Detailed discussion on surgical anatomy of TMJ and its applied aspects. Surgical approaches are also discussed.

1. Surgical Anatomy of
Temporomandibular Joint

2. Introduction
• Anatomy of the temporomandi-
bular joint (TMJ) is highly specific
and correlates with jaw function
• 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 most important functions of
the TMJ include mastication and
speech

3. Bony
Components
Components of TMJ
Soft-tissue
components
• Condyle of
mandible
• Articular eminence
• Glenoid fossa
• Articular disc
• Joint capsule
• Ligaments
• Muscles

4. Unique features of TMJ
•Its articular surface covered by fibrocartilage
instead of hyaline cartilage.
•The right and left TMJ form a bicondylar articulation
and functions together as one unit.
•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.

5. The Mandibular Condyle
• Head of the condyle is oval in
shape mediolaterally
• 15-20mm long (M-L); 8-10mm
wide (A-P); 8-120mm thick
• Medial pole > Lateral pole
• Posterior surface > Anterior
surface
• Articular surface is covered by
fibrocartilage

6. Condylar Forms
(According to Gray’s anatomy)
Mainly 4 forms are
seen
1. Convex-58%
2. Flat- 25%
3. Pointed-12%
4. Round- 3% ( mainly
in children)

7. Cranial component of TMJ
• Comprises of the articular suface of
the temporal bone
• Articular eminence:
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 jaw function
• Articular tubercle
1. small, raised, rough, bony knob
on the outer end of the articular
eminence.
2. serves to attach the lateral
collateral ligament of the joint.
• Preglenoid plane
Articular surface continuing
anteriorly from the height of the
articular eminence

9. Articular Disc
• Biconcave, avascular fibro
cartilaginous structure located
between the mandibular condyle and
glenoid fossa
• functions to accommodate a hinging
action as well as the gliding actions
between the temporal and
mandibular articular bone
• Hinging movements take place in the
lower compartment and gliding
movements take place in the upper
compartment.
• 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.

10. • Superior surface- Saddle-shaped
• Inferior surface- Concave
• Anteriorly – Attached to superior
belly of lateral pterygoid
• Posteriorly - Bilaminar region
consists of two layers of fibers
separated by loose connective
tissue which is vascular.
• Parts:
1. anterior band = 2 mm in
thickness
2. posterior band = 3 mm thick,
3. Thin in the center intermediate
band of 1 mm thickness.
4. posteriorly there is a bilaminar
or retrodiscal region.

11. Ligaments related to TMJ
Functions
1. Restricts and limits joint
movements
2. Maintain joint spaces
True ligaments:
1. Capsular ligament
2. Lateral/
Temporomandibular
ligament
Accessory ligaments:
1. Stylomandibular
ligament
2. Sphenomandibular
ligament

12. • Blood supply:
Branches of External Carotid Artery:
Mainly branches of superficial temporal artery
Venous supply:
1. Maxillary vein
2. Tranverse facial vein
3. Superficial temporal vein.
• Blood supply to TMJ is only superficial
• TMJ takes its nourishment from Synovial fluid
• Nerve supply of TMJ:
1. Auriculotemporal nerve
2. Masseteric nerve
3. Posterior deep temporal nerve

13. Factors maintaining stability of TMJ
• Bones – Forward displacement
prevented by articular tubercle and
backward displacement is
prevented by postglenoid tubercles
• Temporomandibular Ligament
• Protusion – Prevented by temporalis
• Retrusion – Prevented by lat
pterygoid
• Occlusal intercuspation
• Anterior dislocation is most
common

14. Relations of TMJ
• Anteriorly
1. Mandibular notch
2. Lateral pterygoid
3. Masseteric nerve and artery

15. Relations of TMJ
Posteriorly
1. Parotid gland
2. Superficial temporal
vessels
3. Auriculotemporal nerve

16. Relations of TMJ
• Laterally –
1. Skin, superficial fascia, SMAS
layer
2. Temporal branches of VII nerve
3. Parotid gland

17. Relations of TMJ
• Medially –
1. Tympanic plate (separates from ICA) spine of sphenoid
2. Auriculotemporal nerve & Chorda tympani nerve
3. Middle meningeal artery &Internal maxillary artery

19. Important structures related to TMJ
 Nerves:
1. Facial nerve
2. Auriculotemporal nerve
3. Inferior alveolar nerve
 Vascular structures:
• Middle meningeal artery
• Internal maxillary artery
• Superficial temporal artery
• Masseteric artery

20. Facial Nerve
• The main trunk of the facial nerve exits from the
skull at the stylomastoid foramen.
• Surgical landmarks for identification of
facial nerve:
• Tragal pointer - The main trunk of the facial nerve
is located 1 cm anteroinferior and 1 cm deep to
the tip of the tragal cartilage.
• Digastric ridge- The main trunk is just superior to
the attachment of the posterior belly of the
digastric muscle to the digastric groove. This
landmark also marks the approximate depth of the
facial nerve.
• Stylomastoid foramen - The base of the styloid
process is 5 to 8 mm deep to the tympanomastoid
suture line. The facial nerve can be identified as it
exits the stylomastoid foramen and passes over
the posterolateral aspect of the styloid process.
• Tympanomastoid suture line - The nerve lies 6 to
8 mm deep to the inferior end of the
tympanomastoid suture line.
• Mastoid - For revision cases, extensive tumors or,
as a last resort, a mastoidectomy can be
performed to locate the vertical segment of the
facial nerve, which can then be followed as it exits
the mastoid.

21. Relation of VII nerve with TMJ
• Approximately 1.3 cm of the facial nerve is visible to surgeon
until it divides into temporofacial and cervicofacial branches
• According to Alkayat & Bramley’s classic article (1979)

22. Radiologic study by Miloro et al

23. Applied Aspects
• The temporal branch of the facial
nerve emerges from the parotid gland
and crosses the zygoma under the
temporoparietal fascial to innervate
the frontalis muscle (“corrugator
muscle”)
• Postsurgical palsy manifests as an
inability to raise the eyebrow
and ptosis of the brow.
• Damage to the zygomatic branch
results in temporary or permanent
paralysis to the orbicularis oculi and
may require temporary patching of the
eye to prevent corneal desiccation and
abrasion.

24. Auriculotemporal Nerve
• first branch of the mandibular nerve after it
exits the foramen ovale.
• supplies sensation to the skin in the temporal
and preauricular region, the anterior external
meatus
• The auriculotemporal nerve provides most of
the innervation to the capsule of the
temporomandibular joint itself
• Branch of mandibular nerve, post division
• Radiographic assessment of the exact course
of this nerve through the mandible is
necessary if screws will be placed through the
ramus as is necessary for prosthetic joint
replacement
Inferior Alveolar Nerve

25. Vascular anatomy of TMJ
• Superficial temporal artery and vein:
are routinely ligated during preauricular
approaches.
• Internal maxillary artery: is usually not
encountered unless a condylectomy is
performed.
If a condylectomy is performed,
Dunn‐Dautrey retractors are used as
the internal maxillary artery normally
runs-approximately 3 mm medial from the
midsigmoid notch.

26. Talebzadeh N, Rosenstein TP, Pogrel MA. Anatomy of the structures medial
to the temporomandibular joint. Oral Surgery, Oral Medicine, Oral
Pathology, Oral Radiology and Endodontics. 1999 Dec 1;88(6):674-8.

27. Masseteric artery
A careful dissection of 16 intact
human cadaveric head specimens was
done. 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 mm.
Journal of Oral and Maxillofacial
Surgery. 2009;67 (2) : 369–371

28. Surgical Approaches to TMJ
1. Preauricular : Dingman’s, Blair’s, Thoma’s,
Al-kayat and Bramley’s, Popowitch’s
2. Postauricular
3. Endaural approach
4. Post ramal/ Hind’s approach
5. Submandibular/Risdon’s approach
6. Hemicoronal
7. Bicoronal

29. Preauricular Approach
• Basic incision was given by
Dingman (1951)
• Blair & Ivy modification–
“Inverted hockey stick “
incision. Facilitate exposure
of arch along with condylar
area.
• Thoma in 1958 Angulated
vertical incision. -carried out
across zygomatic arch infront
of ear to avoid zygomatic
branch of facial nerve

30. Alkayat and Bramley Modified Preauricular Incision
1. Reduced haemorrhage 2. Provision of donor site for temporalis fascia
3. Better cosmetic result 4.Lesser chance of facial nerve injury

31. Facial nerve branches are not damaged

32. Post auricular approach
• Introduced by Bockenheimer
• Advantage:
1. Excellent exposure of the
entire joint and the ability
to camouflage the scar
in patients who have a
tendency to form keloids.
2. Better posterior exposure
of TMJ
• Disadvantage:
1. Auricular stenosis
2. Should not be used in the
presence of joint infection
or chronic otitis externa

33. Post-auricular approach

34. Endaural Approach
• Lempart (1938)
• Short facial skin incision
extending in to ext. auditory
meatus
• Advantage: Excellent cosmetics
and posterolateral exposure
• Disadvantage:
1. Meatal stenosis or
chondritis
2. Injury to the branches of the
facial nerve
• Care must be taken not to incise
the tragal cartilage because a
perichondritis or poor wound
healing may result.

35. Post-ramal/ Hind’s Approach
• E.C Hinds & Girotin (1967)
• Indications –
1. Condylar neck fractures
2. Condylotomy
3. Vertical ramus osteotomy
• Incision- 1cm behind ramus of
mand. and extends 1cm below the
lobe of ear.
• Advantages: Highly cosmetic,
excellent visibility and accessibility.
• Note: Injury may occur to posterior
facial vein and main trunk of facial
nerve.

36. Structures encountered during Hind’s approach

37. Combination of Retromandibular + Endaural Approach
• Indication:
For additional access to the
temporomandibular joint for open
fracture reduction, costochondral
grafting, total alloplastic joint
reconstruction, or tumor
resection.
• When combining both incisions,
the surgeon must leave an
intervening bridge of tissue that
extends inferiorly at least 3 cm
from the lowest point of the
bony external auditory canal to
protect VII nerve

38. Submandibular Risdon’s Approach
•Risdon (1934)
•Mainly used for
neck of condyle &
ramus region
•Incision: Placed
one‐finger breadth
below the angle of
the mandible
ensuring avoidance
of the marginal
mandibular nerve

40. Dingman RO, Grabb WC. Surgical anatomy of the mandibular ramus of the
facial nerve based on the dissection of 100 facial halves. Plastic and
Reconstructive Surgery. 1962 Mar 1;29(3):266-72.
• The marginal mandi-
bular(MMN) branch of the facial
nerve, posterior to the facial
artery, passed above the inferior
border of the mandible in 81%
of dissections
• It ran superficial to the facial
vein in 98% cases
• Damage to MMN:
The patient is unable to depress
the lower lip and show the
mandibular anterior teeth.

41. Intraoral Approach
• Incision along the external
oblique ridge. A subperiosteal
dissection proceeds medially and
laterally along the mandibular
ramus
• The coronoid process and
condylar neck can be reached
through this incision.
• Advantages:
Decreased facial and
auriculotemporal nerve injury and
improved scar placement.
• Limitations:
limited access to the structures
superior to the condylar neck.

42. Conclusion
• The incisions which are chosen to approach the TMJ are
established in accordance with requirements of regional
anatomy and function.
• Ideally, the selected approach should accomplish the
following:
1. maximize exposure for the specific procedure;
2. avoid damage to the branches of the facial nerve, major
vessels (e.g., internal maxillary artery and retromandibular
vein), parotid gland, and ear;
3. maximize use of natural skin creases for cosmetic wound
closure.
• .

43. References
• Atlas of Temporomandibular Joint Surgery (2nd edition) – Peter Quinn
• Al‐Kayat A, Bramley P. (1980) A modified preauricular approach to
the temporomandibular joint and malar arch. Br J Oral Surg, 17:91.
• Dingman RO, Grabb WC. (1962) Surgical anatomy of the mandibular
ramus of the facial nerve, based on the dissection of 100 facial
halves. Plast Reconstr Sur, 29:266.
• Talebzadeh N. et al. (1999) Anatomy of the structures medial to the
temporomandibular joint. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod, 88:674.
• Kreutziger KL. Surgery of the temporomandibular joint. I. Surgical
anatomy and surgical incisions. Oral Surgery, Oral Medicine, Oral
Pathology and Oral Radiology. 1984 Dec 1;58(6):637-46.
• Textbook of Human Anatomy by A.K. Dutta