The TMJ is a complex and precisely integrated bilateral joint structure .  Formed by the articulation of lower jaw with cranium and the upper facial skeleton This presentaion was submitted in Dept.of Oral pathology in Goverment Dental College Raipur.

1. TEMPOROMANDIBULAR JOINT
Submitted By Dr.Vibhuti Amin
Internee Government Dental College ,Raipur[C.G]
Guided By Dr Sonali Ma’am
HOD-Oral Pathology
Government Dental College, Raipur[C.G]

2. INTRODUCTION
The TMJ is a complex and precisely integrated bilateral
joint structure .
Formed by the articulation of lower jaw with cranium
and the upper facial skeleton .
BONES TAKING PART ARE –MANDIBULAR
+TEMPORAL BONES = TEMPOROMANDIBULAR
JOINT .
The head of the condyle of the mandible articulates with
the articular fossa and articular eminence of the
temporal bone .
It functions in speech ,mastication and deglutition .
The downward and forward sliding action of the
condylar heads can be felt while:
opening and closing the mouth and during symmetric protrusion and retrusion
and asymmetric lateral shift .

3. MANDIBLE
ANATOMY
 The TMJ is a synovial bilateral joint that permits the mandible to move as a unit
with 2 functional patterns (gliding and hinge movements)
 The TMJ is a ginglymoarthrodial joint, a termthat is derived from ginglymus,
meaning a hinge joint, allowing motion only backward andforward in one plane,
and arthrodia, meaning a joint of which permits a gliding motion of the
surfaces..
 The common features of the synovial jointsexhibited by this joint include a disk,
bone,fibrous capsule, fluid, synovial membrane,and ligaments.However the
features that differentiate and make this joint unique are its articular surface
covered by fibrocartilage instead of hyalinecartilage.
PECULIARITY OF TMJ

4. 1. Bilateral diarthrosis– right & left function
together
2. Articular surface covered by fibrocartilage
instead of hyaline cartilage
3. Only joint in human body to have a rigid
end point of closure governed by the teeth making
occlusal contact.
COMPONENTS
(Bone/Hard components )
Mandibular condyle
Glenoid fossa of the temporal bone
Articular eminence
(Soft tissue components )
Capsule
Articular disc
Ligaments
Muscular component
The mandibular condyle articulates with the glenoid fossa and articular eminence of the
temporal bone.
An articular disc
separates the articular
surfaces so that 2
cavities are present:
Upper compartment between the
disc and temporal bone.
Lower compartment between the
condyle and the disc
The joint capsule is
attached below to the
articular margin of the
head of the condyle,
and above to the
margins of the
glenoid fossa and

5. articular eminence.
The inner aspect of
the capsule is lined
by a synovial
membrane.
At the sides, the capsule is strengthened by collateral ligaments of which the lateral
temporomandibular ligament is the strongest.
The lateral temporo-mandibular ligament is attached above to the
zygoma, and below, it is attached to the lateral surfaces and posterior border of the
neck of the mandible.
There are 2 accessory ligaments associated with the TMJ:
The stylomandibular ligament attaches to the styloid process
and to the posterior border of the ramus.
The sphenomandibular ligament extends between the spine of the sphenoid bone
and the lingula of the mandible.
These ligaments limit the range of movement of the condyle preventing it from
coming in contact with the tympanic plate behind and passing beyond the articular
eminence in front.
THE MANDIBULAR CONDYLE
It’s the articulating surface of the mandible.
It is convex in all directions but wider
latero-medially than antero-posteriorly.
It has lateral and medial poles:

6. The medial pole is directed more posteriorly.
The long axis of the two poles deviate
posteriorly and meets at the anterior
border of the foramen magnum.
HISTOLOGY
Composed of cancellous bone covered by a thin layer of compact bone.
Trabeculae: of the cancellous bone is arranged in a radiating manner from the neck
to reach the surface of the condyle at a right angle (to give maximum strength.)
Bone marrow is of myeloid or cellular type and becomes fatty with age.
Outer layer of compact bone is covered by thick layers of fibrous tissues
composed of:
Superficial layer : network of strong collagen fibers, chondrocytes
and fibroblasts.
Deep layer: thin collagen fibers rich in chondroid cells during growth
period (hyaline cartilage).
Growth occur by apposition from the deepest layer – the deepest
surface of the cartilaginous plate is replaced by bone.
Growth continues till 21 years of age
Remnants of cartilage may persist in old age.
MANDIBULAR (GLENOID) FOSSA
AND
ARTICULAR EMINENCE
Glenoid fossa:
Posteriorly limited by the
squamotympanic fissure.
Anterioly bounded by the
articular eminence.
Roof: thin layer of compact
bone separating the middle

7. cranial fossa.
Articular eminence:
Composed of: Spongy bone covered by thin layer of compact bone.
Chondroid tissues commonly seen in the eminence.
Fibrous layer covering the articulating surface of temporal bone.
Thin on the articular fossa and thickens on the posterior slope of the eminence
Over the eminence the fibrous tissues are arranged in 3 zones:
Inner zone – fibers arranged at right angle to surface
Outer zone – fibers run parallel to the bone surface
Intermediate zone – transitional zone.
Fibers are interlaced.
INTERARTICULAR DISC (MENISCUS )
Disk is fibrous, avascular, non inverted plate
Shape is oval, biconcave in sagittal section. It is thin in central part and
thick at posterior borders
Attachment: Medial and lateral
poles of the condyle by medial
and lateral ligaments.
Divide the joint into: Upper
(larger) compartment and
lower (smaller) compartment
Anterior border divides into upper
and lower lamellae that run forward.
The upper lamella fuses with the
anterior slope of the articular
eminence.
The lower lamella attaches to the
front of the neck of the condyle.
Fibers of the superior head of the
lateral pterygoid muscle is attached

8. to the anterior border.
Posterior Border divides into upper and lower lamellae
 The upper lamella is fibrous and elastic and fuses with the capsule and is
inserted in the squamotympanic fissure.
 The lower lamella,non elastic,attaches to the back of the condyle..
HISTOLOGY
Composed of dense fibrous tissue containing:
Straight and tightly packed collagenous fibers
Few elastic fibers.
Some chondroid cells appear with age.
Chondrocytes may be seen. The space between upper and lower posterior is filled
with highly vascular loose connective tissue
vascular loose connective tissue
ARTICULATING CAPSULE AND
LIGAMENTS AND
SYNOVIAL MEMBRANE
The whole TMJ is enclosed in a fibrous
capsule.
It is attached to:
Articular tubercle (in front)
Lips of squamous tympanic fissure
(posteriorly)
Borders of articulating glenoid fossa
Neck of the mandible. (below)
It is lined by synovial membrane.
Laterally, the capsule is reinforced by TMJ
ligaments.
HISTOLOGY
Consists of 2 layers:
Outer fibrous capsule – strengthen laterally to form the
temporomandibular ligament.

9. Inner synovial layer – composed of thin connective tissue layer lined
with:
Synovial cells
Type A : secretes hyaluronic acid
Type B : produces protein rich secretion.
Synovial folds and villi protrude from the surface into the joint
cavity.
Synovial layer of cells line the entire capsule of both upper and
lower joint spaces.
Synovial membrane is very rich in blood supply and contains
lymphatic vessels.
SYNOVIAL FLUID
It is clear, straw-colored viscous fluid.
It diffuses out from the rich cappillary network of the synovial membrane.
Contains:
Hyaluronic acid which is highly viscous
May also contain some free cells mostly macrophages.
Functions:
Lubricant for articulating surfaces.
Carry nutrients to the avascular tissue of the joint.
Clear the tissue debris caused by normal wear and tear of the articulating surfaces
BLOOD SUPPLY
4 arteries supply the joint:
Superficial temporal
Deep auricular
Anterior tympanic
Ascending pharyngeal
Branches from the 4 approach the joint and penetrate the capsule
NERVE SUPPLY
Branches from the mandibular nerve
Auriculotemporal nerve
Masseteric nerve
Deep temporal nerves

10. Supply all surfaces of the head, fossa, capsule and part of the disk
DEVELOPMENT OF TMJ
Ontogenetically & Phylogenitically TMJ is a secondary joint. i.e it is developed from
primary reptilian type .in reptilian type ,the TMJ is formed at dorsal end of meckel’s
cartilage ,which in humans appear as joint between malleus and incus bones of
the middle year showing adaptation of bones of primitive jaw to sound conduction.
Meckel’s cartilage forms and provide skeletal support for developing lower jaw .
Cartilage extends backward and dorsally and terminates as malleus
7th week - Articulation between malleus and incus at the dorsal end of Meckel’s
cartilage – PRIMARY JOINT .
• 8th week- Membranous Bone laid down in a plate like form lateral to Meckels
cartilage.
• 10 week (IU) -from 2 widely separated centers that grow toward each other
evidence of future joint as mesenchyme between the condylar cartilage & developing
temporal bone.(temporal and condylar blastema )
12 week:
A pair of clefts appears in the mesenchyme between developing squamous
portion of temporal bone
And develops into upper and lower joint cavity
Joint capsule is formed from condensation of mesenchyme (which progressively
isolates the joint with its linning synovial membrane )
Condylar grows dorsolaterally
Ossification of temporal blastema
Inferior joint cavity
Differentiation of condylar into cartilage & Sup.joint cavity
Formation of disc
13th week : Condyle and
articular disk have moved up
into contact with temporal
bone. • Remnant of meckels
cartilage sphenomandibular ligament
• Full differentiation of all
articular surfaces occurs by4th fetal month
MUSCLES

11. Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
Elevation of Mandible
Temporalis
Masseter
Medial Pterygoids
Depression Of Mandible
Lateral pterygoid
Digastric
Geniohyoid
Protrusion of Mandible
Lateral Pterygoids
Medial Pterygoids
Retraction of Mandible
Posterior fibres of Temporalis
Actions of the muscle of mastication
A.Elevation –M Masseter ;MPt,medial pterygoid ; T.Temporalis
B.Depression –IH.Infra hyoid ;LPt,lateral petrygoid ;SH,suprahyoid
C.Protrusion .M (Sup),masseter,superficial fibers .
D.Retrusion .M(deep ) masseter ,deep fibers ; T(horizontal) Temporalis ,horizontal
fibers .
E.Right lateral excrusion of the mandible Lt.Mpt,left medial pterygoid ,Lt Pt,left
lateral pterygoid ,Rt M ,right masseter ,Rt T ,Right Temporalis
F.Left lateral excrusion of the mandible . Lt M ,LEFT masseter .Lt T ,Left
temporalis ,Rt Lpt ,right lateral pterygoid ,Rt MPt ,right medial pterygoid
MOVEMENTS OF TMJ
Rotational movement
occur
s in first 20-25mm
of mouth opening
Translational

12. movement after that
when the mouth is
excessively opened
CHANGINGPOSITION OF THE MANDIBLE
AGE CHANGES
Condyle:
Becomes more flattened
Fibrous capsule becomes thicker.
Osteoporosis of underlying bone.
Thinning or absence of cartilaginous zone.

13. 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
CHANGES COULD LEAD TO:
Dysfunction in old age
Impairment of motion due to decrease in the extensibility of the disk and
the capsule.
Decrease in the secretion of the synovial fluid.
The term myofacial pain dysfucntion syndrome (MPDS) is used to
indicate a dysfunction of TMJ
Characterized by
Masticatory muscle tenderness (mostly lateral pterygoid ,temporalis
,medial pterygoid and masseter .)
Limited opening of the mandible <37 mm .
Joint sounds .
Dislocation of the TMJ may take place without impact of external force
. It is usually bilateral and displacement is anterior .
When mouth is opened wide during yawning ,head of the mandible slip
forward into the infra temporal fossa causing articular dislocation of
the joint .
Recent diagnostic techniques such as CT (COMPUTERIZED TOMOGRAPHY ) and
MRI (MAGNETIC RESONANCE IMAGING) permit the visualization of the TMJ disk
inpatients
The disk ,for reasons not yet determined ,becomes displaced anteromedially and
creates one or more of the following signs and symptoms :pain ,clicking ,limitation
of jaw movement ,deviation or opening or locking .
If remains untreated it leads to osteoarthrosis

14. T
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