Transcript The Temporomandibular Joint

Chapter 24
The Temporomandibular Joint
Overview
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The stomatognathic system comprises the
temporomandibular joint (TMJ), the
masticatory systems, and the related organs
and tissues such as the salivary glands
Due to the proximity of this system with the
other structures of the head and neck, an
intimate relationship exists
This relationship begins in the early stages
of human embryology
ANATOMY
Bones
Mandible
Maxilla
Zygomatic arch
Temporal bone
Temporomandibular Joint
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The articular surfaces of the
temporomandibular joint are lined by
fibrous tissue - this reflects the
development of the joint
Unlike all other synovial joints whose
articular surfaces develop
endochondrally and are therefore lined
by hyaline cartilage, the
temporomandibular joint develops in
membrane
Intra-articular Disc
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Fibrous in structure
Divides the joint cavity into two
regions
Thinnest centrally
Attaches anteriorly to the lateral
pterygoid
Attaches posteriorly to the condyle
Joint Capsule
Capsular ligaments – fibers only pass
between the temporal bone and
mandible on the lateral side
Intrinsic ligaments – short fibers
which pass from the bone to the intraarticular disc
Ligamentous support
Lateral TMJ ligament
Stylomandibular ligament
Muscles
Lateral pterygoid
• Origin –
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Upper head arises from the infratemporal surface of the greater wing
of the sphenoid
Lower head arises from the lateral surface of the lateral pterygoid
plate
• Insertion - The anterior aspect of the neck of the mandibular
condyle and capsule of the TMJ
• Innervation - A branch of the mandibular division of the
trigeminal nerve
• Function
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Upper head - involved mainly with chewing, and functions to
anteriorly rotate the disc on the condyle during the closing
movement
Lower head - exerts an anterior, lateral, and inferior pull on the
mandible, thereby opening the jaw, protruding the mandible, and
deviating the mandible to the opposite side
Muscles
Medial pterygoid
• Origin - Deep origin situated on the medial
aspect of the mandibular ramus
• Insertion - The inferior and posterior aspects of
the medial subsurface of the ramus and angle of
the mandible
• Innervation - A branch of the mandibular division
of the trigeminal nerve
• Function - Working bilaterally - assists in mouth
closing. Working unilaterally – deviation of the
mandible toward the opposite side
Muscles
Masseter - two-layered quadrilateral shaped
muscle.
– Origin
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The superficial portion arises from the anterior twothirds of the lower border of the zygomatic arch
The deep portion arises from the medial surface of the
zygomatic arch.
– Insertion - On the lateral surface of the coronoid
process of the mandible, upper half of the ramus
and angle of the mandible
– Innervation - A branch of the mandibular division
of the trigeminal nerve
– Function - The major function of the masseter is
Muscles
Tempororalis
• Origin - The floor of the temporal fossa and
temporal fascia
• Insertion - On the anterior border of the
coronoid process and anterior border of the
ramus of the mandible
• Innervation - A branch of the mandibular division
of the trigeminal nerve
• Function - assists with mouth closing/side-toside grinding of the teeth. Also provides a good
deal of stability to the joint
Muscles
Digastric
– Origin - The posterior belly arises from the mastoid, or
digastric, notch immediately behind the mastoid process
of the temporal bone.
– Insertion - The posterior belly passes downwards and
forwards towards the hyoid bone where it becomes the
intermediate digastric tendon and joins with the anterior
belly.
– Nerve Supply - derived from the digastric branch of the
facial nerve.
– Vasculature - arterial blood supply from the posterior
auricular and occipital arteries.
– Action - The muscle depresses the mandible and can
elevate the hyoid bone. The posterior bellies act in
unison and are particularly active during swallowing and
chewing.
BIOMECHANICS
Biomechanics
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TMJ motions involve a combination of
rolls and glides of the mandibular head
and disc
All TMJ motions involve all or some of
the following:
– Anterior/posterior glide
– Medial/lateral glide
– Inferior/posterior glide
Opening and closing
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Mouth opening
– Anterior glide
– Lateral glide
– Inferior glide
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Mouth closing
– Posterior glide
– Medial glide
– Superior glide
Lateral Deviation
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Contralateral deviation
– Anterior, inferior and lateral glide of the
mandibular head and disc
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Ipsilateral deviation
– Posterior, superior and medial glide of the
mandibular head and disc
Protrusion and Retrusion
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Protrusion
– Anterior, inferior and lateral glide of the
mandibular head and disc
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Retrusion
– Posterior, superior and medial glide of the
mandibular head and disc
EXAMINATION
Examination
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As with any other synovial joint, there
are a number of possible
causes/scenarios:
– Local cause
– Referred cause
– Loss of motion with or without pain
– Excessive motion with or without pain
History
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There are three cardinal features of
temporomandibular disorders (TMD):
– Restricted jaw function (intermittent or
progressive)
– Joint noise (significant if associated with other
factors)
– Orofacial pain (Pain that is centered immediately
in front of the tragus of the ear and projects to
the ear, temple, cheek, and along the mandible
is highly-diagnostic for TMD)
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It is important to observe the patient’s
mouth while they talk
History
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Attempt to determine a specific mechanism:
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Trauma (including surgery – “controlled trauma”)
Posture
Emotional factors
Parafunctional habits (cheek biting, nail biting,
pencil chewing, teeth clenching (day), bruxism
(night))
– Symptom-provoking motions of the TMJ or
neighboring joint(s)
History
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The patient’s past dental and
orthodontic history
Whether the patient has experienced
any “locking” of the jaw
Whether the symptoms are improving
or worsening
History
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Systems review
– Pain or dysfunction in the orofacial region
can often be due to non-musculoskeletal
causes:
Otolaryngologic disease
 Neurologic disease
 Vascular disease
 Neoplastic, and infectious disease
 Psychogenic disease
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Observation
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The forward head posture is frequently
associated with TMD…..try it
A lateral deviation of the jaw, evidenced by
a malalignment or malocclusion of the upper
and lower teeth, may cause an adaptive
shortening of the mastication muscles on
one side, and a lengthening of the
mastication muscles on the contralateral
side.
Observation
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Cavities, wear patterns, and restored and
missing teeth should be noted
– Tooth wear and fracture are often destructive
signs of parafunctional habits
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The rest position of the TMJ should be
noted
– The rest position of the TMJ is determined by
gently placing the little finger with the palmar
portion facing anteriorly into the external
auditory meatus. From an open mouth position,
the patient is asked to slowly close their mouth.
At the point of the resting position, the patient’s
mandibular heads should be felt to gently touch
Range of Motion
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The range of motion of the cervical
spine, craniovertebral joints and the
shoulders should be assessed
The range of motion of the neck and
jaw should then be assessed:
– Active range of motion with passive
overpressure to assess the end feel.
Range of Motion
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All movements should be smooth and
without noise or pain
– If pain occurs, a determination should be
made as to where in the range the pain
occurs, and the location of the pain
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The type and temporal sequence of
joint clicking can provide the clinician
with information
Joint Noise
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Reciprocal clicking is defined as clicking that
occurs during opening and again during
closing.
– Early clicking usually indicates a small anterior
displacement
– Late clicking usually indicates that the disc has
been further displaced
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Often due to articular hypermobility, and is
accompanied by a deviation of the jaw toward the
contralateral side.
Mouth Opening
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Mouth opening is the most revealing and
diagnostic movement for TMD
Normal motion tested using knuckle test
(approximately a two-three-knuckle width of
the non-dominant hand) or more objectively
by measuring (closer to 40 mm)
– A limited opening of the jaw may indicate joint
hypomobility, muscle tightness, or the presence
of trigger points within the elevator muscles: the
temporalis, masseter and medial pterygoid
– Other causes of diminished mandibular opening
include structural disorders of the TMJ, such as
ankylosis, internal derangements, and gross
C and S Curves
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A ‘C-pattern’ of motion occurs if the
hypomobility is due to internal derangement
– The mandible deviates toward the involved side
in the midrange of opening before returning to
normal.
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An ‘S-pattern’ of movement while opening
the mouth may indicate a muscle
imbalance. An arc may indicate a muscle
imbalance
Lateral excursion of the mandible with
mouth opening implicates contralateral
structures such as the contralateral disc,
Palpation
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Palpation of the TMJ is used to assess
tenderness, skin temperature, muscle
tone, swelling, skin moisture, and the
location of trigger points
– Palpations of the lateral and posterior
aspects of the temporomandibular joints
are performed bilaterally and
simultaneously
Strength Testing
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It is important to be able to selectively
stress the muscles of mastication and
facial expression to determine whether
they are implicated in the symptoms
Ligament Stress Tests
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The ligament stress tests assess the
integrity of the capsule and ligaments
– Positive findings include excessive motion
as compared to the other side, or pain
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Two structures are primarily tested:
– Temporomandibular ligament
– Joint capsule
Passive Articular Mobility
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The passive articular mobility tests assess
the joint glides and the end feels
– Findings are compared with each side
– Pain or a restricted glide are positive findings
and may indicate articular involvement or a
capsular restriction.
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It is important to check the specific glides
that are related to the loss of active motion.
For example, if a patient demonstrated
diminished mouth opening mouth, the
combined anterior, inferior, and lateral glide
is assessed for each joint.
Articular glides
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Mouth opening, contralateral
deviation, and protrusion all involve an
anterior, inferior and lateral glide of
the mandibular head and disc
Mouth closing, ipsilateral deviation,
and retrusion all involve an posterior,
superior and medial glide of the
mandibular head and disc
Conclusions
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If the joint glides are normal – the joint is
OK
– Check ligaments and surrounding tissues
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If the joint glides are restricted, the cause
could indicate a joint/joint capsule
restriction, a ligamentous adhesion or
adaptive shortening of the surrounding
tissues – need to mobilize the offending
joint and re-assess
The intervention should always match the
diagnosis!!
Articular tests
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Dynamic loading
– The patient bites forcefully on a cotton roll or
tongue depressor on one side. This maneuver
loads the contralateral TMJ.
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Joint compression
– The clinician, standing behind the seated or
supine patient, places the fingers of each hand
under each side of the mandible, with the
thumbs resting on the ramus. The mandible is
then tipped posteriorly and inferiorly to
compress the joint surfaces
Neurological tests
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Trigeminal sensation
Trigeminal reflex
INTERVENTION
Intervention
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Based on:
– Stage of healing. Chronic TMD pain often
occurs because of secondary factors:
A fixed head forward posture
 Abnormal stress levels
 Depression
 Oral parafunctional habits
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– Structure involved
Acute Stage
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The acute patient typically demonstrates:
– A capsular pattern of restriction (decreased
ipsilateral opening and lateral deviation to the
contralateral side), with pain and tenderness on
the same side
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There may be associated ligamentous
damage (positive stress tests), or muscular
damage (positive strength tests)
Acute Stage
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The usual methods of decreasing
inflammation are recommended: PRICEMEM
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Protection
Rest
Ice
Compression
Elevation?
Manual therapy
Early motion
Medications
TMJ Exercises
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Acute stage:
– “6x6” exercise protocol of Rocabado
– Cork exercise
– Tongue positioning during mouth opening
and closing
TMJ Exercises
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Functional Stage:
– Strengthening exercises for the
cervicothoracic stabilizers, and the
scapular stabilizers
– Stretching exercises for the scalenes,
trapezius, pectoralis minor, and levator
scapulae; and the suboccipital extensors
Home (Automobilization)
Exercises
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Mouth opening exercise
Tongue depressor exercise
Toothpick exercise
Distraction mobilization
Functional (Chronic)
Stage
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Postural and patient education should form
the cornerstone of any plan of care for TMD
Psychotherapy referral
Manual techniques
Exercise
Thermal and electrotherapeutic modalities
Trigger point therapy