TMJ Flashcards
TMJ
Synovial
Condylar
Fibrocartilaginous surface (not hyaline)
Articular disc
Articular disc
Meniscus
Divides each joint into two cavities
Provides congruent contours and lubrication for the joint
Innervated along periphery but aneural and avascular in its intermediate (force bearing zone).
What movements happen in the upper cavity of the TMJ?
Gliding
Translation (sliding)
What movements occur in the lower cavity of the TMJ?
Rotation (hinge)
TMJ: rotation
Occurs from beginning to midrange of movement
Primarily occurs in the inferior joint space
Pterygoid draws meniscus anteriorly
Condylar head rotates (post glide) past disc
Opening mouth involved what two phases
Rotation
Gliding
TMJ: gliding
Second half of opening jaw. Necessary past 15°
Mostly superior joint space
Anterior translation of condyle and disc together along slope of articular eminence
TMJ: resting position
Slightly open
Lips touching
Teeth not touching
TMJ: closed packed
Teeth clenched
TMJ: capsular pattern
Limited opening
Centric occlusion
Relation of jaws and teeth when there is maximum contact of teeth
Position of jaw while swallowing
Median occlusal pattern
The position in which the teeth are fully interdigitated
TMJ actively displaces ….
Anteriorly and slightly laterally
Three Cardinal features of TMD
Orafacial pain
Restricted jaw motion
Joint noise
Hyoid bone
“Skeleton of the tongue”
Attachment for extrinsic tongue and infrahyoid muscles.
Provides reciprocal stabilization during swallowing.
Can affect shoulder and cervical function
TMJ innervation
Branches of auriculotemporal and masseteric branches of mandibular nerves.
Temporomandibular ligament
AKA lateral ligament
Restrains movement of lower jaw; prevents compression of tissues behind condyles.
Connect zygomatic arch and neck of mandible with joint capsule
Sphenoidmandibular ligaments
Attach sphenoid to mandible
Guide movement– keep disc, condyles and temporal bone firmly opposed.
Stylomandibular ligament
Connects styloid process of temporal bone to ramus of mandible
Specialized band of deep cerebral fascia with thickening if parotid fascia
Guide movement– keep disc, condyles and temporal bone firmly opposed.
How many deciduous teeth?
20
How many permanent teeth?
32
Pain in fully opened position
Probably extra-articular
Pain with biting firm objects
Probably intra-articular
Limited opening
Disc displaced anteriorly, inert tissue tightness, or muscle spasm.
Vertical dimension
Distance between to arbitrary points in the face, where is above and the other below the face.
Stiffness on waking, pain on function that improves over the day
Osteoarthritis
Mouth breathing
Tongue does not sit in proper position against the palate
Tongue normally provides internal pressure to shape the mouth; counterbalanced by buccinator and orbicularis oris complex.
Clicking/crepitus
Results from abnormal motion of disc and mandible.
Single click
Disc sticks early in opening, when condyle slides off rim into centre.
Clicks when it snaps into place.
Disc displacement with reduction
Partial anterior displacement of disc; needs to be overridden in order for condyle to reach normal open position (click)
(Can click again when re-subluxes)
Reciprocal clicking
First click when condyle moves along posterior border of disc
Normal function
When condyle moves back to posterior zone another click.
Bruxism
Clenching, grinding of teeth.
Can lead to facial, jaw, or tooth pain. Headaches.
Adhesive clicking after clenching.
TMD: stage 1
Disc slightly medial and anterior
Inconsistent click
Maybe pain. Maybe not
TMD: stage 2
Disc anterior and medial
Reciprocal click (early on opening; late on closing)
Severe constant pain
TMD: stage 3
Reciprocal constant click (later on opening; early on closing)
Most painful
TMD: stage 4
Click rare (disc no longer relocates)
No pain
Occlusal interference
Premature tooth contact that deflects jaw laterally and/or anteriorly.
During cervical flexion the mandible moves
Up and forward
During cervical extension the mandible moves
Back and down
With side flexion, maximum occlusion occurs
On the ipsilateral side.