Masticatory Muscles Are The Bridge
The TM joints and their governing masticatory muscles are surrounded by two interrelated issues: the mobility and congruent fit of the cranial bones above, and the intercuspal position below (how the teeth fit together – often referred to as occlusion).
Because the mandible is suspended by soft tissue,2 it is proposed that the masticatory muscles act as a bridge connecting the two issues. Their success or failure in adapting to cranial and/or occlusal asymmetry is a valid and often important component in the cranio-mandibular complex, and yet many practitioners see the masticatory musculature as irrelevant.
A recent seminar, facilitated by an Ontario orthodontist, courageously explored the connection between occlusion and cranial “lesions” such as torsion, shear, hyperextension, etc. A table of MTs, craniosascral therapists and an osteopath attended and were called upon to give input now and again. While this meeting of the minds was promising, there was not a single moment where the dentists and orthodontists acknowledged the masticatory musculature!
The prevalence of clenching in our society with the resulting asymmetrical hypertonicity and joint compression is enough for massage therapists to intervene.
Developing mastery in the region contributes to the overall toolbox we offer our clients and acknowledges that the TMJ dysfunction may be local, or may be part of a larger whole-body pattern.
Mastery is a lifelong process in which focus is given to a specific subject in order to cultivate expertise. In the case of intra-oral work, expertise is often a function of the practitioner’s ability to access the Pterygoid group.
|Initial Landmark; Inside edge of the Pterygomandibular Raphe.
Part One explored the Mandibular Sling as the “reigns” of mandibular movement. Each side is comprised of the Masseter muscle and the Medial Pterygoid muscle with fascial continuity. The sling works in conjunction with Temporalis muscles to supply mandibular closure and loaded masticating forces. A staple in the treatment of TMJ dysfunction is resolving the asymmetry found in the length and strength of the Mandibular Sling. It is however, tempting to fall into the ease of Masseter muscle access and avoid the perceived difficulty of the Medial Pterygoid access. In order to achieve an effective sling re-patterning both participating muscles must be worked.
The complexity of the TMJ topic is revealed further when we acknowledge that the mandibular fossae – in which the condyles reside – are part of the Temporal bones. We know from Osteopathic/Craniosacral principles that the orientation of the mandibular fossae is set by the flexion and extension of the individual Temporal bones as part of the Craniosacral System.3 To simplify; if the sockets are not symmetrical then the condylar function cannot be symmetrical (similar to the Scapular/Humeral relationship).
The grinding of our food is achieved in part by the partnership of a Masseter muscle working with its contra-lateral Medial Pterygoid mate. This is coupled with the contra-lateral adaptive patterns we see in many TMJ clients; symptoms of pain and overworked tissue on one side (hypermobility), with the mechanical “causes” on the other side (hypomobility), most often recognizable by the side with delayed condylar movement.
Pterygoid Muscle Access: The Gem of Intra-oral Work
Accessing the Medial Pterygoid muscle (the “vertical” one) is possible by first placing a Nitrile gloved index finger between the rear molars finding and resting on the inside edge of the Pterygomandibular Raphe - the anterior bony ridge of the ramus of the mandible.
Once there, delay a moment and instruct your client to rest their teeth on your finger – an exchange of vulnerabilities for certain. Waiting a few moments gives your client an opportunity to become accustomed to being touched there, and establishes that neither the openers nor the closures are employed. It also provides the important step of giving the gag reflex a chance to retreat!
Remind your client to inhale as he or she is likely breathing shallowly at the moment of access. Begin to glide medially and posterior until you leave the hard ridge of the Raphe and begin to move toward the medial aspect of the ramus of the mandible. Immediately medial to the Pterygo-mandibular Raphe is a curtain of tissue that varies in thickness from person to person called the Palatoglossal arch. For some clients it is necessary to navigate medially around this curtain as you travel backward. As you do you will arrive on soft tissue; this is Pterygoid country.
This is also where the client’s Palatine tonsils were, or are, located – lying directly over the posterior aspect of the Medial Pterygoid muscle. Occasionally, adults that still have their tonsils present with recent infection episodes which render the Palatine tonsil enlarged and spongy with residual inflammation. This is fortunately rare as it presents a local contra-indication to Medial Pterygoid access.
Full access is attained when half to three-quarters of your distal finger pad is on soft tissue just behind this Palatoglossal arch (see facing page). Once there, ask how the gag issue is doing. As established in Part One, remember that treatment effectiveness is achieved by repetition, not duration. It is very helpful to offer a verbal countdown of “5, 4, 3, 2, and I’m out,” so that the client knows when the access increment is about to finish. Many clients have remarked that this practice makes all the difference in tolerating Medial Pterygoid contact.
|Accessing the Medial Pterygoid muscle – from the Pterygomandibular Raphe moving to the red line is effective access.
By flexing the “dip” joint of the intra-oral finger slightly you will initiate what is “a conversation with the tissues.”4 This is the point of transition from accessing the Medial Pterygoid muscle, to treating it. Only five to 15 seconds of pressure into the muscle belly is needed to be an effective increment of treatment.
This is an intent-phenomenon similar to doing direct work on the Psoas muscle through the abdominal wall. However, it is not a long enough duration to be Ischemic Compression, and, as it is stationary contact on slippery tissue, it is not possible to engage fascial membranes. By accessing the Medial Pterygoid muscle and pressing into it slightly, different levels of resistance is often found between left and right sides. As each increment of contact is pursued, the resistance gives way and deeper palpation becomes available without having to use more force, or engaging more tenderness.
This defines a release of the hypertonicity, and the accumulation of each increment creates effectiveness.The client is focused, breathing and resting her teeth on the index finger. The intent is to provide this release often enough where continuity of treatment creates a re-patterning of the hypertonicity back to a more symmetrical length and strength of the Medial Pterygoid muscles.
Power, function collaborate
While the Masseter muscle is known as the “power chewer,” the Medial Pterygoid muscle is known as the “function” mover of the joint. Power and function collaborate, but as the Medial Pterygoid steers the system more than its sling-mate, its symmetry of length and strength has a greater role in whether the whole system is operating harmoniously.
Also, remember the Medial Pterygoid muscles originate on the Sphenoid bone and therefore contribute to whether there is symmetrical Sphenoid movement along the median sagittal plane, or if it is being pulled toward the shortened hypertonic side.
Undeniably, no one is symmetrical all the time. Most of us have some cranial lesions and malocclusion. The degree to which it occurs determines if homeostasis is present, or if a threshold is reached at which a pathologic level of disturbance is declared. The masticatory musculature responds to the lesions and malocclusion, and the resulting threshold of asymmetrical hypertonicity and joint compression may well reach problematic levels.
A Syndrome: a set of signs working together
When observable signs show up repeatedly, a syndrome can be declared as a tool to succinctly communicate about them.
As massage therapists, our reference manuals acknowledge many different syndromes: Piriformis syndrome, Psoas syndrome, Thoracic Outlet Syndromes, Carpal Tunnel Syndrome and certainly TMJ syndrome to name a few. Syndrome comes from the Greek syndromos meaning a running together, a meeting. Stedman’s Concise Medical Dictionary defines it as “the aggregate of signs and symptoms with any morbid process.”
Given the important steering role of the Medial Pterygoid muscles the system displays recognizable signs once a pathological threshold of asymmetrical hypertonicity is reached. The following definition then applies:
Medial Pterygoid Syndrome:
Asymmetrical hypertonicity of the Medial Pterygoid muscles resulting in loss of symmetrical movement of the mandibular condyles leading to compensatory movements, unilateral or bilateral disc dysfunction, and possibly joint degeneration.
The scenario is characterized by:
- Delayed condylar movement (A primary side and contra-lateral compensations
- Diminished joint space and joint fluid
- Pain, point tenderness and/or referral pain
- Reduced ability to open mouth
- Often Articular Disc displacement
- Without restorative treatment – Articular Disc breakdown; perforation, obliteration.
Once confidence of the Medial Pterygoid muscle access has been established it becomes possible to consider access of the Lateral Pterygoid muscles. This allows the practitioner the possibility of addressing its influence on the position of the Articular Disc.
Lateral Pterygoid Muscles Conjoined Twins with Opposing Function
Some clinical anatomy texts still depict the Lateral Pterygoid as one muscle with two “heads,”5 or as having the same function of opening.6 In recent years, the use of MRI in combination with Electro- myography has demystified the Inferior Lateral Pterygoid and the Superior Lateral Pterygoid as two
distinct and different muscles.7
Lying one on top of the other, both muscles originate on the Sphenoid bone and travel “horizontally” back toward the neck of the condyle, deep to its Medial Pterygoid cousin.
When the Inferior Lateral Pterygoid muscle contributes to mandibular opening it draws the condyle forward and down like a rower pulling on her oar. However, the Superior Lateral Pterygoid muscle fires as the jaw exerts a closing “power stroke,” that is, during loaded chewing on food (or clenching). With up to 40 per cent of its fibres attached to the Articular Disc8 it matches the rear pulling forces of the Retrodiscal Lamina, the only tissue imparting retraction forces on the Articular Disc.
If the following scenario is present: Then the disc remains correctly placed on the head of the condyle. The intent of the practitioner in combination with his or her knowledge of correct anatomy ensures that the Lateral Pterygoid muscles are palpable through the superior portion of the Medial Pterygoid muscle,
making treatment possible.
Muscle Action Insertion
Inferior Lateral Opener Neck of condyle
Pterygoid (condyle forward & down)
Superior Lateral During Closing 30% to 40%
Pterygoid (anterior pull on to Articular Disc,
Articular Disc remaining 70% to
matching neck of condyle
Access of the Lateral Pterygoid group is further addressed in Part Three where decompression mobilization technique and the continuum of disc displacement are explored in the context of whether it is possible to manage such presentations.
Decompression mobilization: Encourages restoration of joint space • small amplitude • low force • repetitive • palpate joint during to confirm amount of force needed.
1. Jaw Survey; “Whether at night or day, during stress or pain, or part of concentration, etc., do you clench your teeth?” March 2007.
2. Okeson, Jeffrey P: Management of Temporomandibular Disorders and Occlusion, 5th Edition: Lexington, Kentucky, 2003. P. 6
3. Upledger, John: TMJ; Primary Problem or Tip of The Iceberg, Massage Today, August 2002, Vol. 2, Issue 8.
4. Kluszinski, Vlodek RMT, DO. OMTA Hands Together Conference 2002; Assessment and Treatment of Psoas Syndrome. Instructor quote
5. Snell, Richard S. Clinical Anatomy 7th Edition, Table 11-3 on p.772, and fig. 11-40 on p. 782
6. Hoppenfeld, Stanley; Physical Examination of the Spine and Extremities, p. 129
7. Okeson, Jeffrey P: Management of Temporomandibular Disorders and Occlusion, 5th Edition: Lexington, Kentucky, 2003. p. 19
8. Ibid, p. 20
| John W. Corry, RMT
• John Corry graduated in 1989 from Sutherland-Chan School and Teaching Clinic in Toronto. He has been a Treatments & Techniques instructor, delivering the Ontario 2200-hour program, has presented at workshops and international fitness conferences, and has been a career-long member of the Ontario Massage Therapists Association, twice being a local chapter president. He pursues a level of excellence in innovative applications, and started focusing on TMJ cases in 1992. He facilitates a three-day instructional workshop called TMJ Mastery and works at Wholistic Body & Baby in the core of London, Ontario.