The temporomandibular joint (TMJ) connects the mandible to the temporal bone. It is a diarthrodial joint that allows for both hinge and gliding movements. The TMJ consists of the condylar process of the mandible, the mandibular fossa of the temporal bone, articular discs, synovial fluid, ligaments including the temporomandibular, sphenomandibular and stylomandibular ligaments, and muscles like the masseter, temporalis, and lateral and medial pterygoid muscles. The muscles of mastication work together to elevate, retract, protrude and move the mandible from side to side for

2. Temporo-Mandibular Joint /
Craniomandibular Articulation
> Receives its name from
the 2 cranial bones
which enter into its
formation,
1. temporal bone
2. mandible.
> It is closely associated
with the role of teeth in
the oral cavity.

3.  Classification:
Diarthrosis Joint (Freely movable joint)
- one in which a fibrous capsule
connects the 2 bones. A space is
provided between the 2 bones which is
lined by synovial membrane, thus
allowing free movement of the joint.

4.  Variety:
Ginglymoarthrodial
- allows both hinge and gliding
movements.
 Consists of:
a) Bone d) Synovial
b) Ligament membrane
c) Cartilage e) Muscles

5. A. Articulating Bony Parts:
1. Mandibular Fossa of
the Temporal Bone/
Glenoid Fossa
- an oval depression
in the temporal bone just
anterior to the auditory
canal

6. 2. Condyloid Process/
Condylar Process/
Mandibular Condyle
- a knob-like bone
(wider latero-medially
than antero-posteriorly), it
is convex on all bearing
surfaces although
somewhat flattened
posteriorly.

7. 3. Articulating Tubercle/
Articular Eminence
- bony elevation
located anterior and
posterior to the glenoid
fossa or mandibular
fossa.

8. Anterior Articular Eminence
- anterior to the mandibular fossa
- controls the forward movement of
the condylar head
Posterior Articular Eminence
- posterior to the mandibular fossa
- controls the backward movement of
the condylar head

9. B. Ligaments:
1. Capsular
Ligament
- a synovial
capsule which
completely
surrounds the
condyle.

10. - Divided into 4 portions:
a) Anterior portion
b) Posterior Portion
c) Internal Portion
d) External Portion /
Temporomandibular Ligament

11. Temporomandibular
Ligament
- largest portion
- acts as main
suspensory ligament
of the mandible during
moderate opening
movement (hinge).

12. - it has a broad attachment above
the zygomatic process of the
temporal bone, the anterior fibers
attaching forward beyond the
articular eminence & is inserted into
the outer side and posterior margin of
the neck of the condyle.

13. 2. Sphenomandibular
Ligament
- round & cordlike at
its origin and takes
more of a ribbon like
form at its insertion.

14. - with wider opening of the jaw,
the condyle move forward rapidly,
relaxing the external lateral
ligament as the
sphenomandibular ligament
becomes tensed or slightly
stretched.

15. - originates from the spinous
process of the sphenoid bone and
inserts into the lingula of the
mandible with some fibers attached
below the mandibular foramen.

16. 3. Stylomandibular
Ligament
- extends from the
styloid process of the
temporal bone and
inserts into the posterior
border of the ramus of
the mandible.

17. - just before the stylomandibular
ligament makes its insertion, it gives
off an accessory fiber which continue
downward to the posterior border of
the hyoid bone, called the stylohyoid
ligament.

18.  * the temporomandibular ligament
& the sphenomandibular ligament
acts as suspensory ligaments.
 * the stylomandibular ligament & its
accessory stylohyoid ligament acts
as checkrein on the mandible and
helps prevent excessive anterior drift
at the angle during more extreme
opening movements.

19. C. Cartilage
Meniscus – a tough
fibrous disc also
known as
Interarticular Disc or
Interarticular
Fibrocartilage.

20. Cavities:
a) Menisco-Temporal Cavity
- larger cavity
- allows gliding of the
condylar head to the
articular eminence.
b) Menisco-Condylar Cavity
- smaller cavity
- allows hinge
movement of the
condylar head.

21. D. Synovial Membrane
- lines the internal surface of the
meniscus.
- Synovial Fluid lubricates the
articulating parts.

22. E. Muscles
Muscles of Mastication
1) Masseter
2) Temporalis
3) Internal or Medial Pterygoid
4) External or Lateral Pterygoid

23.  Masseter
- is a flat,
quadrangular
muscle, partly
tendinous, partly
fleshy.

24. Origin:
Superior portion – anterior 2/3 of the
lower zygomatic arch.
Deeper portion – whole length of deep
surface of the zygomatic arch.

25. Insertion: on the lateral surface of the
coronoid process, ramus & gonion.
Action: is to elevate the jaw with the
superficial fibers causing protraction.

26.  Temporalis
- is a large, fan-
shaped muscle on
the side of the
head.

27. Origin: floor of the temporal fossa &
temporal fascia.
Insertion: apex & deep surface of the
coronoid process and along the
anterior border of the ramus down to
the last lower molar tooth.

28. Action:
Anterior fibers – elevate the mandible
Posterior fibers – retract the mandible

29.  * anterior part acts as synergist with
the masseter in clenching.
 * posterior part may acts as
antagonist to the masseter in
retruding the jaw.

30.  Internal or Medial
Pterygoid
- is quadrilateral in
shape.

31. Origin: from the medial surface of the
lateral pterygoid plate, the posterior
surface of the tubercle of the palatine
bone and the tuberosity of the
maxilla.

32. Insertion: is into the triangular
impression on the medial surface of
the mandible between its mylohyoid
groove and the angle.

33. Action: is to elevate & protract the
mandible. It also moves the jaw from
side to side when acting singly.

34.  External or Lateral
Pterygoid
- is a thick and
triangular muscle
with two heads.

35. Origin:
Superior portion – is from the
infratemporal surface of the great
wing of the sphenoid.
Inferior portion – is from the lateral
surface of the lateral pterygoid
plate.

36. Insertion: the fibers are directed
laterally and backwards into the front
of the neck of the mandible & into the
capsule of the TMJ.

37. Action: is to depress, protrude & move
the mandible from side to side.