ANATOMY OF TMJ

1. Lecture By:
Dr. Chitransha
TEMPOROMANDIBULAR
JOINT

2.  On each side of the head, between
temporal bone and mandible, that
allows the movements of the
mandible for speech and
mastication.

3.  It is described as a complex, biaxial,
synovial & bicondylar joint.
 Also known as the craniomandibular
joint or bilateral diarthroidial joint.

4. ARTICULAR SURFACES
The upper articular surface is formed
by:
1. Articular fossa (anterior part of
Mandibular Fossa )and
2. Articular tubercle of the temporal
bone.
 This surface is concavo-convex from
behind forwards.

6.  The inferior articular surface is
formed by:
1. Head (condyle) of the mandible.
 This surface is elliptical in shape.
The articular surfaces are covered
by fibrocartilage and not by hyaline
cartilage, hence TMJ is an atypical
synovial joint.

8. Gross Anatomy of TMJ
 BONY
COMPONENTS
Condylar Head
Articular Fossa
Articular
tubercle
 SOFT TISSUE
COMPONENTS
Articular Disc
Synovial fluid
Ligaments

11.  The cavity of TMJ is divided by an
intra-articular disc of fibrocartilage
(MENISCUS) into
upper menisco-temporal
lower menisco-mandibular
compartments.

12. Articular Disc
 The articular disc is an oval plate of
fibrocartilage.
 The periphery of the disc is attached
firmly to the fibrous capsule.

13.  The ligaments are
1. Fibrous Capsule
2. Temporomandibular
3. Sphenomandibular
4. Stylomandibular Ligaments

14. Fibrous capsule
 It is a fibrous sac to enclose the joint
cavity.
 It is attached above to the articular
tubercle, the circumference of
articular fossa, and the
squamotympanic fissure and below to
the neck of mandible.
 The synovial membrane lines the
inner aspect of the fibrous capsule

16. Lateral (temporomandibular)
ligament
 It is a true ligament and formed as a
result of thickening on the lateral
aspect of the capsular ligament.
 It is attached above to the articular
tubercle and below to the
posterolateral aspect of the neck of
the mandible.
 The lateral ligament strengthens the
lateral aspect of the capsule.

18. Sphenomandibular ligament
 It is attached above to the spine of
the sphenoid and below to the lingula
of the mandible.
 The sphenomandibular ligament
represents the unossified
intermediate part of the sheath of the
Meckel’s cartilage of the first
pharyngeal arch.
 It becomes accentuated and taut
when the mandible is protruded.

19. Stylomandibular ligament
 It is attached above to the lateral
surface of the styloid process and
below to the angle of the mandible.
 The stylomandibular ligament is
formed due to thickening of the
investing layer of deep cervical fascia,
which separates the parotid and
submandibular glands.
 This ligament also becomes taut
when the mandible is protruded.

21. Relations of TMJ

22. Lateral
 Skin and fasciae.
 Parotid gland.
 Temporal branches of the facial
nerve.

23. Medial
 Tympanic plate separating it from
internal carotid artery.
 Spine of sphenoid.
 Auriculotemporal nerve.
 Middle meningeal artery.
 Sphenomandibular ligament.
 Chorda tympani nerve.

25. Anterior
 Lateral pterygoid.
 Masseteric nerve and vessels.

26. Posterior
 Postglenoid part of parotid gland
separating it from external auditory
meatus.
 Superficial temporal vessels.
 Auriculotemporal nerve

27. NERVE SUPPLY
 Auriculotemporal nerve
 Masseteric nerve

28. BLOOD SUPPLY
 Maxillary artery.
 Superficial temporal artery.
Veins follow the arteries.

29. LYMPHATIC DRAINAGE
 The lymph from TMJ is drained into:
 Superficial parotid (preauricular)
nodes.
 Deep parotid nodes.
 Upper deep cervical nodes.

30.  The movements occurring at the
temporomandibular joints are:
1) Depression
2) Elevation
3) Protraction
4) Retraction
5) Side to side (Chewing)
movements

31. Muscles Producing
Movement
 Depression (Opening of Mouth)
It is produced mainly by lateral
Pterygoid helped by gravity.
The digastric, geniohyoid, and
mylohyoid muscles help when the
mouth is opened widely or against
resistance.

32.  Elevation (Closing the Mouth)
It is caused by medial pterygoid,
masseter, and temporalis (vertical
fibres).

33.  Protraction
 Lateral and medial pterygoids and
superficial fibres of masseter.

34.  Retraction
It is done by posterior fibres of
temporalis.
Assisted by middle and deep fibres
of the masseter, the digastric and
geniohyoid muscles.

35.  Side-to-side (Chewing) Movements:
 These movements are performed
by alternate contraction of medial
and lateral pterygoids on each side.

36. APPLIED
 Dislocation of mandible
 Ankylosis
 During surgery of
temporomandibular joints, the facial
nerve should be preserved.