chapter 5 tempromandibular joint Flashcards
tmj is classified as a
ginglymoarthrodial joint
a joint having the form of both ginglymus and athrodia joints, or hinge and sliding joints
ginglymoarthrodial joint
tmj is innervated by the
auriculotemporal and masseteric branches of mandibular nerve(or third division) of 5th cranial nerve or trigeminal nerve
tmj motor function by
muscles of mastication
area where the bones are joined to each other
articulation
lower of lower jaw
depression of mandible
raising of lower jaw
elevation of mandible
site of a junction of union between two or more bones
joint
shifting of the lower jaw to one side
lateral deviation of mandible
band of fibrous tissue connecting bones
ligament
type of body tissue that shortens under nerual control, causing soft tissue and bony structures to move
muscle
bringing forward of the lower jaw
protrusion of mandible
bringing backward of lower jaw
retraction or retrusion of mandible
acute episode in which both joints become dislocated, often due to excessive mandibular protrusion and depression
sublaxation
disorder involving one or both temporomandibular joiints
TMD
inability to normally open the mouth
trismus
forms upper and lower joint space or synovial cavities, avascular except posterior portion, poor healing, superior head of lateral pterygoid attaches to it medially
disc(meniscus) biconcave cartilage
enclosed the joint and spaces
joint capsule
3 ligaments of the joint
temporomandibular, stylomandibular, sphenomandibular
major support ligament, joint capsule blends with ligament on anterior lateral surface
temporomandibular ligament
attachments of temporomandibular ligament
zygomatic process of temporal bone, lateral surface of condylar neck
attachments for stylomandibular ligament
styloid process, medial angle of mandible
sphenomandibular ligament attachments
sphenoid bone and lingula; inferior alveolar nerve passes between ligament and mandible
the only gliding and rotating joint in the body
tmj
opening of tmj in multiple planes
opening and closing, protrusion and retrusion, lateral excursion/deviation
this movement occurs 1st, mandible rotates against disc, first 20 mm of mandibular opening
rotational movement
this movement occurs 2nd
gliding movement
mandible and disc glide down articular eminence, allows for remaining open
gliding movement
maximum opening
50-60mm
normal opening
anything 40mm or above
opening is a combination of
depression and protrusion of mandible
opening muscles
lateral pterygoids and suprahyoid
closing muscles
temporalis, masseter, medial pterygoid
closing is what movements(combination of)
elevation and retraction of mandible
what 2 movements occur throughout speech and mastication
lateral deviation and protrusion
ipsilateral condyle rotates, contralateral condyle moves forward and down eminence, contralateral lateral pterygoid muscle causes movement
lateral movement
example of left lateral movement:
- left(ipsilateral) condyle rotates
- right(contralateral) condyle moves forward and down eminence
- right(contralateral) lateral pterygoid muscles causes movement
involves translation or gliding of both joints down articular eminence
protrusive movements
muscles of protrusive movements
bilateral contraction of lateral pterygoids
muscles of retrusion
temporalis muscle
does mandible move up or down to eat?
no
do teeth touch when resting?
no
resting space/freeway space
2-4mm of space between teeth resting
loss of teeth does what to freeway space?
alters freeway space
the stylomandibular ligament separates
parotid and submandibular salivary gland
two basic types of movement for tmj
gliding(sliding) and rotational(or hinge)
movement occurs mainly between the disc and the mandibular condyle in the lower synovial cavity
rotation
occurs mainly between the articular eminence of temporal bone in the upper synovial cavity, with the disc plus the condyle moving forward or backward, and down and up articular eminence
gliding(sliding)
gliding movement involves
protrusion or retraction of mandible
movements accomplished with rotation
depression or elevation of mandible
during mastication what movement
laterally deviated position back to the midline
muscles involved with depressing mandible
anterior suprahyoid muscles
protrusion of mandible, moving mandible forward movement and muscles
gliding in both upper synovial cavities; lateral pterygoids with bilateral contraction
retraction of mandible, moving it backwards
movement and muscles
gliding in both upper synovial cavities; posterior part of temporalis and suprahyoid with bilateral contraction
elevation and retraction of mandible, closing jaws
movement and muscles
gliding in both upper synovial cavities and rotation in both lower synovial cavities; masseter, temporalis, medial pterygoid with bilateral contraction
depression and protrusion of mandible, opening jaws
gliding in both upper synovial cavities and rotation in both lower synovial cavities; suprahyoid and lateral pterygoids with bilateral contraction
lateral deviation of mandible to shift mandible to contralateral side
gliding in one upper synovial cavity and while the condyle and disc of other side spin around an approximately vertical axis within upper synovial cavity; lateral pterygoid with unilateral contraction
contact between teeth; relationship between the maxillary and mandibular teeth when they approach each other, as occurs during chewing or at rest
occlusion
the mesiobuccal cusp of the upper first molar occludes with the buccal groove of the lower first molar
normal occlusion
same as normal occlusion but characterized by crowding, rotations, and other positional irregularities
class 1 malocclusion
the mesiobuccal cusp of the upper first molar occludes anterior to the buccal groove of the lower first molar “overbite”. two subclasses
class 2 malocclusion
the mesiobuccal cusp of the upper first molar occludes posterior to the buccal groove of the lower first molar “underbite”
class 3 malocclusion
the relation of the mandible to the maxilla when the condyles are in the most superior and posterior position in the fossa
centric relation
the occlusion of opposing teeth when the mandible is in centric relation; this may or may not coincide with the maximal intercuspation
centric occlusion
the complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the “best fit of the teeth regardless of the condylar position”
maximal intercuspation
movement of the mandible while in centric relation, from
the initial occlusal contact into
maximum intercuspation
– The difference between CENTRIC OCCLUSION and
MAXIMAL INTERCUSPATION, if
there is a difference
centric slide
symptoms of tmd
pain, swelling, muscle spasms, limited movement and opening, clicking, popping, and locking of joint
causes of tmd
bone pathology(condylar changes, ankylosis), muscle and tendon pathology (temporalis tendonitis), nerve pathology(trigeminal neuralgia), inflammatory(infection, RA), noninflammatory (osteoarthritis), neoplasia(ex. tumors), disc pathology(perforations, dislocations)
most common causes of tmd
disc derangement/displacement and perforation
disc almost always displaced
anteriorly
disc derangement includes:
disc displacement with reduction, disc displacement without reduction, joint dislocation
disc stretches over time; moves in front of condylar head and limits movement; clicking and popping typical symptom, mri is used to diagnose disc disorder
disc displacement
hearing and palpating joint noises during opening and closing, protrusive opening and closings stop the reciprocal click
disc displacement with reduction
history of clicking and popping with or without intermittent locking, complaint of limited mouth opening
disc displacement without reduction
