol. 3)

2. Fryette’s second rule of spinal movements: When the spine is non-neutral – when in flexion or extension – rotation happens first, and then sidebending, both in the same direction.

Comments -

When the spine is working normally in flexion or extension, rotation precedes sidebending. Impairments, when they do occur, are likely if the order of vertebral motion is not synchronized. For example, if the spine is first in neutral and the client sidebends, and rotates and then flexes or extends, the chances for an impairment or dysfunction increase substantially. Knowing that the order of movements that produced the client’s injury helps the therapist understand how the client became lesioned. This information comes from a thorough case history taking.

3. Fryette’s third rule of spinal movements: Introducing motion to a vertebral joint in one plane automatically reduces its mobility in the other two planes.

Comments -

This rule is fairly self-evident. It is important, however, in understanding how injuries occur. Again, if the client’s spine is moved following the second rule as the vertebrae are flexed, some degree of motion is no longer available for sidebending and rotation. If, however, the person moves the spine into extremes in any of the three planes, that also greatly increases the chances of injury occurring. If the IVD and facet joints are driven too far, then injuries to the joint structures themselves and/or to the intrinsic muscles of the spine are likely to occur.

Types of Motion:

The first rule is often referred to as Type I motion. Type I dysfunctions usually occur as a group (as in a scoliosis, for example). Therefore, they are referred to as a group or neutral dysfunction, where a number of vertebrae sidebend one way and rotate in the opposite direction. A functional scoliosis means that  the scoliosis does not disappear when the client flexes or extends the spine. The vertebrae remain rotated and sidebent. However, in a bony (or pathological) scoliosis the vertebrae can be rotated and sidebent  to either opposite sides or to the same side; they will not be following Fryette’s rules.

The second rule is Type II motion. Type II dysfunctions occur most often when the spine is already flexed or extended, and then, sidebending and rotation are added. They usually occur in isolation, in a single segment strain, with lifting and twisting, as an example. In other words, they are segmental dysfunctions, generally not in several segments in a row, (as a group).  However, it is quite possible to have several segmental dysfunction, one on top of the other, but each should be treated as individual motion segments. Again, this will help us understand how to test for these types of lesions, and to understand the results of such testing.

Note that, when the spine seems in neutral, if the person has hyperlordosis or hyper-kyphosis, excessive curves, or flattened curves, then that portion of the spine is not in neutral and will function as type II motion, leading to type II impairments. So, for example, if a client with a lumbar lordosis due to an anterior pelvic tilt, now rotates or sidebends, the joints involved will follow the second rule (type II motion) rather than the first rule (type I motion).


Of special note: The spine is a continuum. Though we refer to portions of it as the lumbar, thoracic and cervical spine, many structures undergo graduated changes as we progress up the spine from the sacrum to the occiput. Of course, it is true that there are transition points, predominately where the ribs come into play: the cervicothoracic and thoracolumbar junctions. (We are ignoring the lumbosacral and occipital-atlantal junctions, as we are removing the spine from its context of the body as a whole.) The ribs have real impact, but we will get to that later.

The point is that the rules apply fairly consistently to the lumbar spine, and up into the lower thoracic spine. However, as the facet joints slowly, but progressively, change their orientation as they move up, or down, the spine, these rules are going to become less consistent as we move into the upper half of the thoracic spine. Till where they no longer apply to the cervical spine at all. Gradation in spinal structure (shape) results in a gradation of function, and a graduation of how predictive these rules of Fryette’s are.

The cervical spine, from C2 to C7 tends to move usually with sidebending and rotation occurring to the same side, either in neutral or when the cervical spine is flexed or extended. This is due to the orientation of the facet joint surfaces. However, these vertebrae can be made to move opposite to each other under special circumstances. Hence, Fryette’s rules do not apply to them. Further, the unique shapes of C1 and C2 means they move in their own unique way. There, structure informs their function, and vice versa.

Do all spinal lesions occur in these ways?

No. Lesions, by nature, may show patterns, but unusual traumas, severe blows or an unusual structuring or shape to the vertebrae can result in atypical patterns. The rules of spinal movement are meant to help explain common clinical findings. However, because everyone is unique, joint shapes differ from person to person. Any lesion may present as unique. You may, on a rare occasion, find a group dysfunction where the lumbar or lower thoracic vertebrae seem rotated and sidebent to the same side, for example. Alternatively, a segmental dysfunction could have the motion segment rotating and sidebending in opposite directions. After all, lesions are lesions because things have gone wrong! Lesions know no rules. The joints in the spine can be forced into moving (functioning) in ways that do not conform to their shape (structure). Thus, we need to know how to accurately palpate and test the joints of the spine and, more importantly, not make assumptions about how things should be and, thus, forgo the testing. We need to be open-minded enough in order to be prepared to find the unexpected.

Let us look at how the spine contributes to holding the body upright, how it bears the weight of the trunk, head and upper limbs.

Often the spine is still thought of, or described as a column (hence the classic name spinal column), that works mechanically like a column, supporting all this weight. However, this is no longer considered an appropriate model.

This is where one of the many important jobs the ribs perform comes into play. Rather than only transferring weight, and other stresses, onto the spine, the ribs can distribute a lot of the weight of the upper body outward, to the body wall.

This transfer of weight and forces outward is referred to in the concept of tensegrity. Tensegrity is a term coined by the architect, engineer and scientist R. Buckminster Fuller, who was the original designer of the geodesic dome. He said his inspiration for that design came from the structures within the living cell, its cytoskeleton. The term comes from contracting the words tensional integrity: This describes the forces at work in a structure that is formed by a network of compressive, rigid elements interconnected through tensile or elastic elements, which give the structure its overall integrity. Due to the elastic property of the interconnections, when one element of the tensegrity structure is shifted (moved and/or loaded), this shift is spread throughout the whole structure. All the other elements shift as well, adapting and compensating by morphing into a new configuration. By yielding, in this way, to these shifts such a structure is more accepting of the forces or loads applied, without breaking.

In this way, the ribs, and all the other tissues and structures of the spine working together, disperse stresses and strains that would snap if they were a rigid structure. Therefore, the ribs also help the body absorb the forces of walking, running, weight bearing, reaching, pulling, etc. This is in addition to their duties of being the bellows for breathing and fluid movement (as part of circulatory system, especially for venous and lymph flow through the trunk). The qualities of tensegrity also help the ribs, and their related tissues, be even more effective in protecting the organs within the trunk.

By looking at the spine in this way, by seeing its function as guided by its structure, and how its function can shape structure, the therapist is better equipped to understand how the spine works and how it gets into trouble. We can only see this way if we are looking at the spine as a living, changing, adapting system.