Chapter 24Chapter 24

The Temporomandibular JointThe Temporomandibular Joint

OverviewOverview

The stomatognathic system comprises the The stomatognathic system comprises the temporomandibular joint (TMJ), the temporomandibular joint (TMJ), the masticatory systems, and the related masticatory systems, and the related organs and tissues such as the salivary organs and tissues such as the salivary glandsglands

Due to the proximity of this system with Due to the proximity of this system with the other structures of the head and neck, the other structures of the head and neck, an intimate relationship existsan intimate relationship exists

This relationship begins in the early stages This relationship begins in the early stages of human embryologyof human embryology

ANATOMYANATOMY

BonesBones

MandibleMandible

MaxillaMaxilla

Zygomatic archZygomatic arch

Temporal boneTemporal bone

Temporomandibular Temporomandibular JointJoint

The articular surfaces of the The articular surfaces of the temporomandibular joint are lined temporomandibular joint are lined by fibrous tissue - this reflects the by fibrous tissue - this reflects the development of the jointdevelopment of the joint

Unlike all other synovial joints Unlike all other synovial joints whose articular surfaces develop whose articular surfaces develop endochondrally and are therefore endochondrally and are therefore lined by hyaline cartilage, the lined by hyaline cartilage, the temporomandibular joint develops temporomandibular joint develops in membranein membrane

Intra-articular DiscIntra-articular Disc

Fibrous in structureFibrous in structure Divides the joint cavity into two Divides the joint cavity into two

regionsregions Thinnest centrallyThinnest centrally Attaches anteriorly to the lateral Attaches anteriorly to the lateral

pterygoidpterygoid Attaches posteriorly to the condyleAttaches posteriorly to the condyle

Joint CapsuleJoint Capsule

Capsular ligaments – fibers only Capsular ligaments – fibers only pass between the temporal bone pass between the temporal bone and mandible on the lateral sideand mandible on the lateral side

Intrinsic ligaments – short fibers Intrinsic ligaments – short fibers which pass from the bone to the which pass from the bone to the intra-articular discintra-articular disc

Ligamentous supportLigamentous support

Lateral TMJ ligamentLateral TMJ ligament

Stylomandibular ligamentStylomandibular ligament

MusclesMuscles

Lateral pterygoidLateral pterygoid• Origin – Origin –

Upper head arises from the infratemporal surface of the Upper head arises from the infratemporal surface of the greater wing of the sphenoidgreater wing of the sphenoid

Lower head arises from the lateral surface of the lateral Lower head arises from the lateral surface of the lateral pterygoid platepterygoid plate

• Insertion - The anterior aspect of the neck of the Insertion - The anterior aspect of the neck of the mandibular condyle and capsule of the TMJmandibular condyle and capsule of the TMJ

• Innervation - A branch of the mandibular division of the Innervation - A branch of the mandibular division of the trigeminal nervetrigeminal nerve

• FunctionFunction Upper head - involved mainly with chewing, and functions to Upper head - involved mainly with chewing, and functions to

anteriorly rotate the disc on the condyle during the closing anteriorly rotate the disc on the condyle during the closing movementmovement

Lower head - exerts an anterior, lateral, and inferior pull on Lower head - exerts an anterior, lateral, and inferior pull on the mandible, thereby opening the jaw, protruding the the mandible, thereby opening the jaw, protruding the mandible, and deviating the mandible to the opposite side mandible, and deviating the mandible to the opposite side

MusclesMuscles

Medial pterygoidMedial pterygoid• Origin - Deep origin situated on the medial Origin - Deep origin situated on the medial

aspect of the mandibular ramus aspect of the mandibular ramus • Insertion - The inferior and posterior aspects Insertion - The inferior and posterior aspects

of the medial subsurface of the ramus and of the medial subsurface of the ramus and angle of the mandible angle of the mandible

• Innervation - A branch of the mandibular Innervation - A branch of the mandibular division of the trigeminal nervedivision of the trigeminal nerve

• Function - Working bilaterally - assists in Function - Working bilaterally - assists in mouth closing. Working unilaterally – mouth closing. Working unilaterally – deviation of the mandible toward the deviation of the mandible toward the opposite side opposite side

MusclesMuscles

Masseter - two-layered quadrilateral shaped Masseter - two-layered quadrilateral shaped muscle. muscle. – OriginOrigin

The superficial portion arises from the anterior two-thirds of the The superficial portion arises from the anterior two-thirds of the lower border of the zygomatic archlower border of the zygomatic arch

The deep portion arises from the medial surface of the The deep portion arises from the medial surface of the zygomatic arch.zygomatic arch.

– Insertion - On the lateral surface of the coronoid Insertion - On the lateral surface of the coronoid process of the mandible, upper half of the ramus and process of the mandible, upper half of the ramus and angle of the mandibleangle of the mandible

– Innervation - A branch of the mandibular division of the Innervation - A branch of the mandibular division of the trigeminal nervetrigeminal nerve

– Function - The major function of the masseter is to Function - The major function of the masseter is to elevate the mandible, thereby occluding the teeth elevate the mandible, thereby occluding the teeth during mastication.during mastication.

MusclesMuscles

TempororalisTempororalis• Origin - The floor of the temporal fossa and Origin - The floor of the temporal fossa and

temporal fasciatemporal fascia• Insertion - On the anterior border of the Insertion - On the anterior border of the

coronoid process and anterior border of the coronoid process and anterior border of the ramus of the mandibleramus of the mandible

• Innervation - A branch of the mandibular Innervation - A branch of the mandibular division of the trigeminal nerve division of the trigeminal nerve

• Function - assists with mouth closing/side-Function - assists with mouth closing/side-to-side grinding of the teeth. Also provides to-side grinding of the teeth. Also provides a good deal of stability to the joint a good deal of stability to the joint

MusclesMuscles

DigastricDigastric– Origin - The posterior belly arises from the Origin - The posterior belly arises from the

mastoid, or digastric, notch immediately behind mastoid, or digastric, notch immediately behind the mastoid process of the temporal bone.the mastoid process of the temporal bone.

– Insertion - The posterior belly passes downwards Insertion - The posterior belly passes downwards and forwards towards the hyoid bone where it and forwards towards the hyoid bone where it becomes the intermediate digastric tendon and becomes the intermediate digastric tendon and joins with the anterior belly.joins with the anterior belly.

– Nerve Supply - derived from the digastric branch Nerve Supply - derived from the digastric branch of the facial nerve.of the facial nerve.

– Vasculature - arterial blood supply from the Vasculature - arterial blood supply from the posterior auricular and occipital arteries.posterior auricular and occipital arteries.

– Action - The muscle depresses the mandible and Action - The muscle depresses the mandible and can elevate the hyoid bone. The posterior bellies can elevate the hyoid bone. The posterior bellies act in unison and are particularly active during act in unison and are particularly active during swallowing and chewing.swallowing and chewing.

BIOMECHANICSBIOMECHANICS

BiomechanicsBiomechanics

TMJ motions involve a TMJ motions involve a combination of rolls and glides of combination of rolls and glides of the mandibular head and disc the mandibular head and disc

All TMJ motions involve all or All TMJ motions involve all or some of the following:some of the following:– Anterior/posterior glideAnterior/posterior glide– Medial/lateral glideMedial/lateral glide– Inferior/posterior glideInferior/posterior glide

Opening and closingOpening and closing

Mouth openingMouth opening– Anterior glide Anterior glide – Lateral glideLateral glide– Inferior glideInferior glide

Mouth closingMouth closing– Posterior glidePosterior glide– Medial glideMedial glide– Superior glideSuperior glide

Lateral DeviationLateral Deviation

Contralateral deviation Contralateral deviation – Anterior, inferior and lateral glide of Anterior, inferior and lateral glide of

the mandibular head and disc the mandibular head and disc Ipsilateral deviationIpsilateral deviation

– Posterior, superior and medial glide Posterior, superior and medial glide of the mandibular head and disc of the mandibular head and disc

Protrusion and Protrusion and RetrusionRetrusion ProtrusionProtrusion

– Anterior, inferior and lateral glide of Anterior, inferior and lateral glide of the mandibular head and disc the mandibular head and disc

RetrusionRetrusion– Posterior, superior and medial glide Posterior, superior and medial glide

of the mandibular head and disc of the mandibular head and disc

EXAMINATIONEXAMINATION

ExaminationExamination

As with any other synovial joint, As with any other synovial joint, there are a number of possible there are a number of possible causes/scenarios:causes/scenarios:– Local causeLocal cause– Referred causeReferred cause– Loss of motion with or without painLoss of motion with or without pain– Excessive motion with or without Excessive motion with or without

painpain

HistoryHistory

There are three cardinal features of There are three cardinal features of temporomandibular disorders (TMD): temporomandibular disorders (TMD): – Restricted jaw function (intermittent or Restricted jaw function (intermittent or

progressive)progressive)– Joint noise (significant if associated with other Joint noise (significant if associated with other

factors)factors)– Orofacial painOrofacial pain ( (Pain that is centered Pain that is centered

immediately in front of the tragus of the ear and immediately in front of the tragus of the ear and projects to the ear, temple, cheek, and along projects to the ear, temple, cheek, and along the mandible is highly-diagnostic for TMD)the mandible is highly-diagnostic for TMD)

It is important to observe the patient’s It is important to observe the patient’s mouth while they talkmouth while they talk

HistoryHistory

Attempt to determine a specific Attempt to determine a specific mechanism:mechanism:– Trauma (including surgery – “controlled Trauma (including surgery – “controlled

trauma”)trauma”)– PosturePosture– Emotional factorsEmotional factors– Parafunctional habits (cheek biting, nail Parafunctional habits (cheek biting, nail

biting, pencil chewing, teeth clenching biting, pencil chewing, teeth clenching (day), bruxism (night))(day), bruxism (night))

– Symptom-provoking motions of the TMJ or Symptom-provoking motions of the TMJ or neighboring joint(s)neighboring joint(s)

HistoryHistory

The patient’s past dental and The patient’s past dental and orthodontic historyorthodontic history

Whether the patient has Whether the patient has experienced any “locking” of the experienced any “locking” of the jawjaw

Whether the symptoms are Whether the symptoms are improving or worseningimproving or worsening

HistoryHistory

Systems reviewSystems review– Pain or dysfunction in the orofacial Pain or dysfunction in the orofacial

region can often be due to non-region can often be due to non-musculoskeletal causes:musculoskeletal causes: Otolaryngologic diseaseOtolaryngologic disease Neurologic diseaseNeurologic disease Vascular diseaseVascular disease Neoplastic, and infectious disease Neoplastic, and infectious disease Psychogenic diseasePsychogenic disease

ObservationObservation

The forward head posture is frequently The forward head posture is frequently associated with TMDassociated with TMD…..try it…..try it

A lateral deviation of the jaw, evidenced A lateral deviation of the jaw, evidenced by a malalignment or malocclusion of by a malalignment or malocclusion of the upper and lower teeth, may cause the upper and lower teeth, may cause an adaptive shortening of the an adaptive shortening of the mastication muscles on one side, and a mastication muscles on one side, and a lengthening of the mastication muscles lengthening of the mastication muscles on the contralateral side. on the contralateral side.

ObservationObservation

Cavities, wear patterns, and restored and Cavities, wear patterns, and restored and missing teeth should be notedmissing teeth should be noted– Tooth wear and fracture are often destructive Tooth wear and fracture are often destructive

signs of parafunctional habitssigns of parafunctional habits The rest position of the TMJ should be notedThe rest position of the TMJ should be noted

– The rest position of the TMJ is determined by The rest position of the TMJ is determined by gently placing the little finger with the palmar gently placing the little finger with the palmar portion facing anteriorly into the external auditory portion facing anteriorly into the external auditory meatus. From an open mouth position, the meatus. From an open mouth position, the patient is asked to slowly close their mouth. At patient is asked to slowly close their mouth. At the point of the resting position, the patient’s the point of the resting position, the patient’s mandibular heads should be felt to gently touch mandibular heads should be felt to gently touch the finger. the finger.

Range of MotionRange of Motion

The range of motion of the The range of motion of the cervical spine, craniovertebral cervical spine, craniovertebral joints and the shoulders should be joints and the shoulders should be assessedassessed

The range of motion of the neck The range of motion of the neck and jaw should then be assessed:and jaw should then be assessed:– Active range of motion with passive Active range of motion with passive

overpressure to assess the end feel. overpressure to assess the end feel.

Range of MotionRange of Motion

All movements should be smooth All movements should be smooth and without noise or painand without noise or pain– If pain occurs, a determination should If pain occurs, a determination should

be made as to where in the range the be made as to where in the range the pain occurs, and the location of the pain occurs, and the location of the painpain

The type and temporal sequence of The type and temporal sequence of joint clicking can provide the joint clicking can provide the clinician with information clinician with information

Joint NoiseJoint Noise

Reciprocal clicking is defined as Reciprocal clicking is defined as clicking that occurs during opening clicking that occurs during opening and again during closing. and again during closing. – Early clicking usually indicates a small Early clicking usually indicates a small

anterior displacementanterior displacement– Late clicking usually indicates that the disc Late clicking usually indicates that the disc

has been further displacedhas been further displaced Often due to articular hypermobility, and is Often due to articular hypermobility, and is

accompanied by a deviation of the jaw toward accompanied by a deviation of the jaw toward the contralateral side. the contralateral side.

Mouth OpeningMouth Opening

Mouth opening is the most revealing and Mouth opening is the most revealing and diagnostic movement for TMDdiagnostic movement for TMD

Normal motion tested using knuckle test Normal motion tested using knuckle test (approximately a two-three-knuckle width of the (approximately a two-three-knuckle width of the non-dominant hand) or more objectively by non-dominant hand) or more objectively by measuring (closer to 40 mm)measuring (closer to 40 mm)– A limited opening of the jaw may indicate joint A limited opening of the jaw may indicate joint

hypomobility, muscle tightness, or the presence of hypomobility, muscle tightness, or the presence of trigger points within the elevator muscles: the trigger points within the elevator muscles: the temporalis, masseter and medial pterygoidtemporalis, masseter and medial pterygoid

– Other causes of diminished mandibular opening Other causes of diminished mandibular opening include structural disorders of the TMJ, such as include structural disorders of the TMJ, such as ankylosis, internal derangements, and gross ankylosis, internal derangements, and gross osteoarthritisosteoarthritis

C and S CurvesC and S Curves

A ‘C-pattern’ of motion occurs if the A ‘C-pattern’ of motion occurs if the hypomobility is due to internal derangementhypomobility is due to internal derangement– The mandible deviates toward the involved side in The mandible deviates toward the involved side in

the midrange of opening before returning to normal. the midrange of opening before returning to normal. An ‘S-pattern’ of movement while opening the An ‘S-pattern’ of movement while opening the

mouth may indicate a muscle imbalance. An mouth may indicate a muscle imbalance. An arc may indicate a muscle imbalancearc may indicate a muscle imbalance

Lateral excursion of the mandible with mouth Lateral excursion of the mandible with mouth opening implicates contralateral structures opening implicates contralateral structures such as the contralateral disc, masseter, such as the contralateral disc, masseter, temporalis, lateral pterygoid, or the lateral temporalis, lateral pterygoid, or the lateral ligamentsligaments

PalpationPalpation

Palpation of the TMJ is used to Palpation of the TMJ is used to assess tenderness, skin assess tenderness, skin temperature, muscle tone, swelling, temperature, muscle tone, swelling, skin moisture, and the location of skin moisture, and the location of trigger pointstrigger points– Palpations of the lateral and posterior Palpations of the lateral and posterior

aspects of the temporomandibular aspects of the temporomandibular joints are performed bilaterally and joints are performed bilaterally and simultaneouslysimultaneously

Strength TestingStrength Testing

It is important to be able to It is important to be able to selectively stress the muscles of selectively stress the muscles of mastication and facial expression mastication and facial expression to determine whether they are to determine whether they are implicated in the symptomsimplicated in the symptoms

Ligament Stress TestsLigament Stress Tests

The ligament stress tests assess the The ligament stress tests assess the integrity of the capsule and integrity of the capsule and ligamentsligaments– Positive findings include excessive Positive findings include excessive

motion as compared to the other side, motion as compared to the other side, or painor pain

Two structures are primarily tested:Two structures are primarily tested:– Temporomandibular ligamentTemporomandibular ligament– Joint capsuleJoint capsule

Passive Articular Passive Articular MobilityMobility The passive articular mobility tests assess The passive articular mobility tests assess

the joint glides and the end feelsthe joint glides and the end feels– Findings are compared with each sideFindings are compared with each side– Pain or a restricted glide are positive findings and Pain or a restricted glide are positive findings and

may indicate articular involvement or a capsular may indicate articular involvement or a capsular restriction.restriction.

It is important to check the specific glides It is important to check the specific glides that are related to the loss of active motion. that are related to the loss of active motion. For example, if a patient demonstrated For example, if a patient demonstrated diminished mouth opening mouth, the diminished mouth opening mouth, the combined anterior, inferior, and lateral glide combined anterior, inferior, and lateral glide is assessed for each joint. is assessed for each joint.

Articular glidesArticular glides

Mouth opening, contralateral Mouth opening, contralateral deviation, and protrusion all involve deviation, and protrusion all involve an anterior, inferior and lateral an anterior, inferior and lateral glide of the mandibular head and glide of the mandibular head and discdisc

Mouth closing, ipsilateral deviation, Mouth closing, ipsilateral deviation, and retrusion all involve an and retrusion all involve an posterior, superior and medial glide posterior, superior and medial glide of the mandibular head and discof the mandibular head and disc

ConclusionsConclusions

If the joint glides are normal – the joint is If the joint glides are normal – the joint is OKOK– Check ligaments and surrounding tissuesCheck ligaments and surrounding tissues

If the joint glides are restricted, the cause If the joint glides are restricted, the cause could indicate a joint/joint capsule could indicate a joint/joint capsule restriction, a ligamentous adhesion or restriction, a ligamentous adhesion or adaptive shortening of the surrounding adaptive shortening of the surrounding tissues – need to mobilize the offending tissues – need to mobilize the offending joint and re-assessjoint and re-assess

The intervention should always match the The intervention should always match the diagnosis!!diagnosis!!

Articular testsArticular tests

Dynamic loadingDynamic loading– The patient bites forcefully on a cotton roll The patient bites forcefully on a cotton roll

or tongue depressor on one side. This or tongue depressor on one side. This maneuver loads the contralateral TMJ.maneuver loads the contralateral TMJ.

Joint compressionJoint compression– The clinician, standing behind the seated or The clinician, standing behind the seated or

supine patient, places the fingers of each supine patient, places the fingers of each hand under each side of the mandible, with hand under each side of the mandible, with the thumbs resting on the ramus. The the thumbs resting on the ramus. The mandible is then tipped posteriorly and mandible is then tipped posteriorly and inferiorly to compress the joint surfacesinferiorly to compress the joint surfaces

Neurological testsNeurological tests

Trigeminal sensationTrigeminal sensation Trigeminal reflexTrigeminal reflex

INTERVENTIONINTERVENTION

InterventionIntervention

Based on:Based on:– Stage of healing. Stage of healing. Chronic TMD pain Chronic TMD pain

often occurs because of secondary often occurs because of secondary factors:factors: A fixed head forward postureA fixed head forward posture Abnormal stress levelsAbnormal stress levels DepressionDepression Oral parafunctional habitsOral parafunctional habits

– Structure involvedStructure involved

Acute StageAcute Stage

The acute patient typically The acute patient typically demonstrates:demonstrates:– A capsular pattern of restriction A capsular pattern of restriction

(decreased ipsilateral opening and lateral (decreased ipsilateral opening and lateral deviation to the contralateral side), with deviation to the contralateral side), with pain and tenderness on the same sidepain and tenderness on the same side

There may be associated ligamentous There may be associated ligamentous damage (positive stress tests), or damage (positive stress tests), or muscular damage (positive strength muscular damage (positive strength tests)tests)

Acute StageAcute Stage

The usual methods of decreasing The usual methods of decreasing inflammation are recommended: inflammation are recommended: PRICEMEMPRICEMEM– PProtectionrotection– RRestest– IIcece– CCompressionompression– EElevation?levation?– MManual therapyanual therapy– EEarly motionarly motion– MMedications edications

TMJ ExercisesTMJ Exercises

Acute stage:Acute stage:– ““6x6” exercise protocol of Rocabado6x6” exercise protocol of Rocabado – Cork exerciseCork exercise– Tongue positioning during mouth Tongue positioning during mouth

opening and closingopening and closing

TMJ ExercisesTMJ Exercises

Functional Stage:Functional Stage:– Strengthening exercises for the Strengthening exercises for the

cervicothoracic stabilizers, and the cervicothoracic stabilizers, and the scapular stabilizersscapular stabilizers

– Stretching exercises for the Stretching exercises for the scalenes, trapezius, pectoralis scalenes, trapezius, pectoralis minor, and levator scapulae; and the minor, and levator scapulae; and the suboccipital extensors suboccipital extensors

Home Home (Automobilization) (Automobilization) ExercisesExercises Mouth opening exerciseMouth opening exercise Tongue depressor exerciseTongue depressor exercise Toothpick exerciseToothpick exercise Distraction mobilizationDistraction mobilization

Functional (Chronic) Functional (Chronic) StageStage Postural and patient education should Postural and patient education should

form the cornerstone of any plan of care form the cornerstone of any plan of care for TMDfor TMD

Psychotherapy referralPsychotherapy referral Manual techniquesManual techniques ExerciseExercise Thermal and electrotherapeutic Thermal and electrotherapeutic

modalitiesmodalities Trigger point therapyTrigger point therapy