SCREENING FOR TMJ DISORDERS

A Simple, Non-Invasive Method

A simple, non-invasive method to screen for Temporomandibular (TM) joint disorders is the LAT-Exam and the EAM-Exam. This combined exam is quite accurate with a dependable and repeatable result.   The term LAT-Exam is derived from the principal anatomical landmarks that are utilized in the exam.  LAT refers to the lateral ligament position of the examiner's hands on the subject's face.  The position of the examiner's index and middle finger is directly over the lateral pole of the subject's condylar head of both TM joints.  The location of the condyles is one finger-width forward of the tragus of the ear or approximately 12 mm forward of the tragus.  (See Figure 1) Palpation at this point will allow the examiner to: Palpate or feel any major joint vibrations (you may not feel some internal derangement) Stabilize the lateral Temporomandibular ligament during the open-close cycle of the jaw movement Palpate joint pain or dysfunction upon opening and closing.  Figure 1     Any palpable jaw joint sounds or pain or any deviation or deflection in jaw movement from a straight vertical open-close should be considered suspect of a possible internal derangement or TM Disc displacement. Figure 2 To palpate the TM  joint laterally, the examiner places their first and second finger just anterior to the tragus of the patient's ear.  As the patient opens wide, you will feel your finger tip drop into a depression overlying the joint and behind the advancing condyle and directly under the zygomatic arch.  (See Figure 2) Figure 3  Now ask the patient to open and close several times. This allows palpation of the condylar translation.  Be sure to do both sides simultaneously to most accurately assess both joints (See Figure 3) and observe any deviation or deflection or lateral (right or left) jaw movements as an indication of internal derangement.  Figure 4   The EAM-Exam (External Auditory Meatus) allows the examiners to feel the posterolateral condylar surface when the jaw is at near closure.  Upon patient opening the posterior border of the medial Temporomandibular ligament can be stabilized and palpated. (See Figure 4). Any pain, deviation or deflection of vertical jaw movement, either right or left, is suggestive of internal derangement. Any positive pain response or jaw deviation during screening should be objectively measured utilizing Sonographic Imaging.