Download temporomandibular joint

TEMPOROMANDIBULAR
DISORDERS – LECTURE SERIES
ANATOMICAL
CONSIDERATIONS
Clinical A/P Chua Ee Kiam - BDS, MDS, FAMS, Dip (Counselling)
Pain
unpleasant sensory & emotional experience
assoc with actual / potential tissue damage,
&/ described in terms of such damage
Loeser et al, 2001; Merskey H et al, 1994; Portenoy et al, 1996
TYPES OF PAIN
1. Nociceptive pain is caused by stimulation of
peripheral nerve fibers that respond to noxious
stimulation
2. Neuropathic pain is caused by damage or disease
affecting the central or peripheral nervous system
3. Phantom pain is pain from a part of the body that has
been lost or from which the brain no longer receives
signals
4. Psychogenic pain is pain caused, increased, or
prolonged by mental, emotional, or behavioral factors
CHRONIC PAIN
persistent / recurrent pain,
lasting beyond usual course of
acute Illness/injury,
/>6 mths,
& adversely affecting pat’s wellbeing
Loeser et al, 2001; Merskey H et al, 1994; Portenoy et al, 1996
• Pain is expressed with gestures and facial expression
Gender differences
• Females are more affected than males
• Pain is high when oestrogen is low
• Common pain conditions, including migraine and tensiontype headache, facial pain, and abdominal pain, indicate
higher prevalence rates in adult women than in adult
men.
Gender variations in clinical pain experience- Unruh A
Pain 65:123-167, 1996
IMPORTANCE OF PAIN
1. Makes one withdraw from potentially damaging
situations
2. Protect a damaged body part while it heals
3. Trains one to avoid painful situations in the
future
PAIN FACTS
1. Most pain resolves promptly once the painful
stimulus is removed
2. Some pain persists despite removal of the
stimulus
3. Sometimes pain arises in the absence of any
detectable stimulus, damage or disease
The Pain Gate Control Theory
NO INPUT –
GATE IS
CLOSED
Gate Control Theory was initially proposed in 1965 by Melzack and Wall that a gating
mechanism exists in the dorsal horn of the spinal cord. Small nerve fibers (pain receptors)
and large nerve fibers (“normal receptors”) synapse on the the substantia gelatinosa and
Thalamus (which goes to the brain)
When no input comes in, the SG prevents T from sending signals to the brain (gate is
closed)
The Pain Gate Control Theory
NORMAL INPUT –
GATE IS CLOSED
Normal somatosensory input happens when there is more large-fiber stimulation. Both the
SG and the T are stimulated, but the SG prevents T from sending signals to the brain
(gate is closed).
GATE CONTROL THEORY
Nociception (pain reception) happens when there is more small-fiber stimulation
or only small-fiber stimulation. This inactivates the SG ; T sends signals to the
brain informing it of pain (gate is open).
The Pain Gate Control Theory
chemicals
+/-
Chemicals released as a response to the pain stimuli also influence whether
the gate is open or closed for the brain to receive the pain signal. This lead to
the theory that the pain signals can be interfered with by stimulating the
periphery of the pain site.
The Pain Gate Control Theory
-
touch
It is generally recognized that the 'Pain gate' can be shut by stimulating
nerves responsible for carrying the touch signal (mechanoreceptors) which
enables the relief of pain through massage techniques, rubbing, and also the
application of ice packs.
MUSCLE PAIN (MYALGIA)
Muscle pain can involve more than one muscle and also
involve ligaments, tendons, and fascia, the soft tissues
that connect muscles, bones, and organs.
Muscle pain also can be a sign of flu infections affecting
your whole body and disorders that affect connective
tissues throughout the body (SLE).
CAUSES OF MUSCLE PAIN
Injury or trauma
Overuse: using a muscle too much,
too soon, too often
Tension or stress
Drugs (Cocaine & Statins for lowering
cholesterol)
Infections (Flu, Malaria)
Systemic Disorders (Lupus)
DIAGNOSIS I
1.
2.
3.
4.
5.
6.
7.
ARTHRALGIA
MYALGIA
SPLINTING
TRAUMATIC TRISMUS
CONTRACTURE
DISC DISPLACEMENT WITH
REDUCTION
DISC DISPLACEMENT WITHOUT
REDUCTION
DIAGNOSIS II
1.
2.
3.
4.
5.
6.
7.
8.
TENDONITIS
LATERAL CAPSULITIS
RETRODISCITIS
SUBLUXATION
DISLOCATION
OSTEOARTHROSIS
OSTEOARTHRITIS
ARTHRITIS
Osteoarthrosis - The cartilage covering bones (articular cartilage) is thinned, eventually completely
worn out, resulting in a "bone against bone" joint, reduced motion and pain.
Osteoarthritis - the joints exposed to high stress ; pain is experienced
MAIN MUSCLES OF MASTICATION
•
•
•
•
•
Masseter
Temporalis
Medial Pterygoid
Lateral Pterygoid
all innervated by mandibular division of the Trigeminal Nerve
MUSCLES OF MASTICATION
MASSETER
Origin: zygomatic bone
Attachment:
lateral surface of angle &
ramus of mandible
Action: closes jaw
deep masseter
- vertical force
superficial masseter
- vertical & slightly anterior force
perpendicular to occlusal plane of molars
MUSCLES OF MASTICATION
TEMPORALIS
Origin: temporal fossa
Attachment:
coronoid
Action: anterior fibres - close jaw
posterior fibres - retract
DIAGNOSIS
TENDONITIS
 complaint of pain on function
 pain on palpation of tendon attachments
 anaesthetic block eliminates the pain
MUSCLES OF MASTICATION
MEDIAL
PTERYGOID
Origin: pterygoid fossa
Attachment: medial surface of
angle of mandible
Action: closes jaw and moves
mandible to opposite side
MUSCLES OF MASTICATION
LATERAL PTERYGOID
• Superior Pterygoid (LPS)
Origin: infratemporal surface
Attachment: capsule, disc & condylar neck
Action: stays active during power stroke and
closing
MUSCLES OF MASTICATION
LATERAL PTERYGOID
• Inferior Pterygoid (LPI)
Origin:
lateral pterygoid plate
Attachment: neck of condyle
Action:
protrudes the mandible
stays active during opening
NECK MUSCULATURE
• Sternonucleidomastoid
• Trapezius
• Intrinsic Neck Muscles
MUSCLE PAIN & INJURY
MYALGIA
- subjective complaint of pain in the muscles
- tenderness on palpation
- if more diffuse - it is called fibromyalgia*
• EMG studies
Franks, 1965, Schwartz, 1968, Stohler, 1985, Yemm, 1971
• Thermography
Berry, 1974, Kopp, 1981
*Fibromyalgia include widespread musculoskeletal pain, severe fatigue, and disturbed sleep.
DIAGNOSIS
SPLINTING
 guarded jaw opening
 due to co-contraction of muscles as a means
to avoid pain
 can be due to reflex splinting due to
behavioural factors
DIAGNOSIS
TRAUMATIC TRISMUS
 limited range of motion
 passive stretch - no significant increase
 can be CNS - induced
DIAGNOSIS
CONTRACTURE
 chronic resistance of a muscle to passive
stretch
 a result of fibrosis of supporting tendons,
ligaments and muscle fibers
 usually caused by trauma
 can be due to infection
 irradiation
FORCES OF MASTICATION
1. Force (Brekhus et al, 1941)
Males
Females
= 53.6 to 64.4 kg
= 35.8 to 44.9 kg
2. Range of maxillary force on incisor & molar
1st molars
= 41.3 to 89.8 kg
Central Incisors = 13.2 to 23.1 kg
3. Grinding phase (Gibbs et al, 1981)
Closure stroke averaged 26.7 kg
(Howell & Manly, 1948)
TEMPOROMANDIBULAR JOINT
TMJ is a freely movable joint
consisting of the condyle, fossa and a
disc that divides into superior and
inferior cavities. These cavities are
filled with synovial fluid.
Upper compartment - gliding
movements
Lower compartment - hinge
movements
Sensory innervation –
Auriculotemporal & masseteric
branches of V3 of Trigerminal Nerve
From SOTO USA
TEMPOROMANDIBULAR JOINT
ARTHRALGIA
 complaint of joint pain
 joint tenderness on palpation
TEMPOROMANDIBULAR JOINT
•
•
•
•
•
•
•
•
Condyle
Fossa
Disc
Articular surface
Disc Attachments
Capsule
Accessory Ligaments
Synovial tissues
TEMPOROMANDIBULAR JOINT
CONDYLE
LATERAL VIEW: IRREGULAR CONVEX
LONG AXIS:
right angle to plane of ramus
Long axes of R & L condylar heads meet anterior
of foramen magnum at 140 - 160 degrees
TEMPOROMANDIBULAR JOINT
CONDYLE
SIZE :
Anterior to posterior = 8 -10mm
Medial to lateral= 15-20mm
FRONTAL VIEW: TENT-SHAPED
Lateral pole – is attached TM ligament &
lateral part of disc
Medial pole - is attached only to the disc
CONTOUR:
AP - very convex ; ML - gently convex
Top
Front
TEMPOROMANDIBULAR JOINT
CONDYLE POSITION
Concentricity
- 50-65% prevalence
Non-concentricity - posterior (more females)
- anterior (more males)
Treatment positions for diagnosis and treatment options
- Disc displacements
- Reposition therapy
- 4/7 position proposed by Gelb
TEMPOROMANDIBULAR JOINT
CONDYLE
1.
Superior and anterior surfaces are articulating areas
2.
Form of condylar depends on thickness of CT
(Pullinger, Bibb et al; OSOMOP, 1993)
3.
Thicker layers thought to be associated with higher
loads
4.
Condylar asymmetry between R & L are significant
in both M & F (Costa RL; Am J Phys Anthropol; 1986)
5.
Condylar head is rounder in young than adults
TEMPOROMANDIBULAR JOINT
GLENOID OR MANDIBULAR FOSSA
anterior wall- squamous temporal
posterior wall- tympanic plate
thin roof – precludes loading
Functional part is the ARTICULAR FOSSA
- entirely of squamous temporal bone and covered by
articular tissue
TEMPOROMANDIBULAR JOINT
ARTICULAR FOSSA - entirely of squamous temporal
bone and covered by articular tissue
1. Irregular and does not uniformly conform to the shape of
the condylar head
2. Variations in form is independent to shape of condylar head
(Solberg et al JOR, 1985)
3. Larger mesiolaterally than anteroposteriorly
4. Bordered anteriorly by post. slope of articular eminence
5. Bordered posteriorly by postglenoid tubercle (this separates
the EAM from TMJ)
6. Bordered medially and superiorly by temporal bone
TEMPOROMANDIBULAR JOINT
ARTICULAR SURFACES
- are covered with fibrous connective tissue instead of
hyaline cartilage
(Fibrous Connective Tissue has high tensile strength. It is found
in tendons and ligaments and composed of large amounts of
closely packed collagenous fibers)
-thickest at anterior superior of condyle and posterior inferior
slope of the eminence
- thickness varies 0.1 to 0.5mm
TEMPOROMANDIBULAR JOINT
Cartilage is classified in three types –elastic, hyaline and fibrocartilage
Unlike other connective tissues, cartilage does not contain blood vessels
hence it heals very slowly
Hyaline cartilage
- rich in collagen and proteoglycan
- form the smooth articular surface of joints
- found in larynx, nose, between ribs and sternum
Elastic cartilage
- contains large amounts of elastic fibers (elastin)
- stiff yet elastic
- found in ear (pinna), epiglottis and Eustachian tube
Fibrocartilage
- characterized by a dense network of Type I collagen (most abundant in
body)
- tough material that provides high tensile strength and support
- contains more collagen and less proteoglycan than hyaline cartilage
- present in areas most subject to frequent stress like intervetebral discs,
symphysis pubis and the attachments of certain tendons and ligaments.
Proteoglycans - (are glycoproteins ) occur in connective tissues of humans
Collagen – main protein in CT in animals
.
TEMPOROMANDIBULAR JOINT
DISC
SHAPE: Ellipsoid
FUNCTION:
Support stabilization of condyle against articular eminence
COMPOSITION:
Collagen fibers
Superior & inferior fibers - anterior- posterior oriented fibers
Central portion fibers
- oriented in all 3 directions of space
POSITION: the posterior band is at the superior crest of the condyle
DISC
The disc functions as articular surfaces
against both the temporal bone and the
condyles and divides the joint into two
compartments
It is bi-concave in structure and attaches to
the neck of the condyle medially and
laterally (and not to capsule or lateral
ligaments
Anterior portion of disc coincides with the
insertion of the superior head of the lateral
pterygoid
Between the posterior portion and the
posterior lamina is the “vascular knee”
Application: Disc surgery to reduce
displaced Discs?
DIAGNOSIS
RETRODISCITIS
 Inflammation of retrodiscal tissues
condyle may be forced posteriorly
 retrodiscal tissues may swell forcing the
condyle forward - acute malocclusion
with heavy contact on contra-lateral
anterior teeth

DIAGNOSIS
DISC DISPLACEMENT WITH
REDUCTION
 reproducible joint noise
 pain may be precipitated on jaw
movement
 soft tissue imaging reveal the displaced
disc
DIAGNOSIS
DISC DISPLACEMENT WITHOUT REDUCTION
 marked limited mandibular opening & pain
 deviation to affected side on opening
 marked limited laterotrusion to contralateral side
 no joint noise
 soft tissue imaging reveal the displaced disc
LOCKED
TEMPOROMANDIBULAR JOINT
DISC DISPLACEMENTS
- usually in antero-medial direction
- posterior lamina is brought into articulation
- conversion into a dense pad by metaplasia
- or lead to clicks, locks or degenerative
disease
TEMPOROMANDIBULAR JOINT
CAPSULE
(outer - fibrous membrane)
(inner – synovial membrane)
ATTACHMENT
• lower-loosely attached to condyle on
medial & lateral
• upper - lateral tip of glenoid fossa on
lateral & sphenoid bone on medial
• well organized posterior wall which
blends with the disc
• thickened laterally to form the TM
ligament
• anterior aspect of joint - medial 1/2
no capsule
• lateral 1/2 loose CT
TEMPOROMANDIBULAR JOINT
Lateral ligaments
Major ligament
Temporomandibular ligament is
thickened lateral part of capsule
Minor ligaments
Stylomandibular ligament
Sphenomandibular ligament
FUNCTION
The ligaments define the border
movements of the mandible
APPLICATION - Dislocation
Hinge Motion / Rotation
The inferior compartment allows for rotation of the condylar
head around with the first 20-25 mm of the opening of the
mouth.
Translation
Beyond that, the superior compartment comes into play to
allow for translation and maximum opening
TEMPOROMANDIBULAR JOINT
SYNOVIAL TISSUES
ATTACHMENT : To disc
SUPERIOR CAVITY (1.2 ml) - anterior and posterior villi folds allow
for translation as much as 2 cm
INFERIOR CAVITY (0.9ml) - villi allows disc to rotate posteriorly as
condyle rotate forward
SYNOVIAL FLUID - lubricant and consist of hyaluronic acid (aids
in shock absorption and transportation of nutrients), synovial cells
& defence cells
Application 1- Fluid Analysis: Interleukin-1B (Kubota et al, 1977)
This cytokine has the potential to initiate events that lead to loss of
articular tissue, bone and cartilage
Application 2 – Jaw stuck after clenching
TEMPOROMANDIBULAR JOINT
APPLICATION
CAPSULE
SURGICAL IMPLICATIONS
• Dissection of capsule lateral to condyle leads
to the superior cavity
• Dissection of the disc leads to the inferior
cavity
• suturing disc to capsule will tense disc to the
lateral lip of the glenoid fossa so disc is
deflected to the lateral pole and limit
translation
DIAGNOSIS
LATERAL CAPSULITIS
 tenderness at lateral pole of condyle
 usually follows trauma incident
 continuous pain originating from joint
area
REMODELLING OF THE
TEMPOROMANDIBULAR JOINT
i. Progressive remodelling
ii. Regressive remodelling
iii. Peripheral remodelling
Osteophytes and sclerosis is part of the
remodelling process
Johnson, 1959; Solberg, 1985; Moffet, 1964; Blackwood, 1966
REMODELLING OF THE
TEMPOROMANDIBULAR JOINT
1.
Progressive remodelling adds new bone
due to proliferation of articular cartilage
and mineralization
2.
Regressive remodelling causes
osteoclastic resorption of subchondral
bone to be filled by mesenchymal bone
and replaced by cartilage, bone or both
3.
Peripheral remodelling occurs at margin
of articular cartilage
BIOMECHANICS OF THE
TEMPOROMANDIBULAR JOINT
BASIC MOVEMENTS
1.
Hinge movement –rotation of mandible around
transverse axis passing through the centers of
condyles
(occurs in lower joint compartment between disc
and condyle)
2.
Sliding movement- bodily movement of mandible
in anteroposterior and/or mediolateral direction
(upper joint compartment between articular
eminence and disc)
BIOMECHANICS OF THE
TEMPOROMANDIBULAR JOINT
INITIAL OPENING PHASE
1-2 Disc rotates posteriorly aided by
tension in posterior attachment &
inactivty of sup. lateral pterygoid
Disc-condyle moves downwards
3
At mid open, joint is passive and
unstressed
BIOMECHANICS OF THE
TEMPOROMANDIBULAR JOINT
FULL OPENING PHASE
3
Gliding of disc is maximum
CLOSING OR POWER STROKE
4
Superior part of lat pterygoid
active-tenses disc and cause it to
move forward
Disc form s “moving wedge” to
ensure full contact between joint
components
BIOMECHANICS OF THE
TEMPOROMANDIBULAR JOINT
FULL CLOSURE PHASE
4-1 Disc is rotated forward
Disc is stabilized by posterior
attachment