The temporomandibular joint (TMJ) is a complex joint that connects the mandible to the temporal bone. It is composed of the articular disc, articular surfaces, ligaments, and muscles. The TMJ is unique in that it allows for both rotational and translational movements. Common disorders of the TMJ include dislocations, ankylosis, and temporomandibular joint dysfunction syndrome. Radiographic views like the transcranial and transorbital views are used to evaluate the TMJ.

1. TMJ (Temporo Mandibular Joint)
“Joint Of The Law”

2. CONTENTS
 Introduction
 Joint and Types of joints
 Peculiarity of TMJ
 Development of TMJ
 Components of TMJ
 Blood and Nerve supply to TMJ
 Biomechanics/Movements of TMJ
 Age changes in TMJ
 Clinical examination of TMJ
 Clinical anatomy and TMJ disorders
 Christensen’s TMJ implant
 Conclusion

3. INTRODUCTION
 Why it is called temporomandibular joint????
 What are the other names???
Craniomandibular joint
Most complex joint in the body.
Compound joint.
Ginglymoarthroidal joint.
Modified ball and socket joint.
 Most important functions of TMJ are….????
 Unique in that it constitutes of two separate joints anatomically a
Ref: WILLIAMS PL:GRAY’S ANATOMY IN SKELETALSYSTEM;38TH ed;pg:578

4. JOINT AND TYPES OF JOINTS
 Classification of joints
 FIBROUS JOINTS (SYNARTHROSES)
1.SUTURES
2.SYNDESMOSES
3.GOMPHOSES
 CARTILAGINOUS JOINTS (AMPHIARTHROSES)
1. SYNCHONDROSES (Hyaline cartilage)
2.SYMPHYSES (Fibrocartilage)
 SYNOVIAL JOINTS (DIARTHROSES)
1.UNIAXIAL
(A)GINGLYMUS (Hinge)
(B)TROCHOID (Pivot)

5. 2.BIAXIAL
(A)CONDYLOID
(B)SADDLE
3.TRIAXIAL
(A)BALL AND SOCKET
(B)PLANAR
Unique in that it constitutes of two separate
joints anatomically and they function
together as a single unit

6. PECULIARITY OF TMJ
 Bilateral diarthrosis
 Articular surface covered by white fibrous cartilage
instead of hyaline cartilage.
 Only joint in human body that have a rigid end point
,due to closure of teeth making occlusal contact
 In contrast to other diarthroidal joints,TMJ is last to
devolop( i.e., in about 7th week of uterine life)
 TMJ devolops from distinct blastema.

7. DEVELOPMENT OF TMJ
 Early TMJ develops from the first
branchial arch mesenchyme and is
therefore innervated by fifth cranial
nerve. This is the early embryonic
joint.
 This early embryonic joint is the
joint between malleus and incus
which develops from first branchial
arch.
 This joint serves as the primary
TMJ joint up to 16 weeks of
prenatal life. This joint is an
uniaxial hinge joint capable of no
lateral motion.

8. Development…..
 By the end of 7-11 weeks of
gestation,the secondary TMJ
begins to devolop .
 i.e., At about 9th week – a
condensation of
mesenchyme appears
surrounding the upper
posterior surface of
rudimentary ramus( joint
capsule devolops from the
condensed mesenchyme)
 At about 12 th week of IUL,2
clefts appear in that
mesenchyme - producing
the upper and lower joint
cavities.

9. Development…..
 The remaining intervening mesenchyme – becomes
the intra articular disc.( which will be well defined by
16th week of IUL)
 At birth – mandibular fossa( in temporal bone) is flat,
with out any articular eminence, this becomes
prominent only after the eruption of deciduous
dentition.

10. RELATIONS OF TMJ
 Laterally –
skin,fascia , parotid gland ,
Temporal branches of 7th
cranial nerve
 Medially – Tympanic plate
seperates TMJ from internal
carotid artery,spine of
sphenoid with upper end of
sphenomandibular
ligament,Auriculotemporal
and chorda tympani
nerve,Middle meningeal
artery

11. RELATIONS……
 Anteriorly – Lateral
pterygoid
muscle,Masseteric nerves
and vessels.
 Posteriorly – Parotid gland
seperates it from external
acoustic meatus.
 Superiorly – Middle cranial
fossa
 Inferiorly – Maxillary artery
and vein,Middle meningeal
vessels

12. COMPONENTS OF TMJ
 TMJ is complex both morphologically and functionally.
 An articular disc composed of dense fibrous tissue is
interposed between temporal bone and mandible
dividing the articular space in to upper and lower
compartments.
 Gliding movements occurs in upper compartment and
hinge movements occurs in lower compartment.
 The articulating surface of TMJ are lined by dense
,avascular fibrous connective tissue.

13. COMPONENTS ….
 Articular surfaces of Temporal bone
 Mandibular condyle
 Articular disc
 Ligaments
 Muscular components

14. Articular surfaces
 Upper articular surfaces:
I)Articular tubercle
II) Anterior part of the
mandibular fossa
III) Posterior non-articular part
formed by tympanic plate

15. Articular surfaces
 Lower articular surfaces:
 I) Head of the mandible

16. Ligaments
 They are
I) Fibrous capsule
II) Lateral temporo-mandibular
ligament
III) Spheno-mandibular
ligament
IV) Stylo-mandibular ligament

17. Fibrous capsule
 Attachment:
Above: (From ant to post)
I) Articular tubercle
II) Mandibular fossa
III) Squamo tympanic fissure
Below:
Neck of the mandible

18. Temporomandibular ligament
 It is attached above to
the articular tubercle
 Below: posterolateral
aspect of neck of
mandible
 It primarily reinforces
and strengthens the
capsular ligament

19. Spheno-mandibular ligament
 An accessory ligament of
TMJ
 Above: spine of sphenoid
 Below: Lingula of
mandibular foramen
 It is the remnant of
Meckel’s cartilage

20. Stylo-mandibular ligament
 An another accessory ligament of
TMJ
 Attachment:
 Above: Styloid process
 Below: Posterior border of ramus of
mandible
 It represents the thickened part of
deep fascia that divides parotid and
submandibular regions.

21. Articular disc
 It is an oval plate of fibro-cartilage
which caps the head of mandible. It
divides the joint into two compartments
I) Menisco-temporal
II) Menisco-mandibular
 Morphologically it represents the
primitive insertion of lateral
pterygoid.
Attachment:
Ant: Blends with fibrous capsule
Post: It splits into two lamellae
I) Upper lamella: It is attached to the
squamo-tympanic fissure
II) Lower lamella: It is attached to posterior
surface of neck of mandible.

22. Functions of articular disc
 The upper surface is
concavo-convex which
provides a friction-free
gliding surface for the
condyle of mandible.
 Presence of articular disc
may also reduce wear
because the friction is nearly
halved.
 Alternate theory:
The articular disc forms
slippery surface with no
friction force dislocation
The position is largely
controlled by
neuromuscular forces

23. Blood supply & Innervation-
TMJ
 Blood supply:
Superficial temporal and maxillary arteries
The Blood supply to TMJ is majorly Superficial, i.e there is
no blood supply inside the capsule
TMJ takes its nourishment from Synovial fluid
 Nerve supply:
Masseteric and auriculotemporal nerves
 Hilton’s Law:
The principle that the nerve supplying a joint also supplies
both the muscles that move the joint and the skin
covering the articular insertion of those muscles
Auriculotemporal nerve
maxillary artery
Masseteric nerve
Superficial
temporal
artery

24. Movements of TMJ
 Rotational movement
occurs in first 20-25mm of
mouth opening
 Translational movement
after that when the mouth
is excessively opened

25. Movements…..
1. Depression Of Mandible
 Lateral pterygoid
 Digrastric
 Geniohyoid
2. Elevation of Mandible
 Temporalis
 Masseter
 Medial Pterygoids
3. Protrusion of Mandible
 Lateral Pterygoids
 Medial Pterygoids
4. Retraction of Mandible
 Posterior fibres of Temporalis

26. Age changes of the TMJ:
 Condyle:
 Becomes more flattened
 Fibrous capsule becomes thicker.
 Osteoporosis of underlying bone.
 Thinning or absence of cartilaginous zone.
 Disk:
 Becomes thinner.
 Shows hyalinization and chondroid changes.
 Synovial fold:
 Become fibrotic with thick basement membrane.
 Blood vessels and nerves:
 Walls of blood vessels thickened.
 Nerves decrease in number

27. These age changes lead
to:
 Decrease in the synovial fluid formation
 Impairment of motion due to decrease in the disc and
capsule extensibility
 Decrease the resilience during mastication due to
chondroid changes into collagenous elements
 Dysfunction in older people

28. CLINICAL EXAMINATION OF
TMJ
1. History taking
2. Measuring maximum interincisal opening
3. Palpation of pretragus area ; the lateral aspect of TMJ
4. Intra – auricular palpation ; the posterior aspect of TMJ
5. palpation of masseter muscle
6. Palpation of lateral pterygoid muscle
7. Palpation of medial pterygoid
8. Palpation of temporalis
9. Palpation of sternocliedomastoid
10. Palpation of digastric

29. SCREENING HISTORY AND
EXAMINATION
 Because the prevlance of TMD is very high , every
patient who comes to dental office should be screened
for these problems
 The purpose of screening history is to identify patients
with subclinical signs and symptoms that the patients
may not relate but are commonly associated with
functional disturbances of masticatory system
(headache , ear symptoms)
 The screening history consists of several questions
that will help orient the clinician to any TMD.

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

31. TMJ DISORDERS
 Temporomandibular joint disorders, or TMJ disorders,
are a group of medical problems related to the jaw
joint.
 TMJ disorders can cause headaches, ear pain, bite
problems, clicking sounds, locked jaws, and other
symptoms that can affect quality of life for the patient.

32. Classification of TMJ Disorders:
1. Developmental Disorders of TMJ
2. Degenerative Joint Disease
3. Inflammatory Disorders
of the Joint
4. Traumatic Disorders of TMJ
5. Metabolic Disorders
6. Neoplastic Disorders
7. TMJ Disorders Syndrome or Myofacial Pain Dysfunction Syndrome

33. Temporomandibular
joint dysfunction
 Temporomandibulasr joyint ndysfduncrtioon (smometeimes abbreviated to
TMD or TMJD and also termed temporomandibular joint
dysfunction syndrome, temporomandibular disorder or many other
names), is an umbrella term covering pain and dysfunction of the
muscles of mastication (the muscles that move the jaw) and the
temporomandibular joints (the joints which connect the About 20%
to 30% of the adult population are affected to some degree.
 Pain is constant, dull in nature, in contrast to the sudden sharp,
shooting, intermittent pain of neuralgias.
 The cause of MPD is controversial although it is generally
considered to be multifactorial
 Usually people affected by TMD are between 20 and 40 years of
age, and it is more common in females than males.
 TMD is the second most frequent cause of orofacial pain after
dental pain (i.e. toothache).

34. TMJD’S……
Cardinal symptoms of MPDS :-
1. Pain or discomfort anywhere about the head or neck.
2. Limitation of motion of the jaw.
3. Joint noises– grating,clicking,snapping.
4. Tenderness to palpation of the muscles of mastication.

35. TMJD’S…….
 Even though there are many treatments available,
there is a general lack of evidence for any treatment in
TMD, and no widely accepted treatment protocol
exists.
 Common treatments that are used include provision
of occlusal splints, psychosocial interventions like
cognitive behavioural therapy, and medications like
analgesics (pain killers) or others

36. TMJ DISLOCATION
 The mandible can dislocate in the anterior, posterior, lateral, or superior
position. Description of the dislocation is based on the location of the
condyle in comparison to the temporal articular groove.
 Anterior dislocations are the most common and result in displacement of the
condyle anterior to the articular eminence of the temporal bone. These
dislocations are classified as acute, chronic recurrent, or chronic
 TMJ dislocation may occur with trauma, but most often follows extreme
opening of the mouth during yawning, laughing, singing, vomiting, or dental
treatment .
 Dislocation also can result from dystonic reactions to drugs .
 Symmetric mandibular dislocation is most common, but unilateral dislocation
with the jaw deviating to the opposite side also can occur.
 TMJ dislocation is painful and frightening for the patient.

37. TMJ DISLOCATION….

38. TMJ ANKYLOSIS
 Ankylosis of the TMJ most
often results from trauma or
infection.
 True bilateral congenital
ankylosis of the TMJ leads
to micrognathia or “bird
face”.
 If ankylosis affects only
one side, it produces a
lateral deviation of the jaw
to the non-affected side,
due to the fact that this
side continues its growth
normally.

39. TMJ Radiographic views
 The various TMJ views are:
Transcranial view……. helps in the
visualization of the superior surface of the
condyle and the articular eminence.
Transorbital view………Zimmer projection or
transmaxillary projection. This view demonstrates
the entire lateromedial articulating surfaces of
both the condyle and the articular eminence and
the condylar neck.
Transpharyngeal view…………also called as
infracranial view, Parma projection, or McQueen
projection. This projection demonstrates the
condylar process from the midmandibular ramus
to the condyle. This technique helps in the
diagnosis of fractures of the condyle and the
condylar neck and in detecting alterations in the
condylar morphology.
TMJ tomography…………….. Tomography is a
technique used to demonstrate structures
located within a particular plane while blurring out
structures outside this plane, Tomography helps
in the visualization of the condyle, the articular
eminence, and the glenoid fossa. It can also be
used to determine the joint space.

40. LAB INVESTIGATIONS
No tests may be needed in straightforward cases.
Possible investigations are:
1.Blood tests: ESR, CRP for inflammation.
2.Plain radiographs - show gross bony pathology such as degeneration
or trauma.
3.CT or MRI scan of the joint. MRI scan shows the soft tissues and intra-articular
disc well.
4.Ultrasound - this is a useful alternative imaging technique for
monitoring TMJ disorders.
5.Diagnostic nerve block.
6.Arthroscopy.

41. TMJ SURGERIES
 Surgery may be indicated for some patients, mainly when conservative
treatments are not successful.
 It is usually supported by non-invasive treatment before and afterwards.
 Surgical options include:
1. Arthrocentesis
2. Therapeutic arthroscopy.
3.Removal of loose bone fragments.
4.Reshaping the condyle.
5.More complex procedures, including joint replacement,depending on the
pathology involved.

42. Temporomandibular joint surgery:
what does it mean to the dental
practitioner
 In March 2011, G Dimitroulis in vincents hospital
melbourne assesed why dental practioners should be
aware of benefits and risks of TMJ surgeries.
 They concluded that all dental practitioners should be
aware of the benefits of TMJ surgery so that patients
do not suffer unnecessarily from ongoing non-surgical
treatments that ultimately prove to be ineffective in the
management of their condition.

43. Temporomandibular joint problems and
periodontal condition in rheumatoid arthritis
patients
 In December 2011, Garib BT1 and Qaradaxi SS in College of
Dentistry, University of Sulaimani, Kurdistan assesed
Temporomandibular joint problems and periodontal condition in
rheumatoid arthritis patients in relation to their rheumatologic
status.
 They took plaque index, bleeding index, clinical attachment loss,
radiographic bone loss, tooth loss, and TMJ problems were
assessed in the 2 groups.
 They concluded that Patients with advanced RA are more likely
to develop more significant periodontal and TMJ problems
compared with patients with PD and without RA. There is a great
need to instruct patients with RA to consult a dentist to at least
decrease PD severity.

44. Periodontal Related TMJ
Disorders(journals)…….
 There are several areas where TMJ disorders may
impact which are , namely ……..dental caries,
periodontal disease, saliva abnormalities, oral health
and the effect of facial growth.
 The relationship of bruxism with TMD is debated.
Many suggest that sleep bruxism can be a causative
or contributory factor to pain symptoms in TMD.
 Indeed, the symptoms of TMD overlap with those of
bruxism. Others suggest that there is no strong
association between TMD and bruxism.

45. Christensen’s TMJ prosthesis(Implant)
REF: Christensen TMJ Fossa-Eminence Prosthesis System: a
retrospective clinical study.Britton C1, Christensen RW, Curry JT.
 A partial TMJ prosthesis consists of a meniscectomy
and placement of a metallic glenoid fossa metal
prosthesis (Christensen fossa prosthesis) in place of
the meniscus, such that a natural condyle articulates
with a metal fossa prosthesis. There is inadequate
evidence of the safety and effectiveness of partial joint
prostheses in the treatment of TMD.

46. CONCLUSION
 It is impossible to comprehend the fine points of occlusion without an in depth
awareness of anatomy ,physiology ,and biomechanics of the TMJ.
 The first requirement for successful occlusal treatment is stable, comfortable
TMJ.
 The jaw joints must be able to accept maximum loading by the elevator muscles
with no signs of discomfort.
 It is only through an understanding of how the normal, healthy TMJ functions that
we can make sense out of what is wrong when it isn't functioning comfortably.
 This understanding of TMJ is foundational to diagnosis and treatment.

47. References
1. Gray’s Anatomy
2. Fundamentals of occlusion and TMJ disorders
-- Okeson
3.B.D.Chaurasia
4. Grant’s Atlas of Human Anatomy
5. Occlusion – Ash RamfJord
6. Orthodontics Principles and Practice
-- T.M.Graber
7. Joseph H. Kronman et al (ajodo 1994;105:257-64.)
8. Stavros Kiliaridis et al ,European Journal of
Orthodontics 25 (2003) 259–263
9.Wikipedia