TEMPOROMANDIBULAR JOINT

EXAMINATION&

ITS IMAGING MODALITIES

Chetan Basnet

BDS 4th year

Roll No: 02

ContentsIntroduction to TMJExamination

i. Clinical Evaluation Of TMJii. Clinical Evaluation Of Muscles of Masticationiii. Clinical Evaluation Of Cervical Muscles

Imaging Modalities of TMJi. Imaging of osseous structuresii. Imaging of soft tissues

TEMPOROMANDIBULAR JOINTTMJ is a ginglymo-diarthroidal joint that is freely mobile with

superior and inferior joint spaces separated by articular disc.

a term that is derived from “ginglymus” meaning a hinge joint, allowing motion

only backward and forward in one plane, and “arthrodia”

meaning a joint of which permits a gliding motion of thesurfaces .

Location of TMJTMJ are located 1.5 cm anterior to the tragus of ear. The two TMJ

considered together, comprise only one part of the total articulation between the lower jaw and the skull facial skeleton complex. The other important contribution is made by the inter-digitation of the mandibular and maxillary dentition, and function, and health of the joint is directly related to the condition of the teeth.

TMJTMJ are the two joints between the mobile mandible and a fixed

temporal bone. Each joint contain two joint spaces which are separated by a fibro cartilaginous articular disk.

Components of TMJ1. Glenoid Fossa & Articular Eminence/Protuberance2. Mandibular Condyle3. Articular Disk & Capsule4. Synovial Fluid5. Discal Ligaments6. Posterior Attachment or Retrodiscal Tissue or Bilaminar Zone7. Ligaments associated with TMJ8. Muscles of Mastication9. Arterial Supply, Venous Drainage & Sensory Innervation of TMJ

Clinical Examination of TMJBefore moving to the clinical examination of TMJ followings are to be ruled out :• The history of presenting illness should comprise of onset and course of

signs and symptoms • Past history should include the details about arthritis, infections,

degenerating diseases, parotitis, ear disorders, muscular disorders, trauma, past dental treatment, diet/nutritional adequacy, habits like clenching, chewing… etc. and the individual lifestyle.

• Then the examination is carried out through the series ofi. Inspectionii. Palpationiii. Auscultation

QUESTIONS TO BE ASKED:1. Do you have pain in the face, front of ear and the temple area?2. Do you get headaches , earaches , neckache , or cheek pain?3. When is the pain at its worst ?4. Do you experience pain when using the jaw?5. Do you experience pain in the teeth?6. Do you experience joint noises when moving your jaw or chewing?7. Does your jaw ever lock or get stuck?8. Does your jaw motion feel restricted?9. Have you had any jaw injury?10.Have you had treatment for jaw symptoms? if so , what was the effect?11.Do you have any other muscle , bone , or joint problem such as arthritis?

Inspection

1. Inspection• The face is inspected for any obvious asymmetry, scars,

swelling/ulceration/sinus openings in the pre-auricular area.• Observed for deviation/deflection of mandible on mouth while opening.• Assesment of range of mandibular movements: maximum mouth

opening , lateral movement , deviation white opening , protrusive movement

• The maximum opening distance between the incisal edges of upper and lower incisor is measured using scale , Boley gauge or ruler

• Normal opening – 40 to 55 mm

• Normal opening can also be estimated by patient’s own finger

• Normal : three finger end on end• Two finger opening reveals

reduction in opening but not necessarily reduction in function

• One finger opening indicates reduced function

LATERAL RANGE OF MOVEMENT• Normal lateral range of movement is >7mm• Measurements are made with teeth slightly seperated,measuring the

displacement of lower midline from maxillary midline.• Any condition (tumor, muscle spasm, fracture, ankylosis, displaced

meniscus) that prevents the normal translation of one condyle will not prevent the contralateral condyle from sliding forward normally . The result is deviation of the chin toward the affected side .

Examine the hands for signs of systemic disease (e .g.,• Heberden's nodes of osteo-arthrosis, ulnar deviation of rheumatoid

arthritis), which may also involve the TMJ . • Laboratory tests (e .g., complete blood count, erythrocyte sedimentation

rate, rheumatoid factor, antinuclear antibody, serum uric acid) are helpful when a systemic cause for TMJ disease is suspected.

Palpation

2. Palpation

Palpatory examination of TMJ should include the assessment of mouth opening, range of mandibular movements, joint tenderness, detection of click and/or crepitus.• The TMJ can be palpated by extra-auricular and intra-auricular methods.• Palpation can be done standing at 10 o’clock or 11 o’clock position

Intra-auricular:-Intra-auricular palpation can be achieved by placing a little finger

inside the external auditory meatus. During mandibular movement the posterior pole of the condylar head can be palpated with the pulp of the little finger. Intra-auricular palpation may also be used to elicit capsular tenderness.

Extra-auricular:-Extra auricular examination of TMJ is done by placing index finger in

the pre-auricular region about 1.5cm medial to the tragus of ear. The lateral pole of the condyle is accessible during this examination.

JOINT SOUNDSThere are 2 types of joint sound to look out for:

Clicks - single explosive noise of short duration. Crepitus - continious 'grating' noise

Auscultate TMJ noises (not routinely done)

Clinical Evaluation Of Muscles of Mastication

Tenderness to muscles of mastication results from stress and fatigue which are characteristics of temporo-mandibular dysfunction.The muscles to be examined are:

• Masseter• Temporalis• Medial Pterygoid• Lateral Pterygoid

EXAMINATION OF THE MUSCLES

• Functional disorders of the masticatory muscles are probably the most common TMD complaint of the patients seeking treatment in the dental office.

• With regard to pain , they are second to odontalgia in terms of frequency.• They are generally grouped in large category known as “masticatory muscle

disorder”

• As with any pathologic state two major symptoms can be observed:1.Pain2.dysfunction

PAIN

• Certainly the most common complaint in patients with masticatory muscle disorder is pain , which may range from slight tenderness to extreme discomfort.

• Pain felt in muscle tissue is called myalgia.• It may arise from increased level of muscle use.• Symptoms are usually associated with a feeling of muscle fatigue and

tightness.• Some authors suggest it is related to vasoconstriction of relevant nutrient

arteries and accumulation of metabolic waste products in the muscle tissue.

• Within the ischemic area of the muscle , certain algogenic substances (eg bradykinin , prostaglandins) are released ,causing muscle pain.

• Severity of muscle pain is directly related to the extent of the functional activity.

• Therefore patients always report that pain affects their functional activity.• The clinician must also remember that , myogenous pain is a type of deep

pain , and if it becomes constant, can produce central excitatory effects.• Therefore it can reinitiate more muscle pain (i.e. cyclic effect)• This clinical phenomenon was first described in 1942 as “cyclic muscle spasm” .• More recently , with the findings that the painful muscles are not truly in

spasm, the term “cyclic muscle pain” was coined.• Another very common symptom associated with masticatory muscle pain is

headache.

DYSFUNCTION

• Usually it is seen as decrease in range of mandibular movement.• When muscle tissues have been compromised by over-use , any contraction or

stretching increases the pain.• Therefore to maintain comfort , patient restricts movement within a range that

doesnot increase the pain level.• Clinically this is seen as inability to open mouth widely.

TEMPORALIS MUSCLE

It is a large fan shaped muscle that originates from temporal fossa and lateral surface of skull.

Its fibers comes downward zygomatic arch and lateral surface of the skull to form a tendon that inserts into coronoid process and anterior border of ascending ramus.

It can be divided into three distinct areas:

1. Anterior portion : consists of fibers that are direcrted vertically2. Middle portion : contains fibers that run obliquely across lateral aspect

of the skull3. Posterior portion : that are aligned almost horizontally.When temporal muscle contracts , it elevates mandible.

Anterior,Middle andPosteriorportions of thetemporalis muscleshould be palpated

Temporalis muscle can be seen and readily palpated throughout entire length and breadth when the patient’s teeth are firmly clenched.

MASSETER MUSCLE

ORIGIN:Superficial portion – anterior 2/3of lower border of zygomaticarch Deep portion – medial surface ofZygomatic arch

INSERTION: Lateral surface of ramus,Coronoid process, and angle ofmandible

FUNCTION: Elevates mandible, clenches teeth

Palpate multiple areas ofthe masseter muscle

As with temporalis muscle, it can be located when patient’s jaw are forcibly closed. the body of masseter can be palpated with thumb and index finger. index finger can palpate the entire body of masseter.

MEDIAL PTERYGOID / INTERNAL PTERYGOID

ORIGIN:Medial surface of lateral pterygoid plate and tuberosity of maxilla and can not be palpated

INSERTION:lower medial surface of ramus of mandible

FUNCTION:Elevation and protraction

• Anterior part of insertion can be palpated by placing the finger at 45 degrees in the floor if the patients mouth near base of the relaxed tongue.

• The opposite hand can be used to extra-orally to palpate posterior and inferior portions of insertion.

• Body of the muscle can be palpated by rotating the index finger upwards against the muscle to near its origin on the tuberosity.

LATERAL / EXTERNAL PTERYGOID

ORIGIN:It originates in two parts:Superior head from the greater wing of sphenoidInferior head the lateral surface of the pterygoid plate

INSERTION:Neck of condyle and articular

disc of TMJ.

FUNCTION:protraction

PALPATION OF LATERAL PTERYGOID MUSCLE

The muscle is palpated by using the little or index finger and placing it lateral to maxillary tuberosity and medial to coronoid process. The finger presses upwards and inwards and a painful response can be determined .

• Demonstration of the lateral pterygoid’s attachment anterior articular disc has led to the theory that some anterior disc displacements may be related to its dysfunction.

• Hyperactivity of the muscle is capable of pulling the disc forward from its normal position.

Clinical Evaluation Of Cervical Muscles

STERNOCLIEDOMASTOID MUSCLEThe sternocleidomastoid passes obliquely across the side of the neck.It is thick and narrow at its central part, but broader and thinner at either end.

medial or sternal head , which arises from the upper part of the anterior surface of the manubrium sterni , and is directed superiorly, laterally, and posteriorly.

lateral or clavicular head arises from the superior border and anterior surface of the medial third of the clavicle ; it is directed almost vertically upward.

DIGASTRICORIGIN

anterior belly - digastric fossa (mandible) posterior belly - mastoid process of temporal bone

INSERTION: Intermediate tendon (hyoid bone)

ACTION:When the digastric muscle contracts, it acts to elevate the hyoid bone.If the hyoid is being held in place), it will tend to depress the mandible (open the mouth).

The SCM is effectively palpated on each side of the neck when the patient moves the head to the contralateral side

PALPATION OF THE MUSCLES

Diagnostic Imaging Of TMJ

The type of imaging technique depends upon the

clinical problems associated, so either imaging of hard tissue (OSSEOUS) or soft tissue is desired.Certain protocols are to be taken care before the imaging procedure: the amount of diagnostic information available from

particular imaging modality. The cost of examination The radiation dose

NOTE:- when selecting the imaging modality the strength and weakness of each imaging modality should be considered.

Diagnostic Imaging Of TMJ

IMAGING OF TMJ

OSSEOUES STRUCTURES1. Panoramic Projection2. Plain Film Imaging Modalities3. Conventional Tomography 4. Computed Tomography (CT)

SOFT TISSSUE STRUCTURES1. Arthrography2. Magnetic Resonance Imaging (MRI)

IMAGING OF OSSEOUS

STRUCTURES

Panoramic Projections

The panoramic projection is often included as a part of examination as it provides an overall view of the teeth and the jaws, provides a means of comparison between left and right sides of mandible, serves as screening projections to identify certain odontogenic diseases, certain disorders that may be source of TMJ symptoms

Panoramic machines have specific TMJ programs which are of limited usefulness. Thick image layers Oblique view/distorted view of the joints Low image quality

However this imaging modality gives a gross osseous change of condyle such as:-AsymmetriesExtensive erosionsLarge osteophytesTumors Fractures

However panoramic projections doesn’t provide information's about condylar positions or function as the mandible is partly opened or protruded when radiograph is exposed.Mild osseous changes may be obscured, and only marked changes in articular eminence morphology can be seen as a result of super imposition by the skull base and zygomatic arch.

For these reasons, the panoramic view should not be considered as a sole in imaging modality and be supplemented.

Plain Film Imaging Modalities

Plain Film Imaging Modalities

The plain film usually consists of combinations of following projections and allows visualization in various planes:- Transcranial Projections Transpharyngeal Projections Transorbital Projections Submentovertex Projections

TRANSCRANIAL PROJECTION

TRANSCRANIAL VIEW

It is a view that aids in visualizing the sagittal view of the lateral aspects of condyle and temporal

component. It is taken in both open and close mouth positions.

Film position: • flat against patients ear• Centered over TM joint of interest• Against facial skin parallel to sagittal plane

Position of patient: head adjusted so sagittal plane is vertical &

ala tragus line parallel to floorView :

3 positions- open, close, rest mouth

Central Ray1. the central ray is direct at an angle of 250(+ve

angulation) from the opposite side, through the cranium and above the petrous ridge of the temporal bone.

2. The horizontal angulation can be individually corrected for the condylar long axis, or an average 200 anterior angle may be used.

Closed view- size of joint space, position of head of condyle, shape & condition of glenoid fossa & articular eminenceOpen view- range & type of movementComparison of both sides

Disadvantages :• Superimposition of ipsi-lateral petrous ridge over the

condylar neck

Transcranial projections of the left TMJ. degree of translatory movement between the closed view (A) and the

open view(B)

(A) (B)

Transpharyngeal View

Transpharyngeal View(Parma projection, Macqueen-Dell Technique)

This technique provides a sagittal view of the medial pole of the condyle. It is taken in open mouth position.

Film placement-patient holds the cassette flat against patients earCentered over TM joint of interestAgainst facial skin parallel to sagittal plane½ inch anterior to EAM

Position of patient- Occlusal plane parallel to transverse axis of film-soft

parts are in a line with nasopharynx and joint.

Patient instructed to inhale slowly through nose, filling of

nasopharynx with air

Open mouth-condyles move away from base of skull and

mandibular notch is enlarged on opp side.

Central ray-

directed from opp side cranially at angle(-5 to -10 degrees)

Beneath the zygomatic arch, through sigmoid notch

posteriorly across pharynx at the condyle

Comparison of both condylar heads

Parma modification

Lead lined open ended cone is removed and tube head is brought closer to skin surface producing magnification of structure reducing superimposition

Transorbital Projections(ZIMMER

PROJECTION)

It is taken in the open or protruded position and depicts the entire medial lateral aspect of condyle in frontal plane.

Transorbital Projections

Film position- behind patients head at an angle of 45 degree to sagittal

panePosition of patient-

-sagittal pane vertical-Canthomeatal line should be 10 degree to the horizontal with head tipped downwards

Central ray--tube head-front of patients face-directed to joint of interest at an angle of +20 degrees to strike cassette at right angles

Point of entry may be taken as-- Pupil of the same eye-asking patient to look straight ahead- Medial canthus of the same eye

Disadvantage : if the patient cannot open wide, areas of the joint articulating surfaces will be obscured because of mutual superimposition

Condyle seen below articular eminence

Submentovertex Projections

Submentovertex Projections

A submentovertex projections provides a view of skull base and condyles in a horizontal plane. It is often used to determine the angulations of the long axis of the condylar head so for corrected tomography.

Conventional Tomography

Conventional Tomography(CT)

CT provides more information about the 3- Dimensional shapes and internal structures of the osseous components of joints by providing detailed image slices and 3D images.Two types of CT are available:-

1. Conventional CT2. CBCT

Both modalities can give excellent image of osseous structures, but only conventional CT can give images of surrounding soft tissues.

….

Tomography is a radiographic technique that produces multiple thin image slices, permitting visualization of the osseous structures essentially free of super-impositions of overlapping.

This technique can provide multiple image slices at right angles through the joint depicting true condylar position revealing the osseous changes. However conventional tomography is gradually being replaced by CONE-BEAM COMPUTED TOMOGRAPHY.

NOTE:-Tomographs typically are exposed in sagittal

(lateral) planes corrected to the condylar long axis, with several image slices in closed (maximal inter-cuspation) position and usually one image in maximal open position

It is desirable to supplement sagittal images with coronal (frontal) tomographs particularly when morphologic abnormalities or erosive changes of condylar head are suspected.

Computed Tomography

CBCT is the recent technology developed for

angiography in 1982 and subsequently applied to maxillofacial imaging.

CBCT has the advantage of reduced patient overdose compared to medial CT and is likely to replace Conventional Tomography. In CBCT the patient is scanned in closed position and low resolution scan done in open or other positions.

Data from the axial slices can be manipulated

to produce corrected lateral and frontal images of the TMJ. PANOROMIC and 3-D reformatted images can also be produced. These are useful for assessing osseous deformities of the jaws or surrounding structures.

NOTE:- Conventional and CBCT can not produce accurate images of the articular disk.

Three-dimensional shape and internal structure

of the osseous components Surrounding soft tissue Both axial & coronal images Reformat images in sagittal plane Not diagnostic for disk

…

Indications:

Extent of ankylosis neoplasms-bone involvement Complex fractures Complications -polytetrafluoroethylene or silicon

sheet implants -erosions into the middle cranial fossa

Heterotopic bone growth

DIRECT SAGITTAL CT SCANS

3 scans/joint-closed, half, open-2mm slice thicknessNeck bent- 45 to 55 degree so that the plane of ramus is parallel to the imaging

plane

Soft Tissue Structures Imaging

Soft tissue imaging is indicated when the TMJ pain and dysfunction are present and when clinical findings suggest disk displacement along with symptoms that arte unresponsive to conservative therapy. Imaging should be prescribed only when the anticipated results are expected to influence the treatment plan.

The imaging modalities for soft tissues are:1. Arthrography2. Magnetic Resonance Imaging (MRI)

Arthrography

ArthrographyNorgaard (1940)

It is a technique in which an indirect image of the disk is obtained by injecting a radiopaque contrast agent into the joint spaces under fluoroscopic guidance.

However MRI has replaced Arthrography in todays context and is now the imaging technique of choice for soft tissues.

Indications: Position and function of disk -pain and dysfunction-long standing

History of locking-persistent

Perforations of the disk and retrodiskal tissue.

Joint dynamics

Disc displacement-ant/anteromedial

Contraindications:Infections in the preauricular region.Patients allergic to contrast media.Patients with bleeding disorders and on anticoagulant therapy

Contrast Media Arthroscopes

Arthroscopic sheath

Arthroscopic biopsy

• Vascular injury• Extravasation of

irrigation fluid into the surrounding tissue

• Broken instruments in the joint

• Intracranial damage• Infection• Nerve injury

Complications

MAGNETIC RESONANCE IMAGING

(MRI)

Uses Magnetic field and radiofrequency pulses Tissue with greater water content emit a higher signal Bilateral dual surface coils- 0.5 to 2 tesla-Improve image

resolution MRI produces excellent image qualities so is the

principle imaging choice for soft tissue.

Oblique sagittal/oblique coronal scans with t1, t2

Closed mouth, partially open and fully open positions

images in the sagittal and coronal planes without repositioning the patient

T1-weighted images best –osseous & diskal tissues T2-weighted images- inflammation and joint

effusion. Motion MRI studies-during opening and closing the

patient open in a series of stepped distances and using rapid image acquisition. ("fast scan ")

Disk is of low signal intensity (dark grey or black) and can be distinguished from surrounding tissue that has high signal intensity.

Posterior disk attachment (PDA) shows higher than the disk and the junction between the posterior band of the disk and PDA is distinct.

Medial disk displacements-best seen

NOTE:- It is contraindicated in patient who are pregnant or have pacemakers, intra-cranial vascular clips, or metal particles in vascular structures. Some patients may be unable to tolerate the procedure due to claustrophobia( or inability to remain motionless.)

MRI of a normal TMJ. A. Closed view showing the condyle and temporal component. The biconcave disk is

located with its posterior band (arrow) over the condyle.

B. Coronal image showing the osseous components and disk (arrows) superior to the condyle.

A. B.

This sagittal MR image shows anterior disk displacement in the closed mouth position. Disc is deformed

Advantages of CT

Direct delineation of bony structures-surgical anatomy

Reconstruction in all planes

Some soft tissues-lateral pterygoid muscle

3-D images from any angle

Disadvantages--high radiation exposure-soft tissues cant be

appreciated

Advantages of MRI

Soft tissues-esp disk and its association

Information in short acquisition time

Disadvatages--expensive-claustophobia

References Oral Radiology- 6th edition

Stuart C. White, Michael J. Pharoah Burket’s Oral Medicine – 11th edition

Giclk , Ship, Greenberg, Textbook Of Oral Medicine Oral Diagnosis and Oral

Radiology- 2nd edition Ravikiran Ongole, Praveen B N

Other Sources- Internet, Google, Wikepedia

THANK YOU