DEVELOPMENT, ANATOMY &
BY : JOEL D’SILVA
DEPARTMENT OF ORAL & MAXILLOIFACIAL SURGE
The most important functions of the
temporomandibular joint (TMJ) are
mastication and speech and are of great
interest to dentists, oral surgeons,
orthodontists, clinicians, and radiologists.
The TMJ is a ginglymoarthrodial joint, a
term that is derived from ginglymus,
meaning a hinge joint, allowing motion only
backward and forward in one plane, and
arthrodia, meaning a joint of which permits
a gliding motion of the surfaces.
The right and left TMJ form a bicondylar
articulation and ellipsoid variety of the
synovial joints similar to knee articulation.
The common features of the synovial joints
exhibited by this joint include
c) Fibrous capsule
e) Synovial membrane
However, the features that
differentiate and make this joint
Its articular surface covered by
fibrocartilage instead of hyaline
Bilateral diarthrosis – right & left
Articular surface covered by
fibrocartilage instead of hyaline
Only joint in human body to have a
rigid endpoint of closure that of the
teeth making occlusal contact.
In contrast to other diarthrodial joints
TMJ is last joint to start develop, in
about 7th week in utero.
Develops from two distinct blastema
Articular surfaces of Temporal bone
An ovoid process seated atop a
narrow mandibular neck. It’s
the articulating surface of the
It is convex in all directions but
wider latero-medially (15 to 20
mm) than antero-posteriorly (8
The medial pole is directed
Thus, if the long axes of
two condyles are extended
medially, they meet at
approximately the basion
on the anterior limit of the
foramen magnum, forming
an angle that opens toward
the front ranging from
145° to 160°
It has a medial and lateral pole
The lateral pole of the condyle
is rough, bluntly pointed, and
projects only moderately from
the plane of ramus, while the
medial pole extends sharply
inward from this plane.
The articular surface lies on its
anterosuperior aspect, thus
facing the posterior slope of the
articular eminence of the
The articular surface of the temporal
bone is situated on the inferior aspect
of temporal squama anterior to
• This is the entire transverse bony
bar that forms the anterior root
of zygoma. This articular surface
is most heavily traveled by the
condyle and disk as they ride
forward and backward in normal
• This is a small, raised, rough,
bony knob on the outer end of the
• It projects below the level of the
articular surface and serves to
attach the lateral collateral
ligament of the joint.
•This is the slightly
anteriorly from the height
of the articular eminence
The articular disc is the most
important anatomic structure of
It is a biconcave fibro
cartilaginous structure located
between the mandibular condyle
and the temporal bone
component of the joint.
Its functions to accommodate a
hinging action as well as the
gliding actions between the
temporal and mandibular
The articular disc is a roughly oval, firm, fibrous
1. anterior band = 2 mm in thickness,
2. posterior band = 3 mm thick,
3. thin in the center intermediate band of 1 mm
More posteriorly there is a bilaminar or
It is shaped like a peaked cap that
divides the joint into a larger upper
compartment and a smaller lower
Hinging movements take place in
the lower compartment and gliding
movements take place in the upper
The superior surface of the disc -
to fit into the
The inferior surface - concave
to fit against the
The disc is attached all around the joint capsule
except for the strong straps that fix the disc
directly to the medial and lateral condylar poles,
which ensure that the disc and condyle move
together in protraction and retraction.
The anterior extension of the disc is
attached to a fibrous capsule superiorly
In between it gives insertion to the
lateral pterygoid muscle where the
fibrous capsule is lacking and the
synovial membrane is supported only by
loose areolar tissue.
The anterior and posterior bands have
predominantly transversal running
fibers, while the thin intermediate zone
has anteroposteriorly oriented fibers.
Posteriorly, the bilaminar region
consists of two layers of fibers separated
by loose connective tissue.
The upper layer or temporal lamina is composed of
elastin and is attached to the postglenoid process,
medially extended ridge, which is the true posterior
boundary of the joint. It prevents slipping of the disc
The inferior layer of the fibers or inferior lamina
curve down behind the condyle to fuse with the
capsule and back of the condylar neck at the lowest
limit of the joint space. It prevents excessive rotation
of the disc over the condyle.
In between the two layers, an expansile, soft pad
of blood vessels and nerves are sandwiched and
wrapped in elastic fibers that aid in contracting
vessels and retracting disc in recoil of closing
The volume of retrodiscal tissue must increase
instantaneously when the condyle translates
Thin sleeve of tissue completely surrounding the
Extends from the circumference of the cranial
articular surface to the neck of the mandible.
anterolaterally to the articular tubercle,
laterally to the lateral rim of the
posterolaterally to the postglenoid process,
posteriorly to the posterior articular ridge,
medially to the medial margin of the
anteriorly it is attached to the preglenoid
MANDIBULAR NECK -
Laterally- the lateral condylar pole but
Medially - dips below the medial pole.
On the lateral part of the joint, the capsule is a
well-defined structure that functionally limits
the forward translation of the condyle.
This capsule is reinforced more laterally by an
external TMJ ligament, which also limits the
distraction and the posterior movement of the
Medially and laterally- blends with the
Anteriorly, the capsule has an
orifice through which the lateral
pterygoid tendon passes. This
area of relative weakness in the
capsular lining becomes a
source of possible herniation of
intra-articular tissues, and this,
in part, may allow forward
displacement of the disk.
The synovial membrane lining the capsule
covers all the intra-articular surfaces except
the pressure-bearing fibrocartilage.
There are four capsular or synovial sulci
situated at the posterior and anterior ends of
the upper and lower compartments.
These sulci change shape during translatory
movements, which requires the synovial
membrane to be flexible.
The ligament on each side of the jaw is
designed in two distinct layers.
The wide outer or superficial layer is usually
fan-shaped and arises from the outer surface
of the articular tubercle and most of the
posterior part of the zygomatic arch.
There is often a roughened, raised bony ridge
of attachment on this area.
The ligamentous fascicles run obliquely downward
and backward to be inserted on the back, behind,
and below the mandibular neck.
Immediately medial to this layer, a narrow
ligamentous band arises from the crest of the
articular tubercle continuously, with attachment of
the outer portion at this site.
This narrow inner or deep band runs horizontally
back as a flap strap to the lateral pole of the
An upper part of this band continues on to attach
to the back of the disk, lateral to the condylar pole.
Arises from the angular
spine of the sphenoid and
Runs downward and
Insert on the lingula of
1. Laterally - lateral pterygoidmuscle.
2. posteriorly - auriculotemporal nerve.
3. anteriorly - maxillary artery.
4. Inferiorly - the inferior alveolar nerve and
vessels a lobule of the parotid gland.
5. Medially - medial pterygoid with the
chorda tympani nerve and the wall of the
pharynx with fat and the pharyngeal veins
The ligament is pierced by
the myelohyoid nerve and
This ligament is passive
during jaw movements,
maintaining relatively the
same degree of tension
during both opening and
closing of the mouth.
This is a specialized dense, local
concentration of deep cervical fascia
extending from the apex and being adjacent
to the anterior aspect of the styloid process
and the stylohyoid ligament to the mandible’s
angle and posterior border.
This ligament then extends forward as a
broad fascial layer covering the inner
surface of the medial pterygoid muscle.
The anterior edge of the ligament is
thickened and sharply defined.
It is lax when the jaws are closed and
slackens noticeably when the mouth is
opened because the angle of the mandible
swings up and back while the condyle slides
downward and forward.
This ligament becomes tense only in extreme
protrusive movements. Thus, it can be
considered only as an accessory ligament of
The synovial fluid comes from two sources:
first, from plasma by dialysis, and second, by
secretion from type A and B synoviocytes
with a volume of not more than 0.05 ml.
However, contrast radiography studies have
estimated that the upper compartment could
hold approximately 1.2 ml of fluid without
undue pressure being created, while the
lower has a capacity of approximately 0.5 ml.
It is clear, straw-colored viscous fluid.
It diffuses out from the rich cappillary
network of the synovial membrane.
Hyaluronic acid which is highly viscous
May also contain some free cells mostly
Lubricant for articulating surfaces.
Carry nutrients to the avascular tissue of
Clear the tissue debris caused by normal
wear and tear of the articulating surfaces.
The way the teeth fit together may affect the
A stable occlusion with good tooth contact and
interdigitation provides maximum support to
the muscles and joint, while poor occlusion
(bite relationship) may cause the muscles to
malfunction and ultimately cause damage to
the joint itself.
Instability of the occlusion can increase the
pressure on the joint, causing damage and
A careful dissection of 16 intact human
cadaveric head specimens revealed The
location of the masseteric artery was then
determined in relation to 3 points process:
1) the anterior-superior aspect of the condylar
neck = 10.3 mm;
2) the most inferior aspect of the articular
tubercle = 11.4 mm;
3) the inferior aspect of the sigmoid notch = 3
Journal of Oral and Maxillofacial Surgery. 2009;67 (2) : 369–371
Rotational / hinge movement in first 20-
25mm of mouth opening
Translational movement after that when the
mouth is excessively opened.
Translatory movement – in the superior part
of the joint as the disc and the condyle
traverse anteriorly along the inclines of the
anterior tubercle to provide an anterior and
inferior movement of the mandible.
Hinge movement – the inferior portion of the
joint between the head of the condyle and
the lower surface of the disc to permit
opening of the mandible.
Protrusion of Mandible
Retraction of Mandible
Posterior fibres of Temporalis
Mainly 4 forms are
2. Flat- 25%
4. Round- 3%
( mainly in children)
A. Early development:
Develops relatively late compared to large
joints of extremities.
At 7th prenatal week jaw joint lacks condylar
growth cartilage joint cavities, synovial tissue
& articular capsule.
B. Condylar cartilage development
Between 8-12 wk of I.U life cartilagenous condyles
develop anteriorly to malleus incus articulation.
Then altered by endochondral bone formation &
fuses to posterior part of bony body of mandible.
By 12th wk condyle consists of large mass of
hyaline cartilage covered by a fibrous cap.
C . Articular disc formation;
In 12th wk first appearance of TMJ cavity is
seen & first of 2 compartments inferior or
mandibular compartment is formed.
A split appear in synovial mesenchyme &
temporal or superior compartment is formed
in next wk.
Presence of both sup & inf compartment
develops articular disc.
D . Fate of meckle’s cartilage;
As mandible enlarges remnants of meckles
cartilage becomes relatively smaller.
At 18-20 i.u life it loses its function &
Occurs in 14th I.U life .
Condyle grows by both interstitial &
appositional growth of condylar cartilage.
Formation of temporal fossa starts with
development of heavy spicule of temporal
bone superior to forming articular disc.
Articular disc takes its characteristic shape
& blends into articular capsule at 26th wk.
At 18-20 prenatal wk TMJ starts
The condylar bone increases in size &
density , & mandible undergoes changes in
shape & size associated with differentiation
& functioning of muscles of mastication.
Growth continues in 2nd decade of postnatal life
a. Temporal fossa deepens as bone forms
laterally & articular tubercle enlarges.
b. Dense fibrous nature of disc & capsule
c. condyles continue endochondral like growth .
Perichondral covering of condyle consists of 2
-portion lying next to cartilage which is highly
-outer layer which is fibrous.
Basic incision given by
Most basic & standard
approach to tmj.
Blair & Ivy (1936) –
“Inverted hockey stick “
Facilities exposure of
arch along with condylar
Thoma in 1958
-carried out across
zygomatic arch infront of
ear to avoid main trunk
of facial nerve.
Facial nerve divides in front of
auditory canal as near as 0.8cm
& as far as 3.5cm
Protection achieved by making
incision through temporal
fascia& periosteum down to
arch not more than 0.8cm.
Hoops et al (1970),
Alexander and James (1975)
Highly cosmetic incision
Disadvantage- poor access &
visibility,the risk of external
auditory meatus stenosis,
infection & deformity of the
Short facial skin incision
extending in to ext. auditory
Meatal stenosis or
chondritis, injury to the
branches of the facial nerve
Indication – surgeries of
condylar neck & ramus area.
Incision- 1cm behind ramus
of mand. and extends 1cm
below the lobe of ear.
Highly cosmetic, excellent
visibility and accessibility.
Injury may occur to posterior
facial vein and main trunk of
Mainly used for neck of
condyle & ramus region.
supplement to different
tmj approaches for
tunneling through the soft
tissues to place a graft
Hemicoronal (unilateral) or bicoronal (bilateral)
approach is used.
More extensive but versatile approach for upper
& middle regions of facial skeleton, zygomatic
arch & TMJ.
Advantage- scar is hidden in the hairline.
GREY`S ANATOMY (38TH EDITION)
SICHER & DUBRUL`S ORAL ANATOMY (8TH
ANATOMY OF HEAD & NECK BY B.D CHAURSIA
TEXTOOK OF ORAL & MAXILLOFACIAL SURGERY
BY NEELIMA MALIK.
TEXTBOOK OF TMJ DISORDERS BY EDWARD F.
TEXTBOOK OF TMJ DISORDERS BY KAPLAN &