If you suspect you may have a temporomandibular joint dysfunction (TMD) the following information may be helpful for you. In this blog article we’ll try to explain what we evaluate when assessing the TMJ (temporomandibular joint) for TMD (a temporomandibular dysfunction).
Your ability to open your mouth (technically termed mandibular range of motion)
The normal range a person’s mouth opens is about 40 to 50 mm (around 3 finger-widths). If you are only able to open your mouth to fit just about two fingers or less, then you have a limited range of motion for jaw opening. Observe yourself in a mirror as you are opening, can you open in midline? If you notice a deviation or deflection to one side with opening, it indicates a dysfunction caused by either a muscular imbalance or TMJ disc pathology. Other movements to look at are the ability to protrude your jaw (jut your chin out) the normal range of motion for this movement is 3-6 mm and again you should be able to do this in midline, without a shift to the right or left otherwise you are looking at a muscular imbalance or disc pathology. Also observe your ability to move your jaw from side to side this should be about 10 to 14 millimeters in each direction symmetrically. Do you hear sounds when you open, close, protrude or move laterally? A clicking sound when opening or closing your jaw are indications of a disc problem a crunchy sound is more likely arthritic changes in your joint (“arthritis”).
Evidence of teeth grinding (one common parafunctional habit associated with TMD) or clenching
Examine your teeth and check for indication of wear that may be caused by teeth grinding. You will most likely know if you have a habit of grinding your teeth but some people do this at night only and are not aware of it however the wear on your teeth will not lie. If you clench your teeth verses grind them you might see vertical cracks in your teeth. The tongue may have “scalloping” features meaning it has teeth indentations on its borders. This is a result of constantly sucking hard on the tongue which has the same effect as clenching while not actually damaging the teeth, this habit can place unnecessary pressure on the jaw muscles. One result of too much chewing and sucking on the cheeks’ inside is the formation of a white line or “linea alba” on the inner side of the cheek.
Palpation
Masticatory muscles (chewing muscles) such as the suprahyoids (located beneath the chin), medial pterygoid (found beneath the jaw angle), masseters (cheek), and temporalis (from your temple up into your hair line) should be evaluated for hypertonicity (medical term for tension) or tenderness. Comprehensive evaluation of the temporalis and the masseters require intraoral palpation. For testing the stretching capability of the masseter muscle, the practitioner places their thumb inside your cheek with the rest of their fingers remaining outside; and gently squeezes the cheek and presses their thumb out into the cheek at the same time. This procedure should to be pliable and painless. To feel the temporalis tendon for any tenderness and protrusion close to where it’s attached, the practitioner slides the finger through the superior gums, in between the coronoid process (an extension on the mandible) and the maxilla.
Accessory Joint Motion (important secondary movements within the joint )
As with every healthy synovial joint, the TMJ joint needs to have a pain-free and springy feel. Synovial joints are mobile joints that are lubricated by a substance called synovial fluid making the connected bones in the joint move effortlessly. Both Temporomandibular joints move simultaneously making it imperative for both joints to possess the same mobility. If one joint is less mobile than the other, this may cause excessive torque on one side that may result in ligament strain on that side. Both TMJs should glide anteriorly and gap with distraction and, moreover, should possess a small amount of lateral accessory, medial and posterior motions. The gapping of the TMJ can be evaluated through light palpation of one TMJ using the fingertips, while applying downward pressure using the other hand on the mandible through the thumb on the lower molars. When distraction has been evaluated, you can apply similar hand placement for assessing anterior glide. This is done by pulling forward mildly on the mandible. Similar hand placement can also be applied for lateral, medial and posterior glide evaluation.
The information we are sharing in this blog post is not meant as medical advice or for self diagnosis in any way. It is simply for informational purposes. TMJ disorders and TMD are conditions that require the attention of a trained medical professional.
If you suspect you suffer from a TMJ or TMD dysfunction, contact your healthcare practitioner or give us a call.