Temporomandibular joint (TMJ) Flashcards
temporomandibular joint: articulation btw
temporal bone:
- articular process
- mandibular fossa
mandible:
- condyloid process
TMJ joint: classify
- synovial modified hinge
TMJ joint: function
- chewing
- talking
- yawning
TMJ joint: consists of
- fibrous capsule
- ligs
- articular surface + disc
- muscles
TMJ joint: articular capsule + disc
- loose
- margins of articular area of temporal bone
- neck of mandible
disc:
- separates into sup/ inf compartments
- compartments of synovial membrane
TMJ joint: name ligs and function
- lateral: (strengthens TMJ)
- stylomandibular lig (minimal support to joint)
- sphenomandibular lig (passive support to mandible)
TMJ joint: which lig prevents post dislocation
- lateral lig
lateral lig: from
reinforces around TMJ capsule in mandible
stylomandibular lig: from
styloid process to angle of mandible
sphenomandibular lig: from
sphenoid spine to lingula of mandibular foramen
TMJ joint: list movements
- elevation
- depression
- retraction
- protrusion
- lateral deviation (L, R)
TMJ joint: describe movement
- each condyle first rotates within disc
- both condyle and disc slide forward down articular eminence
- for jaw close: move in unison back into mandibular fossa
mm involved in: protrusion
- lateral pterygoid (assisted by medial pterygoid)
mm involved in: retraction
- post fibres of temporalis,
- deep part of masseter, glenohyoid and digastric
mm involved in: elevation
- temporalis
- masseter
- medial pterygoid
mm involved in: depression
- gravity
- digastric, glenohyoid, mylohyoid
mm involved in: mastication
- masseter
- temporalis
- lateral pterygoid
- medial pterygoid
mm involved in: suprahyoids
- mylohyoid
- geniohyoid
- stylohyoid
- digastric
mm involved in: infrahyoids
- sternohyoid
- omohyoid
- sternothyroid
- thyrohyoid
temporalis: origin
- bony surfaces temporal fossa
- inf temporal line
temporalis: insertion
- coronoid process
- ant margin or ramus and mandible
temporalis: action
vertical fibres:
- elevation, side to side
horizontal fibres:
- retraction
temporalis: function
- powerful elevator of mandible
- retraction
- assists w side to side movement
temporalis: shape
- fan shape
masseter: shape
- quadrangular
superficial part -masseter: origin
- maxillary process of zygomatic
- ant 2/3 zygomatic process maxilla
superficial part -masseter: insertion
- lateral aspect of ramus of mandible
superficial part -masseter: action
elevation
deep part -masseter: origin
- medial aspect of zygomatic arch
- post part of its inf margin
deep part -masseter: insertion
- central and upper part of ramus of mandible
- as high as coronoid process
deep part -masseter: action
elevation
deep head - medial pterygoid: shape
quadrangular
deep head - medial pterygoid: origin
- medial surface of lateral pterygoid plate/ process
deep head - medial pterygoid: insertion
- fibres pass down lateral
- post to common tendinous sling on medial side of ramus of mandible
deep head - medial pterygoid: action
elevation assists lateral pterygoid in protrusion
medial head - medial pterygoid: shape
quadrangular
deep head - medial pterygoid: origin
maxillary process and pyramidal process of palatine bone
deep head - medial pterygoid: insertion
- fibres pass down lateral, post to common tendinous sling on medial side of ramus of mandible
deep head - medial pterygoid: actino
elevation assists lateral pterygoid in protrusion
sup head - lateral pterygoid: shape
triangular
sup head - lateral pterygoid: origin
- infratemporal surface
- infratemporal crest of greater wing of sphenoid
sup head - lateral pterygoid: insertion
- articular disc and fibrous capsule
sup head - lateral pterygoid: action
protrusion coordinated movement of TMJ result in chewing
inf head - lateral pterygoid: shape
triangular
inf head - lateral pterygoid: origin
- lateral surface of lateral pterygoid plate/ process
inf head - lateral pterygoid: insertion
neck of mandible
inf head - lateral pterygoid: action
protrusion coordinated movement of TMJ result in chewing
innervation: masseter
trigeminal (CN V) mandibular division
- masseteric branch
innervation: temporalis
CN V mandibular div - deep temporal nerves
innervation: medial pterygoid
CN V mandibular div - medial pterygoid n
innervation: lateral pterygoid
CN V mandibular div - lateral pterygoid n
suprahyoid and infrahyoid mm: function
- primarily used to raise/ depress hyoid bone and larynx
- indirectly help depress mandible: suddenly/ against resistance
stylohyoid: origin
styloid process of temporal bone
stylohyoid: insertion
body of hyoid
stylohyoid: inn
facial (CN VII)
mylohyoid: origin
mylohyoid line on mandible
mylohyoid: insertion
body of hyoid, median raphe
mylohyoid: inn
n to mylohyoid from mandibular div of CN V
geniohyoid: origin
inf mental spine of mandible
geniohyoid: insertion
body of hyoid
geniohyoid: inn
ant rami of C1
diagastric: origin - ant belly
diagastric fossa of mandible
diagastric: origin - post belly
mastoid process of temporal bone
diagastric: insertion
intermediate tendon (body of hyoid)
diagastric: inn
CN VII
TMJ: innervation branch
auriculotemporal n. from mandibular branch of trigeminal
TMJ: auriculotemporal provides
- general sensory fibres from skin over large area of temple
- external ear
- tympanic membrane
- TMJ
- delivers postganglionic parasymp fibres to parotid gland
TMJ: signs and symptoms associated
- pain travelling through face/ jaw/ neck
- stiff jaw mm
- limited movement/ locking of jaw
- painful clicking/ popping of jaw
- change in position of sup/ inf teeth
TMJ: palpation
- intraoral (in mouth)/ TMJ palpation
- intra auricular
eg. Bruxism:
- nocturnal grinding of teeth
- causes inflammation/ pain
eg. ant disc displacement without reduction
- lock jaw decreased ROM
- ligs stretch, disc sits ant and doesn’t reduce back into mandibular fossa
- difficulty opening mouth more than 2 finger width
TMJ: dislocation
ant:
- large bites, excessive contraction of lateral pterygoid mm
post:
- uncommon due to protection of lateral lig
TMJ: stylomandibular lig sprain
- sharp to aching pain behind lower jaw and below ear
- bad bite or trauma
TMJ: arthritis features
- systemic disease like rheumatoid arthritis
- excessive use of TMJ
TMJ: arthritis symptoms
- crepitus (grating sound)
- pain around ear
- bit shift and decreased ROM
- inability to chew