Surgical Anatomy Of Temporomandibular Joint And Parotid Region

1. Surgical Anatomy Of
Temporomandibular Joint
And Parotid Region
MODERATED BY DR.GK THAPLIYAL BY-DR.NISHANT KUMAR

2. Surgical Anatomy Of
Temporomandibular
Joint

3. Introduction
 Craniomandibular Joint
 Ginglymoarthrodial Joint
 Ginglymoid : Hinge Joint
 Arthrodial : Gliding Motion
 Compound Joint

4. Peculiarity of TMJ
• Bilateral diarthrosis
• Articular surface covered by fibrous cartilage instead of hyaline cartilage
• It is the only bilateral joint that crosses the midline.
• Only joint in human body with rigid end point ,due to occlusion.

5. Articulatory system
A)Upper articularsurface:
• Articular tubercle
• Anterior part of the mandibular fossa
• Posterior non-articular part formed
by tympanic plate

6. B) Lower articularsurface:
• Head of mandible

7. Components
• ARTICULAR EMINENCE
• GLENOID FOSSA
• CONDYLE
• ARTICULAR DISC
• LIGAMENTS
• MUSCULAR COMPONENT

8. Articular eminence
•The anterior limit of the glenoid fossa
•Approximately 25° to the occlusal plane
•Forms most of the articular surface of the
mandibular fossa
•It extends out laterally to the zygomatic arch
as the articular tubercle

9. Glenoid Fossa
•Oval depression in temporal bone
•separates the joint from middle cranial fossa
•Bounded
• anteriorly -articular eminence
• laterally- zygomatic process,
• posteriorly - tympanic plate.
•Lined by: dense avascular fibrocartilage
•Cross section: fossa & eminence form ‘Lazy S’
PA

10. Clinical significance
 Chorda tympani nerve appears at the medial
end of petro tympanic fissure close to spine of
sphenoid.
 Roof of fossa is thin (separates brain from
joint) – avoid perforation of roof during
surgery of roof.
 Posteromedially: contents of the middle ear,
damaged by injudicious surgery

11. Condyle
•Ovoid structure
•The anteroposterior dimension of the condyle
(approximately 1 cm) being approximately half
the mediolateral dimension.
•It has a medial and lateral pole
•Long axis:15-330 to sagittal plane
•The articular surface area 200 mm 2

12. Capsule
A thin sleeve of tissue completely surrounding the joint.
Extends from the circumference of the cranial articular
surface to the neck of the mandible
• Attachments
• Inferiorly- neck of the condyle of the mandible.
• Superiorly-the mandibular fossa,
• Anteriorly - crest of the articular eminence,
• Posteriorly- the squamotympanic and petrotympanic
fissures,
• Medially- medial glenoid plane
• Laterally- between the lateral margin of
the articular eminence and the postglenoid process.

13. •Relations (medially)-
• Spine of sphenoid
• Sphenomandibular ligament
• Middle meningeal artery (through foramen
spinosum)
•Function:
• On the lateral part of the joint, capsule
functionally limits the forward translation
of the condyle.
• Medially and laterally- blends with the
discal ligaments

14. •Synovial membrane:
•Covers all intra-articular surfaces except the
pressure bearing fibro- cartilage.
•Releases synovial fluid
•Function
• Nutrition
• Lubrication

15. Articular disc
•Transversely oval disc
•Upper surface is concavo-convex from before
backward
•The lower surface is concave
Above, it covers the slope of the articular
eminence in front while below it covers the
condyle.
•Three distinct parts: an anterior band, a
thinner intermediate zone and a posterior
band .

16. •Anterior band (2mm)-
Narrow antero posteriorly
•Intermediate zone: 1mm (thinnest)
•Posterior band: 3mm –Thickest and widest
•More posteriorly: bilaminar or retrodiscal
region

17. ANTERIOR
CONFLUENT WITH CAPSULE, FASCIA
OF LATERAL PTERYGOID (SUPERIOR
HEAD
POSTERIOR
RETRODISCAL TISSUE

18. Articular space
•Upper compartment
• Gliding movement
• Upper compartment - 1.2ml
• Lower compartment
• Hinge/Rotation
• Gliding movement
• Lower compartment - 0.9 ml

19. Ligaments of temporomandibular joint

20. Temporomandibular (lateral) ligament
• Wide outer or superficial layer:
• Fan shaped.
• Origin: Outer surface of articular tubercle and
most of the posterior part of zygomatic arch.
• Fibres: run obliquely downward and
backward.
• Insertion: Behind and below the mandibular
neck.
• Narrow, inner or deep layer:
• Arises from the crest of articular tubercle.
• Runs back as flap strap to the lateral pole of
condyle.

21. Function:
•Limits protraction
•Inferior distraction
•Posterior movement of condyle
•Maintains integrity & limits movement of TMJ
(mainly anterior excursion & prevents
posterior dislocation – CHECK LIGAMENT
Slippage of condyle:
•Medially prevented by glenoid process
•Laterally by TM ligament

22. Collateral /discal ligament
 Attach medial & lateral borders of articular
disc to the poles of the condyle.
 True ligament (collagen i.e. don’t stretch)
Function:
• Restrict movement of disc away from
condyle (allow disc to move passively with
condyle as it glides anteriorly & posteriorly)

23. Accessory ligaments

24. Sphenomandibular ligament
Origin: Angular spine of sphenoid
Insertion: Lingula of the mandible
Relations:
– Laterally: Lateral pterygoid muscle
– Medially: Medial pterygoid muscle, chorda
tympani nerve.
– Anteriorly: Maxillary artery
– Posteriorly: Auriculotemporal nerve
– Inferiorly: Inferior alveolar nerve and
vessels.
Pierced by: Mylelohoid nerve and vessels

25. •Internal Maxillary artery between neck of
mandible and lateral pterygoid
•Auriculotemporal nerve lies between it & neck
of mandible.
•Chorda tympani branch of facial nerve crosses
the ligament at the upper end.
Clinical significance

26. Stylomandibular ligament
•Origin: apex and anterior aspect of stylohyoid
process and stylohyoid ligament.
•Insertion: angle and posterior border of
mandible
•Thickened band of deep cervical
fascia
•Function
• Limits extreme anterior movement of the
condyle in relation to the fossa

27. Muscular component
•Lateral movements:
• Medial & Lateral pterygoid
•Hinge movement:
• Geniohyoid
• Anterior belly of Digastric
•Translatory :
• lateral pterygoid
•Lateral pterygoid muscle attachments are of
surgical significance, since it is not possible to
remove the head of the condyle without
sectioning the insertion
•Where reattachment does not take place, some
joint function is lost and deviation of the jaw
occurs when opening widely.

28. Innervation and blood supply
•SENSORY INNERVATION:
•Auriculotemporal and Massetric branches of
Mandibular branch of Trigeminal nerve (V cranial
nerve).
•ARTERIAL BLOOD SUPPLY:
•Branches of external carotid artery, predominantly
the Superficial temporal branch.
•Other branches: Deep auricular artery, Anterior
tympanic artery, Ascending pharyngeal artery and
maxillary artery

29. Innervation and blood supply
•SENSORY INNERVATION:
•Auriculotemporal and Massetric branches of
Mandibular branch of Trigeminal nerve (V cranial
nerve).
•ARTERIAL BLOOD SUPPLY:
•Branches of external carotid artery, predominantly
the Superficial temporal branch.
•Other branches: Deep auricular artery, Anterior
tympanic artery, Ascending pharyngeal artery and
maxillary artery

30. Venous drainage
•Venous plexus around capsule
•Maxillary vein
•Transverse facial vein
•Superfacial temporal vein

31. Associated neurovascular structures
•Facial nerve:-
•Distance from the lowest point of the external
bony auditory canal to the bifurcation was
found to be 1.5–2.8cm (mean, 2.3cm), and the
distance from the postglenoid tubercle to the
bifurcation was 2.4–3.5cm (mean, 3.0cm) .
•The distance from the most anterior concavity
of the bony external auditory canal to the most
posterior significant temporal branch of the
facial nerve- 0.8-3.5 cm (mean 2 cm)

32. •Trigeminal nerve
•The auriculotemporal nerve courses from a
medial to a lateral direction behind the
neck of the condyle
•The inferior alveolar branch of the trigeminal
nerve enters the mandibular ramus on the
medial surface and runs inferiorly and
anteriorly until it exits through the mental
foramen.

33. •The external carotid artery
•The superficial temporal artery and vein are
routinely ligated during preauricular
approaches
•The internal maxillary artery normally
runs-approximately 3mm medial from the
midsigmoid notch.

34. •Most commonly injured artery
•The middle meningeal artery to be a
mean of 31mm (range 21–43mm) medial
to the zygomatic arch and a mean of
2.4mm (range -2 to 8mm) anterior from
the height of the glenoid fossa.

35. Surgical anatomy of
parotid region

36. • The parotid region includes the parotid
gland and duct, the facial nerve (CN VII),
the retromandibular vein, the external
carotid artery, and the masseter muscle.

37. Parotid Gland
Largest of the three paired major salivary
glands
Compound
Tubuloacinar
Merocrine
Exocrine gland
Composed entirely of serous acini

38. •Wedged between the posterior border of the
ramus of the and the mastoid process of the
temporal bone.
•Above -the external acoustic meatus, the
mandibular (glenoid) fossa housing the
condyle of the mandible, and the zygomatic
process of the temporal bone.
•Medially- the styloid process of the temporal
bone.
•. Below-the angle of the mandible

39. •Triangular in with the base lying above and the
apex being directed inferiorly .
• Average length of the gland is 6 cm while the
maximum width averages 3.3 cm .
•The accessory parotid gland usually lies above
the parotid duct.
• It is separated from the main parotid gland by
an average distance of 6 mm

40. Parotid capsule
•Continuation of the investing layer of deep
cervical fascia
•The superficial layer is attached above to the
zygomatic process of the temporal
bone, the cartilaginous part of the external
acoustic meatus, and the mastoid process
•The deep layer is attached to the
mandible, and the tympanic plate and the
styloid and mastoid processes of the temporal
bone

41. FORM AND RELATIONS OF THE PAROTID
GLAND
•Four borders (anterior, posterior, superior and inferior)
•Two surfaces (superficial and deep)
•The superior border -external acoustic meatus and
temporomandibular joint.
•The inferior border - angle of the mandible.
•The anterior border -posterior part of the masseter
muscle.
•
The posterior border -anterior border of the
sternocleidomastoid muscle.

42. •Site of the junction corresponds to a plane in
which lies the facial nerves and its branches,
as well as posterior facial vein.
•
•

43. •Superior border
• The superficial temporal vessels
• The auriculotemporal branch of the mandibular nerve
• The anterior border of the gland
• Branches of the facial nerve
• Parotid duct
• Transverse facial artery
•The inferior border
• Anterior and posterior branches of the posterior facial
(retromandibular) vein

44. CONTENTS OF THE PAROTID GLAND
•The facial nerve
•The auriculotemporal nerve
• The retromandibular vein
•The external carotid artery.

45. FACIAL NERVE
•The facial nerve exits the skull through the
stylomastoid foramen
•At the stylomastoid foramen, the facial nerve lies
about 9 mm from the posterior belly of the digastric
muscle and 11 mm from the bony external acoustic
meatus.
•The facial nerve then passes downwards and
forwards over the styloid process and the attached
muscles for an average distance of 1.3 cm before
entering the substance of the parotid gland.
•On entering the substance of the parotid gland, the
facial nerve soon separates into its two primary
components, the temporofacial and cervicofacial
divisions

46. •This division has various landmarks.
•It lies an average of 2.3 cm vertically
below the lowest point of the external
acoustic meatus, and an average of 3.2 cm
above the angle of the.

47. Temporal branch(es) of facial nerve
•The temporal branches usually number three
or four.
• They cross the zygomatic arch anteriorly to
the superficial temporal vessels at a region
intersected by a perpendicular from the
anterior temporal hairline.
•The nerve contributes to the supply of the
auricular muscles and supplies
muscles of the forehead and orbicularis oculi

48. Zygomatic branch(es) of the facial nerve
•The zygomatic branches may be up to three in
number and run below the lower border of the
zygomatic arch.
• They contribute to the innervation of the
orbicularis oculi, to muscles of the nose and to
muscles associated with the upper lip.

49. Buccal branch of the facial nerve
•A straight line drawn from the oral commissure
to the tragus approximately identifies the level
of the buccal branch (and the parotid duct).
•Where the nerve is single, it is usually (75%)
found below the origin of the parotid duct, but it
may cross the duct in 25% of cases in its anterior
course.
•Where there are two branches (15%), one branch
passes above and one below the
parotid duct.
•Beneath the zygomaticus muscle, the buccal
branch of the facial nerve supplies the buccinator
muscle and muscles of the upper lip

50. (Marginal) mandibular branch(es) of the
facial nerve
•The mandibular branch at the antero-inferior pole of the parotid
gland
• An important surgical relationship exists between the
mandibular branch and the lower border of the mandible.
•In one study, this nerve ran below the mandible in 20%
of cases, while another study reported a higher incidence of
53%, the furthest distance being 1.2 cm. Whereas the former
study reported that the mandibular branch of the facial nerve
was always above the lower border of the mandible distal to the
point where the facial artery crossed the mandible at the
anterior border of the masseter muscle, the latter study noted
that the nerve was still below the mandible in 6% of cases.
• The mandibular branch supplies the muscles of the lower lip
and, like the cervical branch below, lies in a plane deep to the
platysma muscle but superficial to the investing layer of deep
cervical fascia.

51. Cervical branch of facial nerve
•In 80% of cases, this appears as a single branch
•Always passes downwards at a variable distance
behind the angle of the mandible, the furthest
being 1.4 cm.
•The nerve passes behind the superficial portion of
the submandibular gland at the level of the hyoid
bone where it divides into a number of branches
which supply the platysma muscle.
• In the remaining 20% of cases, the nerve is
represented by two branches.

52. THE AURICULOTEMPORAL NERVE
•This nerve arises from the posterior division of
the mandibular division of the trigeminal nerve
in the infratemporal fossa.
•It enters the anteromedial surface of the parotid
gland,
passing upwards and outwards to emerge at the
superior border of the gland between the
temporomandibular joint and the
external acoustic meatus .
• the auriculotemporal nerve communicates with
the facial nerve.
•The communications with the temporofacial
division anchor the facial nerve close to the
lateral surface of the condylar process of the
mandible, limiting its mobility during

53. THE RETROMANDIBULAR VEIN
•The retromandibular vein is formed within the
parotid gland by the union of the superficial
temporal vein, that enters at the
superior border, and the maxillary vein, that
enters the posteromedial surface.
•The retromandibular vein passes downwards
and, near to the inferior pole of the parotid
gland, often divides into two branches which
pass out of the gland .
• the posterior branch passes backwards to unite
with the posterior auricular vein on the surface
of the sternocleidomastoid muscle
to form the external jugular vein.
•The anterior branch passes forwards to join the
facial vein .

54. •The retromandibular vein is an important landmark for
the facial nerve.
•The separation of the nerve into its two main divisions
(temporofacial and cervicofacial) occurs just posterior
to (within about 5 mm) the retromandibular vein. In
nearly 90% of cases, the two divisions of the facial
nerve are seen to lie superficial to the vein .
•Occasionally (9%), the temporofacial division is seen to
pass deep to the retromandibular vein, while only very
rarely (2%) does the cervicofacial division of the facial
nerve pass deep to the retromandibular vein.

55. THE EXTERNAL CAROTID ARTERY
•The deepest structure within the parotid gland is the external
carotid artery .
•This appears from behind the posterior belly of the digastric muscle
and grooves the posteromedial surface of the parotid gland before
entering it.
• The first branch given off by the external carotid artery within the
parotid compartment is the posterior auricular artery.
•Ascending to a position medial to the neck of the condylar process
of the mandible, the external carotid artery then divides into its two
terminal branches, the superficial temporal and maxillary arteries .
•The superficial temporal artery continues upwards to appear at the
superior border of the gland and crosses the zygomatic arch to the
temporal region.
•The maxillary artery emerges from the anteromedial surface of the
gland to enter the infratemporal fossa.

56. PAROTID DUCT
• This duct appears at the anterior border of the upper part of the
parotid gland .
• Passes horizontally across the masseter zmuscle, approximately at
the level midway between the angle of the mouth and the
zygomatic arch.
• If the duct arises lower down, it may run obliquely upwards.
• The duct lies below the transverse facial vessels and receives one
or more ducts from the accessory parotid gland when present.
• The parotid duct may also be crossed by anastomosing branches
between the zygomatic and buccal branches of the facial nerve.
• The duct bends sharply around the anterior border of the
masseter to pierce the buccal pad of fat and the buccinator muscle
at the level of the upper third molar tooth.
• A further bend in the duct is found as it passes forwards beneath
the oral mucosa before opening into the vestibule opposite the
crown of the upper second molar tooth.

57. THE INNERVATION OF THE PAROTID GLAND
•Sensory :
• Auriculotemporal nerve.
• Great auricular nerve.
•Autonomic:
• Sympathetic through plexus around the Arteries
(plexus around ECA)
• Parasympthetic through otic ganglion

58. •Knowledge of the secretomotor innervation to the
parotid gland has clinical significance in explaining
the redness and sweating that may develop in the
temple region following parotidectomy (frey’s
syndrome) when eating.
•The explanation forwarded to account for these
symptoms is that there is abnormal regeneration of
nerves such that secretomotor fibres, which
normally pass directly to the parotid gland,
regenerate beyond to the auriculotemporal nerve.
•Thus, the sweat glands and blood vessels in the skin
in the region of distribution of this nerve respond to
impulses that should reflexly stimulate parotid
secretion (gustatory sweating).

59. REFERENCES
SURGICAL ANATOMY OF INFRATEMPORAL FOSSA BY JOHN LANGDON
MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS BY J.OKESON
ATLAS OF TEMPOROMANDIBULAR SURGERIES BY PETER D QUEEN
GRAYS ANATOMY