ANATOMY TEMPOROMANDIBULAR JUNCTION OF HUMAN

Drg. Desi Fitriani, M. Kes
TEMPOROMANDIBULAR JOINT
(TMJ)

TEMPOROMANDIBULAR JOINT (TMJ)
 It is also referred to as the ginglymoarthrodial joint.
 It has both the ginglymus (a freely moving joint in
which the bones are so articulated as to allow
extensive movement in one plane) and the
arthroidia (a hollow area onto which the head of the
other bone joins).
 The temporomandibular joint (TMJ) is a type of
synovial joint.

 Sendi ini meliputi tulang mandibula dan tulang
temporal oleh sebab itu dikenal dengan sebutan
Temporo Mandibular Junction (TMJ). TMJ
menghubungkan madibula dengan tulang
tengkorak dan meregulasi pergerakan pada
mandibula sehingga berperan penting dalam
system pengunyahan dan bicara.

Three main types of joints: fibrous (immovable), cartilaginous
(partially movable) and synovial (freely movable) joints.
The following structures of TMJ:
1. Ligaments
Tough, white fibres that bind the bones together
2. Cartilage
Connective tissue that covers and cushions the bone ends
3. Articular capsule
Fibrous tissue that encloses the ends of the bones
4. Synovial membrane
Lines the capsule and secretes a lubricating fluid (synovia)

 The TMJ consists of the following hard-tissue and
soft-tissue components:
1. Bone/hard-tissue components
(a) Mandibular condyles
(b) Glenoid fossa of the temporal bone
(c) Articular eminence

2. Soft-tissue components
(a) Articular capsule
(b) Articular disc
(c) Ligaments
(d) Muscles

Mandibular Condyle
 covered by a thin, fibrous layer is called lamina
splendens which consists of poorly vascularized,
dense connective tissue with few fibroblasts and
chondrocytes. Type I collagen forms the major
component of this layer
 The condyle, in the earlier stages, has a layer of
proliferating hyaline cartilage underlying its
fibrous covering. The cartilage acts as an active
site of growth in the newborn and is later replaced
by bone.

 The fibrous layer consists of an outer layer of
dense collagen fibres arranged parallel to the
surface.
 Transitional layer composed of fibres arranged in
an oblique direction not as dense as the
superficial layer.
 Vertical layer, which is then followed by the
calcified cartilage layer overlying the cortical
bone.
 The thin layer of cortical bone is supported by the
trabeculae of spongy bone

 Superficial part of the intra-articular cortical bone
is nourished by the synovial fluid.
 The part of the condylar cortex and marrow
contained within the joint capsule is dependent on
the perforating blood vessels from the insertion of
the lateral pterygoid muscle for its blood supply.
 The extra-articular parts of the condylar head and
neck receive direct blood supply from the
periosteum and adjacent muscle tissues.

Glenoid Fossa of the Temporal Bone
 Situated on the inferior surface of the squamous part of
the temporal bone which articulates with the mandibular
condyle.
 Related anteriorly to the articular eminence, medially to
the spine of sphenoid, laterally to the root of the
zygomatic process of the temporal bone and posteriorly
to the squamotympanic and petrotympanic fissures. The
floor of the fossa is formed by a thin plate of bone.
 Covered by a fibrous layer similar to the condyle. It is thin
in the articular fossa and thickens in the posterior region
of the articular eminence.

Articular Eminence
 Binds the mandibular fossa anteriorly and forms
the anterior root of the zygomatic process.
 The articular eminence is convex
anteroposteriorly and concave in the transverse
direction. It is enclosed by the articular capsule of
the TMJ

Articular Capsule
 The articular capsule is a thin sleeve of dense,
cartilaginous tissue enclosing the joint cavity
 Attached to the margins of the glenoid fossa, the articular
eminence above and the neck of condyle below. The
anterolateral part is thickened to form the
temporomandibular ligament. Th posterior part blends
with the articular disc.
 The articular capsule consists of two layers:
1. An outer layer (stratum fibrosum) composed of
avascular, white fibrous tissue
2. An inner layer (stratum synoviale) which is a
secreting layer usually described separately as the
synovial membrane

Synovial Membrane
The synovial membrane is a thin and flexible layer lining the
inner surface of the joint capsule. The articulating surfaces and
the articulating disc are not covered by the membrane.
Consists of two layers:
1. Cellular intimal layer
Consists of one to two layers of synovial cells in an
amorphous intercellular matrix. The intimal layer is thrown into
villi-like folds.
There are two types of cells present in this layer:
(a) Macrophage for phagocytosis
(b) Fibroblast for repair and regeneration

2. Vascular subintimal layer:
 Resembling the endothelium, is embedded in an
amorphous matrix over a vascular bed. The
 Consists of loose connective tissue with blood
vessels, fibroblasts, macrophages and mast cells.
 The function of the synovial membrane is to
produce fluid which helps in lubricating the joint,
repairing the wear and draining the detritus (non-
living particulate organic material) accumulating
from normal function.

Articular Disc
 Is a roughly oval, firm, thick plate of dense, fibrous
cartilage,
 located between the condyle and the articulating surface
of the temporal bone.
 Divides the joint cavity into two compartments: superior
and inferior. Its viscoelasticity helps it to act as a shock
absorber and stress distributor.
 The disc provides a gliding motion during the opening
and closing of the jaw. It is thick at its periphery and thin
at the centre.
 The upper surface of the disc is concavoconvex to fit the
upper articular surface of the joint, and the lower surface
is concave for the head of the condyle to fit in.
 predominantly avascular; blood vessels are seen at the
margins of the disc.

 The articular disc is divided into four parts:
1. Anterior band
2. Intermediate band
3. Posterior band
4. Bilaminar zone
 The intermediate band consists of collagen fibres
running anteroposteriorly. It is thin when compared
with the anterior and posterior bands.
 The anterior and posterior bands consist of
fibreswhich run in the anteroposterior direction and in
the transverse or mediolateral direction.

 The superior surface of the disc is made up of fine
collagen fibres criss-crossing in a diagonal fashion. Below
this layer, strong collagen fibres run in an anteroposterior
direction; these fibres extend anteromedially to the upper
attachment of the lateral pterygoid muscle.
 The posterior margin consists of a thick band of coarse
fibres. The anterior margin also consists of transverse
bundles of coarse fibres.
 The disc is attached to the capsule posteriorly by a spongy
retrodiscal pad. The retrodiscal pad increases in volume
during opening movement of the joint because of pooling
of venous blood. As the joint closes, the blood flows out of
the retrodiscal pad.

 The retrodiscal pad is attached posteriorly to the
capsule by a bilaminar zone.
 This region has an upper and lower layer of
connective tissue fibres.
 The upper layer/lamina of the bilaminar zone
consists of elastic fibres whereas the lower
layer/lamina consists of inelastic fibres. This
unique shape of the disc permits the mechanical
movement of the condyle in a front and back
movement.

 Articular Ligaments
TMJ associated with four ligaments. One major
and three minor ligaments. The
temporomandibular ligament is the major
ligament. The sphenomandibular ligament,
stylomandibular ligament and
pterygomandibular raphe are the minor
ligaments.

Temporomandibular Ligament
 The temporomandibular ligament is a fan-shaped ligament present in
the lateral aspect of the articular capsule. It extends as a thickening
of the capsule obliquely in a backward and downward direction from
the lateral aspect of the articular eminence to the posterior part of the
condylar neck.
 The temporomandibular ligament consists of
two parts:
1. The outer part fibres are arranged obliquely and extend from
the outer surface of the articular eminence to the outer surface of the
condylar neck.
2. The inner part fibres are arranged horizontally and extend
from the outer surface of the articular eminence to the lateral surface
of the condyle.
 This ligament helps in preventing displacement in posterior and
inferior directions. Because the TMJ is a bilateral joint, the ligaments
help in preventing the lateral displacement of one joint and the
medial displacement of the other. Displacement of TMJ happens only
in the anterior or forward direction.

Sphenomandibular Ligament
 The sphenomandibular ligament is a flat, thin band which
is attached to the spine of the sphenoid above and to the
lingula of the mandible below. The function of this ligament
is to limit distension of the mandible in an inferior direction.
Stylomandibular Ligament
 The stylomandibular ligament is a specialized band, or the
free border, of the cervical fascia, which extends from the
apex of the styloid process of the temporal bone to the
posterior border of the angle of the mandible, between the
masseter and internal pterygoid.
 This ligament, along with the sphenomandibular ligament,
limits excessive opening of the mandible.

Pterygomandibular Raphe
 Is a tendinous band of the buccopharyngeal
fascia attached by one extremity to the hamulus
of the medial pterygoid plate and by the other
extremity to the posterior end of the mylohyoid
line of the mandible

 Otot-otot Rahang :
1. M. Pterigoideus Eksternus/lateral

2. M. Pterigoideus Internus/medial

MOVEMENTS OF THE JOINT
1. Hinge movements:
The opening or closing motions of the
mandible around a horizontal axis are known as
hinge movements. During the opening of the
mouth, the mandible moves down and the
condyle moves forward on the undersurface of
the disc, exhibiting a hinge movement. When
there is wider opening of the mouth, hinge
movement is followed by forward gliding of the
articular disc. The condyle moves backward
during the closing of the mouth

2. Translatory movements:
Protrusive or retrusive movements are called
translatory or sliding movements. As the mandible
moves during protrusion, both condyles leave their
fossae and move forward along the articular
eminences. When the mandible retrudes, both
condyles leave the eminences and move back into
their respective fossae. During the forward movement
or protrusion of the mandible, the condyle moves with
the articular discover the upper articular surface in a
forward direction. The opposite happens in retrusion
or reverse direction

3. Lateral movements
The side to which the mandible moves is called
the working side and the respective condyle is called
the working condyle. The side that is opposite to the
working side is called the balancing side and the
respective condyle is called the balancing condyle.
The movement at the joint happens in two zones:
between the upper articular surface and the articular
disc and between the disc and the head of the
mandible. The upper joint cavity allows gliding
movements and the lower joint cavity allows hinge
movements.

37
Gerakan TMJ  rotasi dan translasi
 Rotasi  di ruang sendi kaudal  kondilus
bergerak terhadap diskus sesuai dengan sumbu
yang berjalan melalui kepala kondilus

 Translasi  di ruang sendi kranial  kondilus
bergerak bersama diskus ke arah anterior mengikuti
lereng eminensia artikularis

38
Protrusi Mandibula
 Kedua kondilus bergerak ke depan melewati lereng
eminensia artikularis.
 M. Pterigoideus Eksternus dan Internus serta M.
Masseter dan serat anterior dari M. Temporalis
kontraksi. Serat posterior dari M. Temporalis
relaksasi.

39
Retrusi Mandibula
 Kedua kondilus bergerak ke arah belakang menuju
bagian posterior dari fossa mandibularis.
 Serat posterior dari M. Temporalis kontraksi, M.
Pterigoideus relaksasi.

40
Gerakan ke Lateral
 Saat dagu digerakkan ke satu sisi, kondilus pada sisi dimana
gerakan dituju  Mempertahankan posisi di fossa
mandibularis dgn tonus pada otot sisi tsbt.
 Pada sisi lain, kondilus bergerak ke depan  M. Pterigoideus
Eksternus kontraksi, serat posterior M. Temporalis relaksasi.
 Saat dagu dikembalikan posisinya ke midline  serat
posterior M. Temporalis kontraksi, M. Pterigoideus Eksternus
relaksasi.

KELAINAN DAN PENYAKIT TMJ
41
1. Perkembangan
a. Aplasia kondilus
 Kondilus mandibula tidak
berkembang dengan sempurna.
 Bisa unilateral atau bilateral.
 Kemungkinan etiologi : trauma saat
perkembangan atau infeksi radiasi.

42
b. Aplasia diskus artikularis
 Kelainan perkembangan  bentuk,
ukuran dan konsistensi dari diskus
artikularis tidak sempurna.
 Penyebab : kegagalan pembentukan
serat kolagen  yang merupakan
struktur dasar dari diskus.

2.Peradangan
43
a. Artritis traumatik
b. Infective artritis.
c. Artritis reumatoid
 E/ : diduga mekanisme otoimun.
 Sendi yang terkena  perad. synovial  jar
synovial hiperplasia
 Erosi perm. artikularis  resorpsi tulang.
 Permukaan sendi  tidak teratur, kasar 
ankilosis fibrosa.
 Bila meluas ke diskus artikularis  ankilosis
total.

3.Trismus
44
 Terbatasnya pergerakan TMJ yang bersifat temporer.
 Penyebab :
a. Infeksi & inflamasi pada sendi/ jar di
sekitarnya. Mis : perikoronitis akut &
mumps.
b. Trauma
c. Temporomandibular pain dysfunction
syndrome

4. Degenerasi
45
 Keadaan dimana terjadi perubahan patologik dari
persendian  gangguan fungsi sendi.
 Gejala klinis : rasa sakit pada pergerakan sendi, krepitasi,
keterbatasan gerak & penyimpangan pola gerakan sendi.

46
Gambaran Radiologis :
Penyempitan ruang artikularis
Melandainya kontur perm. sendi
Aposisi jaringan tulang
Pembentukan abN tepian tulang
Erosi perm. kondilus
Pembentukan tulang sklerotik di bawah
kartilago sendi

47
Faktor-faktor yang mempengaruhi terjadinya
degenerasi :
1. Faktor Biomekanik
 Perubahan oklusi, perubahan pola mastikasi,
kehilangan gigi posterior, kelainan bentuk
anatomi dan penggunaan protesa 
perubahan pola tekanan yang dialami TMJ.
 Bila besar tekanan melewati ambang batas
tahanan sendi & berlangsung lama 
degenerasi TMJ

48
2. Peradangan menahun
 Artritis dalam jangka waktu lama 
perubahan jaringan yang menetap 
perubahan struktur jaringan sendi
3. Gangguan nutrisi
 Berkurangnya nutrisi  perubahan
bahkan kematian jaringan.

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5. Dislokasi
E/ : pembukaan mulut yang terlalu
besar/akibat tindakan pencabutan gigi.
Keadaan ini harus segera diatasi, sebab bila
dibiarkan  terbentuk jaringan fibrosa yang
adhesif.
6. Neoplasma
Dapat mengenai kondilus atau jaringan
penyangganya

ANATOMY TEMPOROMANDIBULAR JUNCTION OF HUMAN

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