A client may report difficulty moving the jaw forward, jaw stiffness, clicking, discomfort chewing, symptoms with biting, or a feeling that the jaw does not move evenly.
The TMJ Translation Test gives a simple way to quantify forward jaw movement. It does not explain the cause of reduced translation on its own, but it provides useful baseline information when interpreted alongside pain, symptoms, jaw opening, lateral deviation, TMJ sounds, cervical range of motion, headache history and chewing tolerance.
Test name: TMJ Translation Test
Alternative name: Mandibular Protrusion Test
Purpose: Measure forward jaw movement
Movement: Moving the lower jaw forward
Joint/body region: Temporomandibular joint and jaw
Plane: Primarily sagittal plane
ROM type: Active protrusion, assisted protrusion or symptom-response assessment
Score: Mandibular protrusion in millimetres
Equipment: Millimetre ruler, disposable measurement card, calipers or Measurz recording workflow
Best used with: TMJ depression, lateral jaw deviation, jaw closing, cervical ROM, headache assessment, chewing function and symptom tracking
Key limitation: Protrusion values vary by dental alignment, overjet, symptoms, measurement method, client effort and TMJ movement strategy
The TMJ Translation Test measures forward translation of the mandible.
In most clinical and field settings, the client moves the lower jaw forward as far as comfortably possible. The forward movement is then recorded in millimetres.
The result may be recorded as:
active protrusion distance
assisted protrusion distance
symptom response
deviation during protrusion
TMJ sounds
pain location
movement quality
client tolerance
The test is used to establish a baseline, compare change over time and monitor jaw movement.
It may help inform:
mandibular protrusion capacity
TMJ movement monitoring
symptom response during jaw translation
chewing and biting tolerance
oral appliance or dental context where relevant
headache or neck-related assessment context
progress tracking after changes in symptoms or loading
decisions about whether related tests would add context
The test measures forward movement of the mandible in millimetres.
It may be influenced by:
TMJ translation
mandibular control
dental overjet or overbite
pain or symptoms
muscle guarding
jaw deviation
joint sounds
cervical posture
headache symptoms
client effort or apprehension
measurement method
professional technique
Reduced TMJ translation provides movement information, but it does not explain the cause on its own.
Active TMJ translation measures how far the client can move the jaw forward using their own control.
Assisted or passive protrusion measures how far the jaw can move when gentle assistance is provided.
Comparing active and assisted protrusion can help separate available movement from pain inhibition, guarding, confidence or motor control.
Passive or assisted movement should be gentle and should not force symptoms.
This test may be useful for clients with:
jaw stiffness
reduced forward jaw movement
symptoms with chewing or biting
jaw clicking or catching
symptoms during jaw movement
headache or neck symptoms with jaw involvement
difficulty tolerating oral tasks
side-to-side jaw movement differences
need to monitor jaw movement over time
It is also useful when comparing jaw movement across sessions.
Disposable millimetre ruler or measurement card
Calipers if available and appropriate
Gloves if required by setting
Mirror if observing deviation
Pain or symptom scale
Measurz for recording ROM, pain, symptoms and progress
Optional notes for TMJ sounds, deviation and cervical symptoms
Position the client sitting upright in a relaxed posture.
Use the same position for every retest.
The client keeps the head steady, shoulders relaxed and eyes facing forward.
Stand or sit in front of the client so the jaw, lips and teeth can be observed.
Ask the client to begin with the teeth lightly together or jaw relaxed, depending on the protocol.
Avoid holding the jaw unless performing an assisted version. Keep the head and neck position consistent.
For active protrusion, ask the client to move the lower jaw forward as far as comfortably possible.
For assisted protrusion, gently assist only if appropriate and within scope.
A common method is to measure how far the lower incisors move forward relative to the upper incisors.
If overjet is present, record the measurement method clearly so retesting remains consistent.
Choose one consistent method:
measure total forward position from upper to lower incisor relationship
measure protrusive movement after accounting for overjet
record visible protrusion in millimetres using the same landmarks
record whether protrusion produces deviation, symptoms or joint sounds
Ask about pain, stiffness, clicking, catching, locking, headache symptoms, ear symptoms, tooth discomfort and whether the movement feels familiar.
Stop if pain increases sharply, the jaw locks, symptoms spread, dizziness occurs, the client becomes apprehensive, or movement is not tolerated.
Record active or assisted method, protrusion distance in millimetres, pain score, symptom location, joint sounds, deviation, dental landmark used and stopping reason.
One to three trials may be used. Record the best, average or selected trial consistently.
Use the same position, landmarks, measurement tool, movement instruction and endpoint definition each time.
The score is recorded in millimetres.
A higher value generally indicates greater mandibular protrusion under the tested setup. A lower value indicates less forward jaw movement compared with previous baseline, broad reference values or the client’s functional needs.
Interpretation is stronger when combined with:
pain score
symptom location
active versus assisted protrusion
TMJ depression
lateral jaw deviation
jaw deviation during protrusion
TMJ sounds
chewing tolerance
cervical ROM
headache symptoms
related TMJ movement tests
The result does not explain the cause of reduced movement by itself. It helps guide monitoring, education and further assessment decisions.
Evidence level: Level 3 — broad reference values are available, but exact values vary by method, dental alignment, symptoms and client characteristics.
Common clinical references often describe mandibular protrusion around 5–12 mm, with many sources using approximately 7 mm or more as a practical lower reference for protrusive movement.
Practical benchmarks:
Typical field range: approximately 7–12 mm
Functional lower reference: around 5–7 mm may be used in some contexts
Reduced protrusion profile: below approximately 5–7 mm may be worth monitoring, especially with symptoms
Clinically useful finding: reduced protrusion, painful protrusion, deviation, clicking, catching or change from baseline
These values are broad guides, not diagnostic cut-offs.
The most useful comparisons are often:
baseline to retest
active versus assisted protrusion
pain at end range
deviation pattern
chewing or biting function
related TMJ depression and lateral deviation findings
related cervical and headache findings
TMJ range-of-motion measurements are commonly used in jaw assessment and can be useful when measurement procedures are consistent.
Reliability improves when:
the same measurement landmarks are used
overjet or incisor relationship is recorded
the same ruler or device is used
active and assisted measurements are labelled separately
symptoms are recorded
joint sounds are documented
the same client position is used
the same endpoint definition is used
Validity depends on the purpose. TMJ translation measurement reflects forward mandibular movement under the chosen protocol. It does not identify the cause of reduced movement, diagnose a TMJ disorder, or determine whether symptoms are joint, muscle, dental or cervical in origin.
Small changes should be interpreted cautiously unless they are repeated and align with symptoms, function or related testing.
Common errors include:
not recording active versus assisted protrusion
not accounting for overjet or dental alignment
measuring from inconsistent landmarks
forcing end range
not recording pain or symptoms
not recording deviation or joint sounds
comparing different measurement methods
using the result as a diagnosis
failing to record whether protrusion was comfortable or maximum
Limitations include:
dental landmarks may vary or be missing
overjet and tooth position influence readings
pain and guarding may reduce protrusion
jaw deviation can affect measurement
client effort influences active protrusion
symptoms may fluctuate day to day
the test does not identify tissue source
the test does not determine treatment need on its own
Use TMJ translation measurement to:
establish baseline mandibular protrusion
monitor jaw movement over time
compare active and assisted movement
track symptom response
record deviation or joint sounds
support chewing, biting and oral function assessment
decide whether related tests would add context
monitor progress after changes in symptoms, loading or function
It is most useful with:
TMJ depression
lateral jaw deviation
jaw closing control
cervical ROM
headache history
postural assessment
chewing tolerance
pain and symptom questionnaires
In Measurz, record the baseline protrusion measurement in millimetres.
Record:
active, comfortable, maximum or assisted protrusion
protrusion in millimetres
pain score
symptom location
joint sounds
jaw deviation
dental landmarks used
overjet or measurement method
client position
measurement tool
endpoint definition
stopping reason
retest date
Track progress across sessions and compare with TMJ depression, lateral deviation, cervical ROM, headache symptoms and functional notes such as chewing, speaking and biting tolerance.
TMJ Depression
TMJ Lateral Deviation
Jaw Closing Control
Cervical Flexion
Cervical Extension
Cervical Rotation
Neck Flexion Rotation C1–2
Headache Disability Index
Neck Disability Index
Postural Assessment
It measures how far the lower jaw can move forward, usually recorded as mandibular protrusion in millimetres.
Many practical references describe protrusion around 5–12 mm or 7–12 mm, but values vary by person and measurement method.
Measure how far the lower incisors move forward relative to the upper incisors, using consistent landmarks and accounting for dental alignment where needed.
Both can be useful. Active testing shows what the client can control, while assisted testing may show available movement when guided.
It means less forward jaw movement under the tested setup. It does not explain the cause by itself.
Yes. Record clicking, catching, locking, deviation, pain and symptom location.
No. It measures movement but does not diagnose the cause of jaw symptoms.
Use the same position, landmarks, measurement method, movement instruction and symptom scale across sessions.
TMJ Translation measures forward jaw movement.
The result is usually recorded as mandibular protrusion in millimetres.
Active and assisted protrusion should be labelled separately.
Broad reference values are useful, but baseline and retest comparison are often more practical.
Overjet, tooth position, pain, deviation and joint sounds should be recorded.
Measurz should capture millimetres, symptoms, jaw deviation, joint sounds, test type and progress.
The test does not diagnose jaw symptoms or explain the cause on its own.
Dworkin, S. F., & LeResche, L. (1992). Research diagnostic criteria for temporomandibular disorders: Review, criteria, examinations and specifications, critique. Journal of Craniomandibular Disorders, 6(4), 301–355.
Kropmans, T. J. B., Dijkstra, P. U., Stegenga, B., Stewart, R., & de Bont, L. G. M. (1999). Smallest detectable difference in outcome variables related to painful restriction of the temporomandibular joint. Journal of Dental Research, 78(3), 784–789.
NICE Clinical Knowledge Summaries. (2024). Temporomandibular disorders: Assessment. National Institute for Health and Care Excellence.
Shaffer, S. M., Brismée, J.-M., Sizer, P. S., & Courtney, C. A. (2014). Temporomandibular disorders. Part 1: Anatomy and examination/diagnosis. Journal of Manual & Manipulative Therapy, 22(1), 2–12. https://doi.org/10.1179/2042618613Y.0000000060
Walker, N., Bohannon, R. W., & Cameron, D. (2000). Discriminant validity of temporomandibular joint range of motion measurements obtained with a ruler. Journal of Orthopaedic & Sports Physical Therapy, 30(8), 484–492. https://doi.org/10.2519/jospt.2000.30.8.484
