Week 2: TMJ Flashcards
The TMJ is an articulation of the:
mandibular condyle and mandibular fossa or the temporal bone
Osteology of the TMJ:
mandibular condyle
mandibular fossa
articular eminence of the temporal bone
TMJ is a ____________ joint.
synovial or modified hinge
The articular eminence and the mandibular condyle are both convex, which results in:
an incongruent joint
The TMJ articulation is covered with ____________, not hyaline cartilage.
fibrocartilage
The incongruence of the TMJ joint is addressed by:
the articular disc.
The articular disc of the TMJ joint is:
biconcave
what is the purpose of the articular disc?
it allows CONVEX surfaces to remain congruent through ROM it increases stability it minimizes loss of mobility it reduces friction it decreases biomechanical stress on TMJ
The disc separates into the inferior TMJ and superior TMJ. The inferior TMJ is a simple _________ joint and the superior TMJ is a ___________ joint.
hinge; gliding
The upper joint of the TMJ is an articulation between:
The articular eminence with superior disc
The lower joint is an articulation of:
the condyle and inferior disc
The disc is attached to the:
medial and lateral poles of the condyle
The attachment of the articular disc to the medial and lateral poles of the condyle allow for the condyles to:
rotate freely on the disc in a AP direction
The disc is also attached to the:
joint capsule and lateral pterygoid anteriorly
The attachment of the articular disc to the joint capsule and lateral pterygoid anteriorly restricts:
posterior translation of the disc
The articular disc is also attached to the _____________ retrodiscal pad posteriorly
bilaminar
The superior lamina helps the disc in:
translating anteriorly with mandibular depression
The inferior lamina:
limits forward translation
Available joint motion of the TMJ is determined by:
elasticity of the joint capsule and ligaments
Describe the capsule of the TMJ joint.
it is thin and loose anteriorly and posterior
it allows for anterior translation when mouth is open
TMJ is PREDISPOSED to anterior dislocation of the mandibular condyle due to lack of strength of the anterior capsule and the incongruence of the articular surfaces.
what are the 3 ligaments in the TMJ?
Lateral Ligament
stylomandibular ligament
sphenomandibular ligament
Which ligament has a primary function to stabilize lateral portion of the capsule and helps guide movement of condyle during opening?
Lateral ligament
Which is the weakest of the 3 ligaments with questionable function?
stylomandibular ligament
Which ligament is a swinging hinge that suspends the mandible?
sphenomandibular ligament
TMJ resting position
lips closed
teeth several millimeters apart
TMJ resting position is maintained by:
low level activity of the temporalis muscle
The TMJ joint allows for which movements?
depression/elevation
protrusion/ retrusion
left and right lateral excursion
There are two phases associated with depression and elevation:
early phase and late phase
Depression in the early phase causes a __________ posterior in the lower joint.
roll
depression in the late phase causes a ___________ anteriorly of the upper joint.
glide
Elevation also has two phases:
early and late phase
In the early phase of elevation, there is a ____________ posteriorly of the upper joint.
glide
in the late phase of elevation, there is an ____________ roll of the lower joint.
roll
protrusion occurs by:
an anterior and slightly inferior glide of the condyle and disc
retrusion occurs by:
a posterior and slightly superior glide of condyle and disc
No ____________ or ____________ occurs with protrusion and retrusion.
rotation or rolling
Lateral excursion is a side to side _____________ of the condyle and disc within the fossa.
translation
The ipsilateral condyle is a relatively fixed pivot point during _________ excursion.
lateral
Left lateral excursion:
right condyle glides anteriorly and to the left
left condyle spins
right lateral excursion
left condyle glides anterior and to the right.
right condyle spin
Depression is caused by:
gravity
digastrics
suprahyoid
lateral pterygoid
Elevation of TMJ is caused by:
temporalis
masseter
medial pterygoid
control of disc via superior lateral pterygoid
Protrusion is able to occur due to these muscles:
B masseters
B medial pterygoids
B lateral pterygoids
Retrusion of the TMJ occurs due to:
B temporalis
B masseter
B digastric (assist)
lateral deviation can happen thanks to:
contralateral med/lateral pterygoid
ipsilateral temporalis
ipsilateral masseter
What is formed around the angle of the mandible by the masseter and medial pterygoid?
a functional sling
Contraction of what two muscles produces a powerful bite?
masseter and medial pterygoid
interaction between what two muscles are also very effective at grinding and crushing food?
masseter and medial pterygoid.
explain the process of the interaction of the masseter and medial pterygoid between grinding and crushing food.
The R medial pterygoid and the L masseter produce L lateral deviation which creates shear force between molars and foods.
Normal depression of TMJ:
35 - 50 mm
mastication requires _____ mm of _______________.
18; depression
functional screen of mandibular depression:
2 knuckles: functional
3 knuckles: normal
normal protrusion of TMJ =
3 - 6 mm
Normal retrusion of TMJ is:
3 - 4 mm
normal lateral deviation of TMJ =
10 - 15 mm
Temporomandibular dysfunction is a broad term used to describe:
dysfunctions associated with TMJ
What are some dysfunctions associated with TMJ?
Pain Popping reduced bite force reduced ROM with mouth open headaches tinnitus trigger points
Factors associated with TMD include:
stress/emotional disturbances daily oral parafunctional habits asymmetric muscle activity sleep bruxism chronic forward head posture C - Spine pathology
Deviations and deflections can result from:
differently shaped mandibular condyle heads or may indicate a pathology
Deviations are motions that produce:
“S” curve with depression or protrusion
Deflections are motions that produce a:
“C” curve with depression or protrusion
What occurs when a disc subluxes beyond articular eminence?
articular disc displacement
articular displacement can result in 2 ways. What are those?
Disc displacement with reduction
disc displacement without reduction
disc displacement with reduction is produces a:
CLICK during mandibular depression and mandibular elevation
Disc displacement without reduction means:
the disc does not relocate and the patient will demonstrate limited mandibular motion due to mechanical obstruction due to the disc
The later the click occurs in the opening phase (depression):
The greater degree of dislocation
Head and neck position can affect tension in the ______muscles, which can ultimately:
cervical; influence the function of the mandible
Many TMJ dysfunction symptoms are similar to those of individuals with:
primary cervical spine impairments
What should be examined in patients with TMJ complaints?
C - spine and upper quarter
