Muscles of mastication / dental courses

MUSCLES
OF
MASTICATION
INDIAN DENTAL
ACADEMY
Leader in continuing Dental
Education
www.indiandentalacademy.com

INTRODUCTION
• Muscle can be defined as organ / tissue that by
contraction produces movement of an animal
• 100’s to 1000’s of motor units ,blood vessels, nerves
bundled together by connective tissue and fascia
make up a muscle

• Mastication is defined as the act of chewing foods.
It represents the initial stage of digestion, when
food is broken down into small particle sizes for
the ease of swallowing.
• Precise movement of mandible by muscles of
mastication is required to move teeth efficiently
across each other during mastication

10 to 80
micrometer
Made up of
myofibrils
Ends of muscle
fibers fuses to
form tendon
which inserts
into bone

ACCORDING TO AMOUNT OF
MYOGLOBIN
Type 1/ slow fibers
• High myoglobin conc
• deep red in colour
• Well dev aerobic
metabolism ,
• capable of
slow,sustained
contraction,
• resistant to fatigue
Type 2/ fast fibers
• Low myoglobin
• Whiter
• Few mitochondria,
relay on anaerobic
metabolism
• Capable of quick
contraction
• Fatigue more rapidly

MOTOR UNIT

• Basic component of neuromuscular system
• Consists of no of muscle fibers innervated by one
motor neuron
• Each motor neuron joins with muscle fiber at end
plate
• Activation of neuron – motor end plate is stimulated
to release small amounts of acetyl choline which
initiates depolarisation of muscle fibers
• This cause muscle fibers to shorten/contract

• No of muscle fibers innervated by a motor neuron
varies greatly according to function
• In ciliary muscles which precisely controls lens of eye
2 0r 3 muscle fibers are supplied by a nerve
• In contrast hundreds of muscle fibers are supplied by
a nerve in leg

• Inf lateral pterygoid has relatively low muscle
fiber/neuron ratio
• It is capable of fine adjustments in length needed to
adapt horizontal changes in mandibular position
• Masseter has greater motor fibers per motor neuron
which corresponds to its more gross function of
providing force necessary during mastication.

MUSCLE FUNCTION
• When large no of motor units in muscle are
stimulated
• Leads to contraction/overall shortening of muscle
• This type of shortening under constant load is called
isotonic contraction
• Occurs in masseter when mandible is elevated
forcing teeth through a bolus of food

• When a proper No of motor units contract opposing
a given force, the resultant function of muscle is to
hold/stabilise jaw
• This type of contraction without shortening is called
isometric contraction
• Occurs in masseter when an object is held between
teeth

• A muscle also can function through controlled
relaxation
• When stimulation of motor unit is discontinued
fibers of motor unit relax and return to normal
length
• By control of decrease in motor stimulation a precise
muscle lengthening can occurs that allows smooth,
delibrate movement

PRIMARY MUSCLES OF MASTICATION
1. Masseter
2. Temporalis
3. Lateral pterygoid
4. Medial pterygoid
 Develop from the mesoderm of the 1st brachial arch.
 Supplied by the Mandibular nerve

MASSETER
 Quadrilateral
 Covers lateral surface of
ramus of mandible.
 Three layers
1. superficial layer [largest]
2. middle layer
3. deep layer

MASSETER
1.SUPERFICIAL LAYER (LARGEST)
:
 ORIGIN:
Anterior 2/3rd of lower
border of zygomatic arch &
adj. zygomatic process of
maxilla
 FIBRES:
Passes downwards &
backwards at 45 degrees.

MASSETER
INSERTION
Lower part of the
lateral surface of
the ramus of
mandible.

2. MIDDLE LAYER :
• ORIGIN :
From anterior 2/3rd of deep
surface & posterior 1/3rd of
lower border of zygomatic
arch.
• FIBRES :
Passes vertically downwards.
• INSERTION :
Middle part of ramus of the
mandible. www.indiandentalacademy.com

3. DEEP LAYER :
 ORIGIN:
Deep surface of zygomatic arch.
 FIBRES:
Passes vertically downwards.
 INSERTION:
Upper part of ramus & coronoid
process of mandible.

ACTIONS:
• Contraction of masseter , Elevates mandible ,and teeth
are brought into contact
• Powerful muscle, that provides the force necessary to
chew efficiently.
• Superficial portion may also aid in Protruding the
mandible.
• When mandible is protruded & biting force is applied
the fibers of deep portion stabilise condyle against
articular eminence

NERVE SUPPLY:
Masseteric nerve, a branch of anterior
division of mandibular nerve

RELATIONS
SUPERFICIAL:
Skin
Platysma
Risorius
Zygomaticus major
Parotid gland
Muscle is crossed by
parotid duct
Branches of facial nerve
Transverse facial
vessels


RELATIONS
DEEP:
• Temporalis – lower part
Mandibular ramus
Masseteric nerve & artery
• A mass of fat separates it in
front from buccinator & buccal
nerve
POSTERIOR MARGIN:
Overlapped by parotid gland.
ANTERIOR MARGIN:
Projects over buccinator & is crossed
by facial nerve

TEMPORALIS
• Fan shaped muscle,
fills the temporal
fossa.
ORIGIN:
• Whole of the temporal
fossa except the part
formed by zygomatic
bone.
• Deep surface of
temporal fascia. www.indiandentalacademy.com

TEMPORALIS
FIBRES:
Converge & descends into a
tendon which passes thro the
gap between zygomatic arch &
side of skull.
Anterior fibres -- oriented
vertically.
Posterior fibres – horizontally.
Intermediate fibres -- obliquely

TEMPORALIS
INSERTION:
• Margins & deep surface of coronoid process,
• Anterior border of the ramus of mandible almost to last molar.
NERVE SUPPLY:
• Two deep temporal branches from anterior division of
mandibular nerve.

RELATIONS
SUPERFICIAL :
• Skin
• Auricularis anterior &
superior
• Temporal fascia
• Superior temporal
vessels
• Auriculo temporal
nerve
• Temporal branches of
facial nerve
• Zygomatic arch
• Masseter

RELATIONS
DEEP:
• Temporal fossa
• Lateral pterygoid
• Superficial head of medial
pterygoid
• A small part of buccinator
• Maxillary artery & its deep
temporal branches
• Deep temporal nerves
• Buccal nerve & vessels

ACTIONS
• Contraction of the muscle Elevates the
mandible & teeth are brought into contact.
Anterior fibers : Mandible raised vertically
Middle fibers : Elevate & retrude
mandible
Posterior fibers : Retrude the mandible
Contributes to side- to- side grinding movements.
• Superficial part : rich in type II B (FF) fibers
• Deep part : type I (S) fibers

Action :
• Elevates mandible
Post fibers retract
protruded mandible

LATERAL PTERYGOID
( Pterygoideus lateralis , External pterygoid)

SUPERIOR LATERAL
PTERYGOID/UPPER HEAD
• Origin
• Infra temporal surface & infra temporal crest
of the greater wing of sphenoid bone.
• Insertion
• Pterygoid fovea of the mandible,(60 to 70%)
• Articular disc,(30 to 40%)
• Capsule of the T.M.J

• Sup. Lp is inactive during mouth opening
• It is active during power stroke
• Power stroke: movement that involves closure
of mandible against resistance such as
chewing/clenching the teeth together
• add

INFERIOR LATERAL PTERYGOID/
LOWER HEAD
Origin at Lateral surface of lateral pterygoid plate
• Extends backwards,upward,outward to insert into
neck of condyle
• Action:
• Rt,lft inf lp contract simultaneously , condyles are
pulled down the articular eminence and mandible is
protruded.

• Unilateral contraction leads to mediotrusive
movement of that condyle and cause a lateral
movement of condyle to opposite side
• When this muscle functions with mandibular
depressors, mandible is lowered and condyles glide
forward & downward on articular eminence.

• The pull of pterygoids on disc & condyle is in a
significantly medial direction
• As condyle moves forward, medial angulation of this pull
becomes greater
• In wide opening muscle pull is more medial than anterior
• Approx 80% of fibers that make up lp are type 1( slow)
• So they are resistant to fatigue, may serves to brace
condyle for longer periods of time without difficulty

Action:
1) Depresses mand to
open mouth with
Supra hyoid muscle

The combinded efforts of the Digastrics and Lateral Pterygoids
provide for natural jaw opening.

• 2) Lat & med Pterygoids
 acting together 
protrude mand

3. Med & lat
Pterygoids 
contract
alternately  side
to side movts (
chewing)

MEDIAL ( internal) PTERYGOIDORIGIN:
A. SUPERFICIAL HEAD (SMALL SLIP) :
Lateral surface of the
pyramidal process & maxillary
tuberosity.
B. DEEP HEAD (QUITE LARGE)
Medial surface of the lateral
pterygoid plate & the
grooved surface of the
pyramidal process of the
palatine bone.
FIBRES:
Runs downwards, backwards &
laterally.

INSERTION:
• Attached by a strong tendinous
lamina to the postero inferior
part of the medial surface of the
mandibular ramus & angle, as
high as mandibular foramina &
almost as forward as the
mylohyoid groove.
• NERVE SUPPLY:
A branch from the mandibular
nerve.

RELATIONS
SUPERFICIAL:
Separated from lateral
pterygoid muscle & ramus of
mandible by:
Lateral pterygoid plate
Maxillary artery
Inferior alveolar vessels &
nerves
Lingual nerve
Spheno mandibular ligament
Process of the parotid gland
separated from masseter by
lower part of the ramus of
mandible

RELATIONS
DEEP:
Is related to
Tensor veli palatini,
Medial pterygoid plate
Separated from
superior constrictor by
styloglossus
stylopharyngeus
stylohyoid ligament

ACTIONS:
• Elevates the mandible.
• Acting with lateral pterygoid, it protrudes
the mandible.
• When the medial & lateral pterygoids of one
side act together, the corresponding side of
mandible is rotated forwards to the opposite
side, with the opposite mandibular head as a
vertical axis.
• Alternating activity in the left & right sets of
muscles produces side-to-side movements,
which are used to triturate food.www.indiandentalacademy.com

MEDIAL PTERYGOID

Accessory muscles of mastication
• Digastric
• Mylohyoid
• Geniohyoid
• Buccinator

Digastric muscle
• Anterior belly: digastric fossa of mandible
• Posterior belly: mastoid notch on medial side of
base of mastoid process
• Insertion :
• Both heads meet at
intermediate tendon
which perforates
stylohyoid muscle
and is held by a fibrous
pulley to hyoid bone

DIGASTRIC MUSCLE
NERVE SUPPLY :
ANTERIOR BELLY:
• Mylohyoid nerve, a branch of the mandibular division of trigeminal
nerve
POSTERIOR BELLY:
• Nerve from posterior auricular branch of facial nerve
ACTIONS :
• Depress and retract the mandible, so assisting the lateral pterygoid
muscle in opening the mouth
• Elevation of the hyoid bone, utilized during swallowing and speech

MYLOHYOID
• Flat, triangular muscle.
• Two mylohyoids forms floor of mouth
• Situated just below the anterior belly of
digastric muscle
ORIGIN :
• Mylohyoid line of mandible, extends from symphysis in front
to last molar tooth behind
INSERTION :
• Posterior fibers : Body of hyoid bone
• Middle & anterior fibers : median raphe between mandible &
hyoid bone

Superior view

inferior view

MYLOHYOID
• Fibers Runs medially & slightly downwards
• NERVE SUPPLY :
Mylohyoid nerve, a nerve from mandibular division of the
trigeminal nerve
• ACTION :
Elevates floor of mouth in deglutition
Depress the mandible & Elevates hyoid bone

GENIOHYOID
• Short & narrow muscle
• Lies above medial part of mylohyoid
muscle
ORIGIN : Inferior mental spine
FIBRES : Runs backwards & downwards
INSERTION : Anterior surface of body of hyoid bone
NERVE SUPPLY By fibers from 1st cervical nerve via hypoglossal.N
ACTION :Elevates hyoid bone, Depress mandible

BUCCINATOR

BUCCINATOR
ORIGIN :
• Upper fibers, from maxilla, opposite molar teeth
• Lower fibers, from mandible, opposite molar teeth
• Middle fibers, from pterygomandibular raphe
INSERTION :
• Upper fibers – Upper lip
• Lower fibers – Lower lip
• Middle fibers – Decussate before passing to lips
ACTION :
• Flattens cheek against gums & teeth
• Prevents accumulation of food in the vestibule.www.indiandentalacademy.com

MUSCLES RESPONSIBLE FOR MOVEMENTS OF
MANDIBLE

Palpation of muscles
of mastication

Palpation of masticatory muscles
Temporalis

Masseter

Lateral pterygoid

Medial pterygoid

Digastric

CENTRAL PATTERN GENERATOR
• These are pool of neurons in brain stem that controls
rhythmic muscle activities
• Such as breathing, walking, chewing
• Responsible for precise timing of activity between
antagonist muscles , so that specific functions can be
carried out
• Once an efficient chewing pattern that mimises any
structure to damage is found , it is learnrd, repeated…this
is called muscle engram

ROLE OF MUSCLES OF MASTICATION
IN BIOMECHANICS OF TMJ
Stability of TMJ is maintained by
• Interarticular pressure(exerted by mm)
• Morphology of disc
• The articular surfaces must be maintained in
constant contact
• Elevator group of muscles(masseter, temporalis,
medial pterygoid)

• Even in resting state, these muscles are in a mild
state of contraction/tonus
• Disc is attached anteriorly to superior lateral
pterygoid
• Disc is attached posteriorly to retrodiscal
tissues(superior lamina is made of elastic fibers)
• Sup lamina is the only structure capable of retracting
disc posteriorly on condyle.

• This retractive force is only present during wide
opening movements
• so in closed mouth position(tonus) of sup lateral
pterygoid dominates elastic traction of superior
retrodiscal lamina
• Disc is positioned slight anteriomedial …i.e..condyle
will be in contact with intermediate & posterior
zones of disc

• This disc relationship is maintained during minor
passive rotational & translational mandibular
movements
• During wide opening superior retrodiscal lamina
greater than tonus of sup lp ,then disc is positioned
posteriorly to the position permitted by width of
articular disc space
• Again during rest it is repositioned as forward as far
as disc space will permit.

POWER STROKE:
• During unilateral chewing when patient bites on hard
substance on one side
• TMJ’s are not equally loaded
• This occurs because of force of closure is not applied
to joint, but instead applied to food
• Jaw is fulcrumed around hard food
• Contralateral joint….sudden inc in interarticular
pressure
• Ipsilateral joint…..dec in interarticular
pressure….separation between articular
surfaces…may lead to dislocation

• Sup lp becomes active during power stroke
• It rotates disk forward over condyle so that thick
posterior border of disk maintains contact
• Therefore joint stability is maintained during
powerful chewing stroke.

Masticatory muscle
disorders

muscular disorders by clark (1989)
• Myalgia
• Muscle contracture
• Splinting
• Spasm
• Hypertrophy
• Dyskinesia
• Forceful jaw closure habit
• Myositis

By American Academy of Orofacial Pain
(AAOP)
Masticatory Muscle disorders
• Myofascial pain
• Myositis
• Spasm
• Protective Splinting
• Contracture

Myalgia :
• Pain is most common complaint of patients with
masticatory muscle disorder
• Range from slight tenderness to extreme discomfort
• Due to increased muscle use leading to fatigue
• Vc of relevant nutrient arteries…leading to
accumulation of metabolic wastes…ischemia of
muscles…release of algogenic substances
(bradykinin, prostaglandin)are released caused
muscle pain

• Muscle pain associated with TMD does not seems to
corelate with inc activity such as spasm
• Severity of muscle pain is directly related to
functional activity of muscles
• MYOGENOUS PAIN is a type of deep pain & it is
constant
• Can produce central excitatory effects

Central excitatory effects on muscles
of mastication
• Certain input into CNS such as deep pain can
create excitatory effect on non associated
interneurons
• When afferent interneurons involved
• referred pain
• Secondary hyperalgesia
• Efferent interneurons
• Trigger points
• Protective co-contraction

Continuous
deep pain
accumulation of
nt at synapse
Nt spills over
other inter
neurons
Referred
pain

• Convergence:
• Many incoming neurons may synapse on a single inter
neuron
• This Single interneuron may be one of several inter
neurons that converge to synapse with next ascending
interneuron
• Under normal conditions cortex interprets this
information excellently
• But in case of continuous deep pain can confuse cortex
• Result is Perception of pain in normal
structures…(heterotopic pain/referred pain)

• Secondary hyperalgesia:
• Increased sensitivity of tissues without a local cause
• Common location is scalp
• Pts with deep pain often complains that their hair
hurts
• It is different from referred pain la block of source
does not immediately arrest symptoms

Protective co-contraction
• First response of masticatory muscles to ay
event
• Also called protective muscle splinting
• It is a cns response to injury/threat of injury
• Normal sequencing of muscle activity seems
to be altered to protect threatened part from
further injury

• During opening of mouth depressor muscles are
activated & elevators are relaxed.
• But in presence of deep constant pain
• Cpg cause co activation of antagonistic muscles(
elevators)
• So that degree of mouth opening is reduced
• It is not a pathologic process
• But if prolonged it leads to muscle pain
• Pain becomes self perpetuating- Cyclic muscle pain

Trigger points
• localized spot of tenderness in a nodule of a
palpable taut band of contractured muscle fibers
• Present in muscle, tendon or both
• Felt as taut bands on palpation and elicit pain
• Trigger points may be active (induce clinical
symptoms)
• latent, only induce pain on stimulation.
• muscle overload may activate latent trigger points

• Certain nerve endings in muscle tissue becomes
sensitised by algogenic substances
• There may be local rise in temperature at site of
trigger point
• Suggesting increase in metabolic demand
• Reduction of blood flow
• Few motor units of muscle contract
• No overall shortening of muscle

HOW TRIGGER POINT GOT ITS NAME ?
• Stimulation is like pulling trigger of gun
• Immediate response
• Produces effects in another place – the target
• Cause and effect phenomenon

Trigger points may be
• associated with a twitch response when
stimulated.
• trigger point palpation may also provoke a
characteristic pattern of regional referred pain
• The area to which pain is referred is called as
ZONE OF REFERENCE
Also associated with autonomic symptoms

Areas of referred pain may include
• perioral and intraoral (teeth) structures and
depend on
• the muscles involved and the intensity of pain
• Referral to the teeth may be prominent and
may often cause misdiagnosis as dental
pathology.

Electromyographic Findings
• “spontaneous electrical activity,” and intermittent
spikes (100-600microvolts)
• The electrical activity was only present in sites of
active MTrPs
• And was absent in adjacent non-tender muscle tissue

PAIN REFERENCE POINTS FOR MASSETER MUSCLES
(TRIGGER POINTS)
SUPERFICIAL LAYER MIDDLE LAYER
LOWER DEEP

PAIN REFERENCE POINTS FOR TEMPORALIS (TRIGGER
POINTS)
MIDDLE FIFRESANTERIOR FIFRES
MIDDLE FIFRES POSTERIOR FIFRESwww.indiandentalacademy.com

PAIN REFERENCE POINTS FOR MEDIAL PTERYGOID
(TRIGGER POINTS)
BEFORE AND AFTER REMOVAL OF CONDYLE

PAIN REFERENCE POINTS FOR LATERAL PTERYGOID
(TRIGGER POINTS)
BEFORE AND AFTER REMOVAL OF SUPERFICIAL MASSETER

STERNAL DIVISION CLAVICULAR DIVISION
PAIN REFERENCE POINTS FOR STERNOCLEIDO-
MASTOID (TRIGGER POINTS)

PAIN REFERENCE POINTS FOR TRAPEZIOUS (TRIGGER
POINTS)
UPPER RIGHT TRAPEZIUS

DYSFUNCTION
• Common clinical symptom associated with
mmdisorder
• Seen as decrease in range of mandibular movement
• Overuse of muscle…compromises its
function…leading to pain while contraction/
streching
• So to maintain comfort, patient restricts movement
within this range
• Clinically seen as reduced mouth openingwww.indiandentalacademy.com

• Acute malocclusion is another type of dysfunction
• Refers to any change in occlusal condition that has
been created by a disorder.
• May result from sudden change in resting length of
muscle that controls jaw position
• Slight shortening of inferior lateral pterygoid will
cause disocclusion of posterior teeth on ipsilateral
side and premature contact of anterior teeth

• With functional shortening of elevator muscles , pt
complains of inability to occlude normally
• Acute malocclusion is result of muscle order not
cause
• Therefore treatment should be directed towards
eliminating muscle disorder rather than correcting
malocclusion.

Atrophy of Muscle
• Disuse & fixation
• Aging & cachexia
• Denervation
• Muscular dystrophies
• Nutritional disturbances
• Vascular changes
• Muscular hypotonias

Hypertrophy
• Most common involves masseter, temporalis
• Mmh is benign increase in size of masseter
• Unilateral/bilateral
• Affects both males & females
• Etiology unknown
• Due to increased muscle activity
• Bruxism, clenching due to stress
• Malocclusion, tmds
• Chronic chewing habits

Chronic muscle pain in hyperactivity
• occlusal interference/stress
• induce hyperactivity and
• spasm of the affected muscle,
• leads to ischaemia secondary to
blood vessel compression.
• Ischaemic contractions are painful
and activate muscle nociceptors

Masticatory muscle model

Event : various events can interrupt muscle function
Local:
• fractured tooth/ restoration in supraocclusion
• Trauma to local structures- injury caused by injection
• Excessive/unaccustomed use of masticatory structures
• Like chewing hard food
• Chewing for long period of time
• Opening mouth too widely may strain
ligaments/muscles
• Due to prolonged dental procedure/yawning

• Systemic:
• Emotional stress increase muscle activity
• Stress alters muscle function through either gamma
efferent system to muscle spindles or by means of
sympathetic activity to muscle tissues
• Constitutional factors like age, gender reduces pts
resistance to combat with these challenges like
• Age , gender, diet, genetic predisposition

Local muscle soreness/non inflammatory myalgia
• First response of muscle to protective co contraction
• Other causes: trauma
• Excessive muscle use
• Represents a condition characterised by changes in
muscle environment
• Cause release of algogenic substances like
(histamine, bradykinin, substance p)

• Clinically: tender muscles on palpation
• Increased pain with function
• Involvement of elevators cause co-contraction
• Represents a condition of actual muscle weakness
• E.g: if a pts mp is injured during ianb
• Leads to muscle soreness( deep pain)
• Cause co-contraction( deep pain)-Leads to cyclic pain
• Even original pain resolved due to tissue repair
• Pain still persists

CNS
EFFECTS
Chronic myalgia
disorders
Regional myofascial
pain,chronic centrally
mediated myalgia
Systemic myalgia
fibromyalgia
Acute myalgia
disorders
myospasms

Myospasm/tonic contraction myalgia:
• Acute , sudden involuntary tonic contraction
• Involving muscles of mastication is rare
• All motor units contract, resulting in spasm
• Causes: deep pain, alteration in local electrolyte balance,
muscle fatigue
• Clinical features: pain which was dull,continuous
• Limited mouth opening
• Structural changes create acute malocclusion

• Muscle spasm of the masseter and lateral
pterygoid associated with excessively wide opening
of mouth results in lock jaw in dislocated position.
• This results in inability to close the jaw. (This
dislocation can be reduced by downward pressure on
the posterior teeth forcing the condyle downward
and upward pressure on the chin slipping the
condyle backward into place)

• Treatment:
• Analgesics
• Moist heat fomentation
• If due to parafunctional habits: occlusal bite
guards

Myofascial pain of Masticatory muscles
Myofascial trigger point pain
Defined as
Regional myogenous pain condition
characterised by local areas of firm, hypersensitive
bands of muscle tissue known as trigger points

HISTORY
• Travell & Rinzler first described Myofascial
trigger point pain in 1952
• Schwartz (1956) coined the term TMJ pain
dysfunction syndrome
• Laskin (1969) implicated psycho physiologic
theory stating that the psychological stress leads
to Myospasm & described MPD syndrome

RDC for the clinical TMD conditions
I a - Myofascial pain without limited mouth opening
• Pain in masticatory muscles ( of jaw, temple,
face,preauricular area/ inside ear) at rest/ function
• Pain on palpation in atleast 3 sites( total 20)
10 sites on each side:
• Ant, middle, posterior fibers of temporalis
• Tendon of temporalis
• Origin,body,insertion of masseter
• Posterior mandibular region
• Submandibular region
• Lateral pterygoid

I b - Myofascial pain with limited mouth opening
• Myofascial pain
• Pain free unassisted opening < 40 mm
• ( INTER INCISAL DISTANCE – ANT.OPEN BITE, IID +
OVER BITE)
• passive stretch > 5mm( examiners index & thumb are
used to stetch)

Laskin’s Criteria
• Four cardinal signs and symptoms
– Pain
– Muscle tenderness
– Clicking or popping noise in TMJ
– Limitation of jaw movement - unilateral or bilateral
• Typical negative signs
– Absence of clinical, radiographical or biochemical evidence
of organic changes in the joint
– Lack of tenderness in the joint when it is palpated through
the external auditory meatus

YOU CANNOT SUCCESSFULLY
TREAT DYSFUNCTION
UNLESS YOU UNDERSTAND
FUNCTION

REFERENCES
• BD CHAURASIA’S HUMAN ANATOMY VOL.3 4TH
EDITION
• JEFFREY P. OKESON MANAGEMENT OF
TEMPOROMANDIBULAR DISORDERS AND
OCCLUSION 5TH EDITION
• Burkets Textbook Of Oral Medicine 11th Edition

Muscles of mastication / dental courses

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