What is Temporomandibular Joint Dysfunction Syndrome?

Temporomandibular Joint Dysfunction Syndrome (TMJD from herein), is a broad term that refers to the dysfunction of the articulation between the mandible and the cranium – aka the TMJ or temporomandibular joint. TMJD is not exclusively a disorder of the bony structures, but may also be a result of hypertonic muscles which affect the joint and therefore cause symptoms.

Temporo refers to the temporal bone of the cranium (skull), and mandibular refers to the mandible or jaw.

Symptoms of Temporomandibular Joint Dysfunction

In early stages there is often a clicking or popping noise when a client opens or shuts his or her mouth. As the condition progresses, there may be pain at the site, which is just in front of external auditory meatus (ear canal), the temple or the teeth. The noise or the discomfort usually presents unilaterally, however it can present bilaterally.

Poor coordination of the muscles leads to deviations in movement as the jaw opens or closes. For example, if looking in the mirror, a client may notice that when she opens her mouth, her jaw is pulled to one side.

In severe cases, the jaw may become dislocated and stuck open, and the surrounding muscles may spasm.

Who is at risk for TMJD ?

Temporomandibular Joint Dysfunction appears to occur more often in women, and in the age group of 20 – 40 years. It is common in people who have suffered trauma to the jaw and face, who have suffered whiplash (a WAD injury) or who may have had a lot of dental work or surgery. Other conditions such as excess muscle tension can lead to malocclusion, or arthritis may affect the joint.

TMJD also appears to worsen in those who have extreme postural deviations, such as scoliosis or anterior head carriage.

Anatomy of the Temporomandibular Joint

The TMJ is a hinged synovial joint, and is an articulation of the head of the mandible with the mandibular fossa and articular tubercle of the temporal bone.

Within the joint is an articular disc whose purpose is to cushion the bony surfaces during movement. This articular disc divides the joint capsule into a superior and an inferior compartment: superiorly between the disc and the mandibular fossa, and inferiorly between the disc and the head of the mandible.

The TMJ is located anterior to the external auditory meatus or ear canal, hence the ear pain in some cases of TMJD.

The mandible is suspended from the cranium primarily by the fibrous capsule of the TMJ and lateral ligament of the joint, in addition to the sphenomandibular and stylomandibular ligaments medially and inferiorly. The latter 2 ligaments serve to stabilize the joint during movement by opposing the pull of the capsule and lateral ligament.

Movement of the Temporomandibular Joint

The temporomandibular joint is moved by what are known as “the muscles of mastication”. There are 4 of these muscles, the temporalis, masseter, lateral and medial pterygoids.

The primary mover of the TMJ during opening (or depression) of the jaw is actually gravity – this is assisted by the lateral pterygoid muscle as well as the supra- and infrahyoid muscles. The lateral pterygoid is the only muscle of mastication that depresses the jaw.

The lateral pterygoid, and to a lesser degree, the masseter and medial pterygoids act to protrude the chin.

To elevate the mandible (close the mouth) the temporalis, masseter and medial pterygoid muscles contract.

To retract the chin, the temporalis and masseter contract.

Action of the disc during an opening/depressing movement of the TMJ

There are 2 movements which occur in the TMJ – first, the head of the mandible rotates anteriorly, secondly, the head of the mandible glides anteriorly as it continues to rotate anteriorly.

To open the mouth, the lateral pterygoids contract, and with the assistance of gravity, pulls the articular disc taut in the joint capsule.

As the head of the mandible moves anteriorly along the mandibular fossa of the temporal bone, the articular disc is pulled anteriorly as well, always staying between the two articulating bones. The correct end-range of this movement is at the articular tubercle of the temporal bone.

Dislocation of the TMJ occurs when the head of the mandible slips anteriorly to the articular tubercle. This may occur due to spasm of the lateral pterygoid muscle as the client opens their mouth.

Dislocation may also occur due to a sideways blow to the jaw when the mouth is open. It is not uncommon for the arm of the mandible to break instead of the actual TMJ dislocating.

Functional dislocation of the articular disc occurs when the disc is unable to move normally with movement of the head of the mandible. This dislocation may occur anteriorly or posteriorly to the head of the mandible.

An anterior dislocation can be differentiated by difficulty and pain with opening of the mouth, with the available movement being very limited. This is a result of the disc becoming compressed between the mandibular head and the articular tubercle and lateral pterygoid.

Difficulty and pain with elevation (closing) of the mandible, and a possible inability to close the mouth completely, is an indication of a posterior dislocation, where the articular disc is jammed against the posterior aspect of the joint cavity.

Failure of the disc to move properly within the joint capsule is believed to be the cause of the clicking sound which is often heard. The incorrect movement may be due to hypertonicity of the muscles of mastication, articular surface degeneration etc.

© Copyright 2010 Jodi Forsythe
www.whymassagetherapy.com
All Rights Reserved.

What are the Causes of Low Back Pain

Low back pain is one of the most common conditions treated by massage therapists. I have been asked by countless clients “what are the causes of low back pain?”, and I am afraid to say that there is no simple answer. The causes of low back pain are many, and it is important for clients to understand this, as appropriate treatment approaches differ as much as the causes themselves.

So common is low back pain that I decided to do a little research and try to get some statistics on it.

Here is what I found:

Back pain statistics from the Workers Compensation Board of British Columbia

From 2000 to 2004 WorkSafeBC (Workers’ Compensation Board) received over 107,000 claims for back strains

back strains account for just over 25% of all WorkSafeBC (Workers’ Compensation Board) claims.

Roughly 30% to 40% of all workplace absences in Canada are due to back pain

injuries may be caused by a single instance of overexertion or develop as a result of repeated motion over time.

Over two-thirds of back injuries are a result of overexertion

60% to 90% of the population will experience low back pain in their lifetime

More than 90% of low back pain cases have no specific cause (such as infection, osteoporosis, arthritis, etc.). In these cases the pain will usually subside without treatment in four to six weeks.

In the health care industry, injuries due to patient handling (lifting, transferring, or repositioning) account for about 35% of all accepted time loss claims and for about 40% of claim costs.

So, that’s all fine and well, but while “back strain” appears to be the most common cause of low back pain, and quite a generic term, there are other causes of low back pain. It is very important to identify the cause and contributing factors to low back pain for successful treatment, otherwise clients may just end up wasting time and money.

Falling into each of these 4 broad categories, which I am going to name as causes for low back pain, are several different conditions which I have seen in my practice.

Low back pain cause – Muscle fatigue or strain

Also referred to as a “pulled muscle”, this happens when muscles are overused or is weak. Muscles can also be torn from an injury, and of course, the more serious the damage, the longer it will take to heal …

This is also the primary participant in “soft tissue injuries” – the effects of which insurance companies have lead people to believe are minimal. The reality is that soft tissue injury, and the chronic inflammation which may accompany the more severe injuries, often take longer to heal than the ballpark figure in the insurance tables. However, I digress …

Pain can also be caused by an imbalance of muscle development, or a lack of “extensibility” or “stretch” of the muscles. This is very easy to see, for example, in athletes who may overuse and overdevelop one muscle group. This muscle imbalance is stressful for the body and may cause pain and spasm in the opposing muscle group as the body tries to maintain homeostasis. This lack of balance can lead to “mechanical dysfunction” of the joints of the back (see below). Muscle imbalance, can, however, be treated at home if you know what to do.

Low back pain cause – Joint and bone dysfunction

This type of back pain is often referred to as “mechanical back pain” or “mechanical joint dysfunction” when referring specifically to the joints. What this means is that a joint is not able to move as it is meant to, either from injury to the bone or joint, or hypertonicity of the surrounding muscles (hyper meaning ‘too much’, tone means the amount of tension in the muscle). Unfortunately, this can lead to several other issues and can be a self-perpetuating cycle if left untreated, often causing seemingly unrelated problems.

Of course, bones and joints can also be affected by fractures, breaks, arthritis and a multitude of other conditions which is well beyond the scope of massage therapy to diagnose and in some cases, treat. Massage therapy can, however, be used to alleviate symptoms and assist in recovery.

Low back pain cause – neurological

Low back pain from a neurological source can be a result of a variety of triggers, all of which are related to either the intervertebral disc, spinal cord, or the “nerve roots” as they exit the spinal cord. This type of pain can be excruciating and very debilitating, as anyone with a “slipped disc” will tell you. (this is a bit of a misnomer, and will be addressed in upcoming articles). This type of low back pain usually presents as symptoms in the area which the affected nerve root supplies, so the location of the symptoms is really dependent on the nerve root “level” where the injury or restriction happened. (and often the level of the injury is determined by the presentation of symptoms.) Pain which occurs in one area but originates from dysfunction in another area is called “referred” or “referral” pain.

Low Back Pain – Neurological from Bulging, or Herniated, Disc

Low back pain cause – visceral referral

In some cases pain can be a result of a dysfunction or infection of an internal organ. This happens because the “nociceptors” (pain receptors) of an organ are irritated and the pain is either felt in the skin or tissue which is superficial to (or just above) the organ, or in a classic “referral pattern”. Pain caused by visceral dysfunction can be quite severe.  A classic example is low back pain in the lumbar area which may wrap around a persons front, or extend down the sides of the thighs and into the groin.  This is a referral pattern of the kidneys, and should never be ignored.

Remember, most low back pain is a result of muscle weakness or imbalance. However, if you are not aware of any activity or cause of the pain, the pain is severe, or if the pain has been present for any length of time, I would urge you to see a physician immediately to rule out anything more serious than a muscular cause for the pain. You may also want to check out more information I have found on WebMD.

© Copyright 2009
www.whymassagetherapy.com
All Rights Reserved.

Massage Therapy and Anatomy – Arthrology Definition

Arthrology is the study of joints.

Joints occur where the surfaces of 2 or more bones meet. An articulation is another term which refers to a “joint”

Why is arthrology important to massage therapy?

Massage therapists work with the musculoskeletal system. Clients may present with symptoms which may be confusing – it is necessary for a therapist to assess a client’s presentation and form a clinical impression – meaning, his or her opinion on the cause of the symptoms. (remember, massage therapists are not permitted to provide a diagnosis).

Muscles cross joints to produce movement, and any joint dysfunction may lead to muscular imbalance and pain. Muscle tone which doesn’t support a joint (hypotonic – meaning not enough tone), or restricts movement too much (hypertonic – meaning excessive tone), may cause pain in the joint itself.

For a therapist to successfully treat the underlying cause of any symptom, he or she must understand the relationship between muscles and the joints which they cross, as well as the anatomy of the joint itself.