Lecture 8: TMJ Joint Final? Flashcards

1
Q

Key considerations for mastication

A

involves chewing, tearing, teeth grinding, speaking, and swallowing

interaction between CNS and muscles

TMJ = one of the most used joints of the body

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2
Q

bones involved in mastication

A

mandible
maxilla
temporal bone
sphenoid bone
hyoid bone

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3
Q

where can you palpate the mandibular condyle

A

just anterior to the external auditory meatus

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4
Q

what is the temporal fossa

A

slightly concave region

formed by parietal, temporal, frontal, sphenoid, and zygomatic bones

attachment for temporalis muscle

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5
Q

describe characteristics of the mandible

A

largest of facial bones
very mobile
suspended by ligaments/capsule and muscles
many landmarks

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6
Q

describe characteristics of the maxilla

A

R and L sides fuse
it is fixed
forms the floor of nasal cavity and the orbit of the eyes

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7
Q

key considerations for the sphenoid bone

A

it does not contribute to the TMJ structure

it does provide proximal attachments for medial and lateral pterygoid muscles

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8
Q

hyoid bone is anterior to what

A

C3

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9
Q

describe the osseous structures of the TMJ joint

A

flattened front to back (condyle) thin dense layer of fibrocartilage (better at absorbing force than hyaline with superior reparative process)

medial and lateral poles

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10
Q

describe the mandibular fossa

A

it is articular (sloped anterior wall), load bearing, thin/compact bone, and lined with fibrocartilage

full opening - they condyle slides forward (~50 degrees) across this opening with shear and compression forces

superior and posterior areas are non-articular, thin, and non load bearing

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11
Q

capsular structures in the TMJ joint

A

loose fibrous capsule
synovial membrane
capsule is firm medially/laterlaly and provides support

lax anterior to posterior to allow mouth opening

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12
Q

ligamentous estrutures of the TMJ joint

A

lateral ligaments stabilize

have oblique and horizontal fibers

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13
Q

what osteokinematics take place at the TMJ joint

A

protrusion: mandible translates anterior without rotation
recursion: reverse

lateral excursion: side to side (contralateral and ipsilateral); average 11mm max unilateral

depression and elevation: avg opens about 45-50 mm; typical mastication is 18mm

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14
Q

describe the arthrokinematics of the TMJ joint

A

combo of rotation and translation

rotation: mandibular condyle rotates relative to the inferior surface of the disc

translation: the mandibular condyle and disc slide together

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15
Q

what arthrokinematics take place in the TMJ joint with protrusion and retrusion

A

mandibular condyle and disc translate anterior/posterior

1.25 max

follows the slope of articular prominence (i.e. protrusion = anterior and downward)

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16
Q

describe the arthrokinematics of the TMJ joint with lateral excursion

A

side to side translation

mandibular condyle on the lateral excursion serves as a pivot point with contralateral condyle making a wider arc of rotation

17
Q

describe the arthrokinematics of the TMJ joint with depression and elevation

A

combo of rotation and translation
axis is constantly moving
no set radio of rotation/translation

early and late phase movements

18
Q

describe the arthrokinematics of the TMJ joint with depression and elevation

A

combo of rotation and translation
axis is constantly moving
no set radio of rotation/translation

early and late phase movementsdesci

19
Q

describe the arthrokinematics of the TMJ joint doing the early phase of depression/elevation

A

35-50% primarily rotation

posterior rotation on concave inferior surface of the disc

mandible goes inferior/posterior

20
Q

describe the arthrokinematics of the TMJ joint during the late phase of depression/elevation

A

final 50-65%

primarily translation (1.5-2mm)

condyle and disc slide forward and inferior along the articular eminence

closing is reverse (tension in retrodiscal lamina helps)

21
Q

innervation of the muscles of the TMJ joint

A

primary muscles = mandibular nerve (division of the trigeminal nerve- CN V)

sensory is from 2 branches of the mandibular nerve

22
Q

what are the primary muscles of mastication

A

masseter
temporalis
medial pterygoid
lateral pterygoid

23
Q

describe the masseter

A

thick, strong,
zygomatic arch to ramus of mandible,
line of force is perpendicular
large forces to crush food

24
Q

describe the temporalis muscle

A

flat fan shaped
through space to anterior and medial ramus
elevates

25
describe the medial pterygoid
nearly parallel to the masseter internal surface of ramus bilateral elevation and unilateral/contralateral excursion
26
describe the lateral pterygoid
2 heads travels horizontally unilateral is contralateral excursion bilateral strong protrusion
27
max human biting force
422 N (95 lbs)
28
what are the secondary muscles of mastication
supra hyoid: can assist with depression of mandible, speech/tongue movement, swallowing, and managing food bolus infra hyoid: stabilizes
29
describe TMJ disorders
broad and vague impairment of muscles, joints, ligaments, and discs often from teeth grinding or FHP (and sometimes OA) most cases are self limiting
30
what are signs and symptoms of TMJ disorders
popping reduced bite force reduced open range locking headaches tinnitus facial/scalp pain