anatomical description with its applied anatomy

1. GUIDED BY- Dr. Bipin Bulgannawar
(H.O.D)
Dr. Khalid Agwani
Dr. Manish Sharma
Dr. Ramank Mathur
PRESENTED BY-
Dr. Raghvendra Singh Narela
P.G 2st year

2.  Introduction
 Classification of joints
 Articulation
 Components
 Condyle
 Glenoid fossa
 Articular eminence
 Capsule
 Articular disc
 Discal ligaments
 Extracapsular ligaments
 Synovial memrane

3.  Innervation and vascularization
 Biomechanics
 Applied surgical anatomy
 Disk disorders

4.  Joint of the jaw.
 There are two TMJ’s, one on
either side, working in unison.
 The name derived from the two
bones which form the joint:
 the upper temporal bone
which is part of the cranium
(skull)
 lower jaw bone called the
mandible.
Introduction

5.  The unique feature of the TMJs is the articular disc.
 The TMJs are one of the only synovial joints in the
human body with an articular disc, another being the
sternoclavicular joint..

6.  The most important functions of the temporomandibular joint (TMJ) are
mastication and speech and are of great interest to dentists and oral
surgeons.
 The TMJ is a ginglymoarthrodial joint.
 This term 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 common features of the synovial joints exhibited by this joint include :-
a) Disk
b) Bone
c) Fibrous capsule
d) Fluid
e) Synovial membrane
f) Ligaments
 However, the features that differentiate and make this joint unique are:

7.  Its articular surface covered by fibrocartilage
instead of hyaline cartilage.
 Bilateral diarthrosis – right & left function together.
 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.
 Develops from two distinct blastema

9.  Bilateral,
diarthoidal,
ginglymoid ,
synovial,freeely
movable joint.

“synovial sliding-
ginglymoid joint”
Articulation

10.  Diarthoidal – 2 articulating components
 i) condyle of the mandible –(1 )
 ii) squamous portion of the temporal bone–
concave articular fossa –(3)
 the convex articular eminence—(4)

11.  The 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.

12.  These two bones are actually separated by an
articular disc—(2), which divides the TMJ
into two distinct compartments

14.  Mandibular condyle (A1)
 The articular surface of
the temporal bone
i) glenoid fossa (A3)
ii) articular eminence
(A4)
 The fibrous capsule.(B1)
 The articular disc.(A2)
A
B
1

15.  Discal ligaments
 Extracapsular Ligaments
 Synovial membrane
 Mucsle (lat pterygoid)
A
B

17.  The condyle is elliptically shaped with its long axis
oriented mediolaterally
Condyle

18. It has lateral and medial
poles:
 The medial pole is
directed more posteriorly.
 Thus, if the long axes of
two condyles are
extended medially, they
meet at approximately
the basion on the anterior
limit of the foramen
magnum, forming an
angle that opens toward
the front ranging from
145° to 160°

19.  Broad mediolaterally (which
can avg between 17 and 23
mm)
 narrow ant post( 8 to 10 mm )
 Has –lat tubercle,
medial tubercle
joint capsule
Condyle

20.  Lat & med tubercle
provide attachments to
the lat & med collateral
lig.
Condyle

21. On medial aspect just below its
articular surface is a prominent
depression,
the pterygoid fovea, which is the site of
attachments of the lateral pterygoid
muscle
pterygoid fovea
Condyle

23.  Aka—Mandibular
fossa(MF)
 Limited post by
petrotympanic fissure(pf)
 Consists of lateral & medial
rims
 Lateral rim(lr)—continues
ant into zygomatic
tubercle(zt)
 Medial rim(mr)—just lat to
spine of sphenoid,foramen
spinosum,MM art.
MF mr
pf
lr
zt
Glenoid fossa

24.  Roof of fossa –thin &
separates brain from
the joint cavity
 Thus care should be
taken during surgical
manipulation
 Fossa is covered by
thin fibrous layer—
area not normally
loaded during
function
mid cranial fossa
Glenoid fossa

25.  The steep & more vertical form of the fossa has been associated
with :-
 1- articular disk displacement
 2- sublaxation
 3- dislocation
Glenoid fossa

27.  Consists of –
A descending
slope
Transverse ridge
Ascending ridge
 Covered by dense , compact
fibrous tissue— primarily
collagen with few elastic fibers
Articular eminence

28.  Underlying fibrous
layer—
 i)choncroid bone
ii)compact bone
 Sup strata of ant
bilaminar zone inserts
on the ascending
slopes—limits ant sup
recess
 Subjected to loading
during function
Articular eminence

30. The left temporomandibular joint viewed
from the sagittal aspect on a dry skull

31. The left temporomandibular joint viewed
from the
oblique/coronal aspect on a dry skull.

33.  Thin sleeve of tissue completely surrounding the
joint.
 Extends from the circumference of the cranial
articular surface to the neck of the mandible.
 The outline –
 anterolaterally to the articular tubercle,
 laterally to the lateral rim of the mandibular fossa,
 posterolateral to the postglenoid process,
 Importance-Enlargement of parotid gland (PG)could
impinge on the post capsule and cause pain
 posteriorly to the posterior articular ridge,
 medially to the medial margin of the temporal.

34. The outline of attachment on the
mandibular neck -
 Laterally- the lateral condylar
pole but
 Medially - dips below the medial
pole.
 On the lateral part of the joint,
the capsule is a well-defined
structure that functionally
limits the forward translation of
the condyle.

35.  Medially and laterally-
blends with the
condylodiscal ligaments.
• This capsule is reinforced more laterally by an
external TMJ ligament, which also limits the
distraction and the posterior movement of the
condyle.

36.  Anteriorly, the capsule has
an orifice through which
the lateral pterygoid
tendon passes. This area
of relative weakness in
the capsular lining
becomes a source of
possible herniation of
intra-articular tissues,
and this, in part, may
allow forward
displacement of the disk.

37.  The capsule is lined by
synovial membrane,
which lubricate the
joint.
Capsule

38. Functions:
 Seals joint space
 Passive stability
 does not restrain movements
 Synovial lining
 Proprioceptive nerve endings
Capsule

39.  Present betweeen the post capsule & post glenoid
tubercle
 Drawn into joint space during ant movements
 May be the cause of severe bleeding if lateral capsular
incision is extended into this area
VB

41.  Dense fibrous
plate (like the
firm and flexible
elastic cartilage
of the ear)
 Fills space bet
condyle &
temporol bone
Articular disc

42.  Very compressible
 Shallow contact area
 Free movement
Articular disc

43.  Aneural & Avascular
 Biconcave
 has med & lat rims
 Divide joint in 2 regions
Articular disc

44. • THE SUPERIOR SURFACE OF THE DISC - SADDLE-SHAPED
( TO FIT INTO THE CRANIAL CONTOUR )
• THE INFERIOR SURFACE - CONCAVE
( TO FIT AGAINST THE MANDIBULAR CONDYLE. )

45.  The inferior compartment
–
mandible condyle+
articular disc -rotational
movement (opening and
closing movements).
 The superior
Compartment–
articular disk + temporal
bone - translational
movements (sliding the
lower jaw forward or side to
side)
 Both joint spaces have small
capacities, generally 1cc or
less.
Articular disc

46. Articular disc

47. • Anatomical Disk
Structures =
• Central Thin Zone
• Anterior Band
• Posterior Band
• Posterior
Attachment
Articular disc

48.  The articular disc is a
roughly oval, firm, fibrous
plate.
1. anterior band = 2 mm in
thickness,
2. posterior band = 3 mm
thick,
3. thin in the centre
intermediate band of 1 mm
thickness.
More posteriorly there is a
bilaminar or retrodiscal
region.

49.  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.

50.  The anterior extension of
the disc is attached to a
fibrous capsule superiorly
and inferiorly.
 In between it gives
insertion to the lateral
pterygoid muscle where
the fibrous capsule is
lacking and the synovial
membrane is supported
only by loose areolar
tissue.

51.  The anterior and posterior
bands have predominantly
transversal running fibers,
while the thin
intermediate zone has
anteroposteriorly oriented
fibers.
 Primarily consists of
collagen(type I & II)
 High no. of fibroblasts ,
low chondroblast.
 Posteriorly, the bilaminar
region consists of two
layers of fibers separated
by loose connective tissue.

52.  The upper layer or
temporal lamina is
composed of elastin
and is attached to
the postglenoid
process, medially
extended ridge,
which is the true
posterior boundary
of the joint. It
prevents slipping of
the disc while
yawning.
• The inferior layer of the fibers or inferior lamina curve
down behind the condyle to fuse with the capsule and back
of the condylar neck at the lowest limit of the joint space. It
prevents excessive rotation of the disc over the condyle.

53.  In between the two
layers, an expansile, soft
pad of blood vessels and
nerves are sandwiched
and wrapped in elastic
fibers that aid in
contracting vessels and
retracting disc in recoil
of closing movements.
• The volume of retrodiscal tissue
must increase instantaneously
when the condyle translates
anteriorly.

54.  Provides stabilization during condylar
movement and shock absorption during
mastication.
 Glycoaminoglycans-distributed mainly in load
bearing areas
 -ve charge of GAGs absorbs water—helps in
restoring disc shape after stress are relieved
 Loss of GAGs – osteoarthiritis
Articular disc

55. Articular disc
figure

56. Articular disc

57. Articular disc

58. Articular disc
Perforation-commonly associated with degenerative
disease.

59. THANK YOU

61. 1. Discal
2. Extracapsular
 composed of collagen
 act predominantly as restraints to motion of the
condyle and the disk.
ligaments

62.  Vascular, innervated, fibroelastic
 Consists of--
i) Ant & post bilaminar ligaments
ii) Lat & med collateral ligaments
iii) Discomalleolar ligament

64.  Anterior ligament—
 Normally relaxed & fixed ( in centric
relation)
 Streches downward during mouth
opening
 Supported by superior & inferior head
of Left PGD muscle
 Consists of 2 stratas
i)Sup. Strata –
a) inserts on ascending slope of AE
b) limits the boundary of ant sup
recces
ii)Inf. Strata –
a) inserts at the ant aspect of
condyle
b)limits ant inf recess
Discal ligaments

65. Post ligament —
 Contains type I collagen& GAGs
 Has 2 stratas-
 i)Sup strata-
a) highly elastic
b) Inserts on lips of petrotympanic fissure
c) Limits the boundary of post sup recess
 ii)Inf. strata— a) also contains elastic fibers.
b) Inserts at the post angle of
condyle.
c) Limits post inferior recess.
 Stretches considerably during jaw movements.
 Allow the disk to continue to cover the condyle
at all range of movements.
Discal ligaments

66. During overloading—
 Pseudo disk formation-due to fibrotic change in post lig-may cause
degenerative dis
 Type II collagen, sulfated proteoglycans
 Obliterated blood vessels
 Nerve degeneration
Discal ligaments

67. Med & lat condylodiscal
( collaterall lig)—
 Collagenous,vascular ,
highly innervated
 Med lig receives nerve
fibers from LT PGD muscle
 Firmly attached to lat &
med poles of condyle(at
right angles)
 Could allow mediolat shift
of disk relative to condyle
during chewing
 Traumatic injury can lead
to-subluxation & med
displacement of disc
lcl mcl
Discal ligaments

68.  Discomalleolar / Pinto’s ligament—
 Post connection of med portion of disc
 Fibrous link between disc & the ant process of malleus of ear
Discal ligaments

70.  .
 define the border movements, or in other words, the farthest
extents of movements, of the mandible.
 movements of the mandible made past the extents functionally
allowed by the muscular attachments will result in painful stimuli,
 thus, movements past these more limited borders are rarely
achieved in normal function.
Extracapsular Ligaments

71. Main –
 1) temporomandibular lig
 2) sphenomandibular lig
Accessory—
1)Stylomandibular lig.
2)Pterygomandibular raphe
Extracapsular Ligaments

72. located on the lateral aspect of each
TMJ
 thickened lateral portion of the
capsule
 Fibers directed downwards &
backwards
 Attached- above--articular
tubercle,
below --lateral aspect of neck of
condyle
 Strengthens the lat part of
capsular lig
 has two parts: an outer oblique
portion (OOP) and an inner
horizontal portion (IHP).
TML

73. Outer oblique portion —
 Origin- outer aspect of
the articular tubercle of
the zygomatic process
 Insertion-- outer
posterior surface of the
condylar neck.
 limits the amount of
inferior distraction that
the condyle may achieve
in translatory and
rotational movements.

74. Inner horizantal portion—
 Origin-- outer surface of
the articular tubercle
 Insertion-- lateral pole of
the condyle and the
posterior aspect of the
disk
 limit posterior movement
of the condyle,
particularly during
pivoting movements, such
as when the mandible
moves laterally in
chewing function.
 This restriction protect
the retrodiskal tissue.

75. Remmenent of Meckel’s cart
 origin--- spine of the sphenoid
 Insertion--- i)mandibular
lingula
ii) the lower portion
of the medial side
of the condylar neck.
 serves -- point of rotation during
activation of the lateral
pterygoid muscle--contributing
to translation of the mandible
SpML

76.  Thickened part of deep cervical
fascia
 Origin-- the styloid process
 Insertion-- posterior border of
the angle of the mandible
 blends with the fascia of the
medial pterygoid muscle.
 It functions --
i)seperates parotid &
submandibular salivary gland
ii)as a point of rotation
iii) limits excessive protrusion
of the mandible.
StML

77. StML
SpML

79.  Lines the inside of TMJ
capsule & non-
articulating sufaces of
disk ligaments
 Synovial villous
projection can be seen as
hyperemic tissue
 Histologically 2 layers
 i) intima
 Ii) subimtima
Synovial membrane

80. Synovial membrane

81. i) intima—
 1-4 layers deep
 Consists of –
 Macrophage like cells-type A cells-
phagocytosis
 Fibroblast like cell-type B or S cells
secrete subintimal collagen &
proteoglycans & glycoproteins
Synovial membrane

82. ii) subintima–
 Vascular
 Consists of areolar loose connective tissue containing collagen &
elastic fibres or dense fibrous tissue
Synovial membrane

83.  The synovial fluid comes from two sources: first, from plasma by
dialysis, and second, by secretion from type A and B synoviocytes
with a volume of no more than 0.05 ml.
 However, contrast radiography studies have estimated that the
upper compartment could hold approximately 1.2 ml of fluid
without undue pressure being created, while the lower has a
capacity of approximately 0.5 ml.

84.  It is clear, straw-colored viscous fluid.
 It diffuses out from the rich cappillary network of the synovial
membrane.
Contains:
 Hyaluronic acid which is highly viscous
 May also contain some free cells mostly macrophages.
Functions:
 Lubricant for articulating surfaces.
 Carry nutrients to the avascular tissue of the joint.
 Clear the tissue debris caused by normal wear and tear of the
articulating surfaces.
 Increase in pressure—may cause osteoarthiritis-pain

87. Movements of synovial joint initiated & effected by muscle coordination.
Achieved in part through sensory innervation.
Hilton’s Law:
The principle that the nerve supplying a joint also supplies both the muscles that
move the joint and the skin covering the articular insertion of those muscles.
Therefore: Branches of the mandibular division of the fifth cranial
nerve supply the TMJ (auriculotemporal, deep temporal, and masseteric)

88.  Innervated structures-
 Joint capsule
 Disk ligaments(ant,post,med ,lat )
 Synovium

89.  Non-innervated structures-
 Disk proper
 Fibrous covering of articulating surfaces
 Condylar cartilage

90.  Innervation
The specific mechanics of proprioception in the
temporomandibular joint involve four receptors.
 1. Ruffini’s corpuscles
 2. Pacini’s corpuscles
 3. Golgi tendon organs
 4. Free nerve endings

91. 1.Ruffini endings
 (limited to capsule)
 static mechanoreceptors which position the
mandible.
2. Pacinian corpuscles
 (limited to capsule)
 dynamic mechanoreceptors which accelerate
movement during reflexes.

92. 3. Golgi tendon organs
 (confined to ligament)
 function as static mechanoreceptors for protection of ligaments
around the temporomandibular joint.
4.Free nerve endings (nociceptors)
(most abundant)
 are the pain receptors for protection of the temporomandibular
joint itself.

93.  The blood supply of T.M.J. is provided by branches of the external
carotid artery,
 predominately the superficial temporal branch.
 Other branches of the ECA namely:
 the maxillary artery-and
 deep auricular artery,
 anterior tympanic artery,
 ascending pharyngeal artery,
may also contribute to the arterial blood supply of the joint

94.  In order to work properly, there is neither innervation nor
vascularization within the central portion of the articular disc.
 Had there been any nerve fibers or blood vessels, people would
bleed whenever they moved their jaws; however, movement itself
would be too painful.

96.  Complex free movements of the mandible made possible by the
relation of four distinct joints involved in mandibular movement:
 the inferior and superior joints—bilaterally.
 Complex combinations of muscle activity
 Disk enables complex movements
Biomechanics

97.  During jaw movements, only the mandible moves.
 Normal movements of the mandible during function, such as
mastication, or chewing, are known as excursions.
 There are two lateral excursions (left and right) and the forward
excursion, known as protrusion.
 The reversal of protrusion is retrusion.
Biomechanics

98.  Two types of movement are possible:
 rotation and translation.
 rotation,a hinge-like motion--The inferior
joints--condyle and disk
 Translation– sup compartment

99. normal temporomandibular joint articulation in the closed and open positions.
first 20 mm
pure rotation
translatstranslates
Articulation

100.  All movements of the mand.( symmetric or asymmetric) -- close
contact of the condyle, disk, and articular eminence.
 Pure opening,( closing,protrusive, and retrusive ) -- bilaterally
symmetric action of the musculature.
 Asymmetric movements(chewing)-- unilateral movements of the
musculature with diff amounts of translation and rotation
occurring within the joints on either side.
Biomechanics

101.  In theory pure hinge motion of approximately 2.5 cm
measured at the incisal edges of the anterior teeth is
possible.
 The normal inter-incisal opening of mandible s in adult is
usually between 35 and 50 mm.
Biomechanics

102.  The maximum forward and lateral movement of the upper joint in
translation is approximately 1.5 cm.
Biomechanics

103.  The mandible is moved primary by the four
muscles of mastication: the masseter, medial
pterygoid, lateral pterygoid and the temporalis.
 These four muscles, all innervated by V3, or the
mandibular division of the trigeminal nerve,
work in different groups to move the mandible in
different directions.
Biomechanics

104.  - Retrusion, closure ipsilateral closure
contralateral

105. Lateral pterygoid (inferior head) --Protrusion,
opening contralateral
Lateral pterygoid (superior head)-- Retrusion,
closure, ipsilateral

109. Facial nerve emerging from stylomastoid foramen showing division into
upper trunk with temporal and zygomatic branches and lower trunk with
buccal, marginal, mandibular, and cervical branches
Facial Nerve

110. Fig 1.Surgical landmarks for
identifying location of main
trunk of the facial nerve and
the temporal-facial division
during joint arlhroplastic
dissection
Fig,2Note the variability at the point where the
upper trunk of the facial nerve crosses the
zygomatic trunk deep to the temporoparietal
fascia The nerve can cross point from 8 to 35
mm anterior lo the bony auditory canal.
Consequently, the plane of dissection must be
deep to the temporoparietal fascia as the
tissues are retracted anteriorly to gain access
to the joint capsule
Facial Nerve

111. the inferior extent of the incision is the soft tissue attachment of the lobule of the
ear and also the superior arm of the incision can be extended into the temporal
hairline at a 45-degree angle if greater anterior retraction of the surgical flap is
necessary.
Facial Nerve

112. Depiction of the auriculotemporal nerve emerging from the third division of
the trigeminal nerve coursing behind the neck of the condyle. The nerve
innervates the majority of the capsule and meniscal-attachment tissues. The
capsule is also innervated by the masseteric and posterior deep temporal
nerves.
trigeminal nerve

113.  VASCULAR ANATOMY
 The external carotid artery terminates in two branches: the
superficial temporal ,and
internal maxillary arteries.

114. Superficial temporal artery and vein, which run just below the subcutaneous
tissue anterior to the tragal cartilage.
The superficial temporal artery and vein are
routinely ligated during preauricular
approaches,

115. the internal maxillary (
usually just at or below the
level of the sigmoid
Notch )thus not
encountered unless
condylectomy is
performed.

116. Detailed view of the maxillary artery and its branches. The middle meningeal
artery courses medially from the maxillary artery, and the masseteric artery
runs laterally through the sigmoid notch. Both the maxillary and the
masseteric arteries can be damaged during extensive dissection.