Temporomandibular Joint-Lecture Flashcards
1
Q
Muscles opening the mouth (depresion of mandible)
A
- Latera (external) pterygoid -mandibular (CN V)
2
Q
Muscles closing the mouth (elevation of mandible or occlusion)
A
- Masseter -Mandibular nerve (CN V)
- Temporalis -(CN V)
- Medial (internal) pterygoid -(CN V)
3
Q
Muscles for protrusion of mandible
A
- Lateral (external) pterygoid -Mandibular nerve (CN V)
- Medial (internal) pterygoid -Mandibular nerve (CN V)
4
Q
Muscles for retraction of mandible
A
- Temporalis (posterior fibers) -Mandibula nerve (CN V)
5
Q
Muscles for lateral devation of mandible
A
- Lateral (external) ptreygoid ((ipsilateral muscle))
- Medial (internal) pterygoid ((contralateral muscle))
both mandibular nerve (CN V)
6
Q
Why is TMJ important?
A
- Without these joints we would severely be hindered in talking, yawning, eating, kissing, or sucking
- TMD is the second most commonly occurring musculoskeletal condition resulting in pain and disability (after chronic low back pain)
- Affects approx. 5-12% of the population
- Annual cost estimated at $4 billion
7
Q
TMJ joint- type
A
- modified hinge joint
8
Q
TMJ joint- articulation
A
- condyle of the mandible
- articular tubercle & mandibular fossa
9
Q
TMJ joint- capsule
A
- attaches to margins of articular area on temporal bone and around neck of mandible
10
Q
TMJ joint- features
A
- articular surfaces covered by fibrocartilage
- articular disc divides jt space into two compartments (two synovial membranes)
11
Q
TMJ lower compartment
A
- hinge-like movement (depression and elevation of the mandible)
12
Q
TMJ upper compartment
A
- forward (protrusion) and backward (retraction) movements of mandible –translation
13
Q
TMJ rotation movement
A
- Rotation occurs from the beginning to the midrange of movement
- Upper head of lateral pterygoid muscle draws the disc anterior to prepare for condylar rotation during movement
- Movement occurs between two condylar heads with disc in between
- **Importance of disc is to provide congruent contours and lubrication of joint
14
Q
TMJ translation movement
A
- Translation or gliding occurs during second half of range (Depression)
- Condyle and disc along the slope of the articular eminence
15
Q
Additional anatomy
A
- As the mandible moves forward on opening, the disc moves medially and posteriorly until the collateral ligaments and lateral pterygoid stop its movement. (Seating of disc)
- If seating does not occur, full ROM is limited
- lInnervation: Branches of the auriculotemporal and massenteric branches of the mandibular nerve
16
Q
Ligaments
A
- Temporomandibular / Lateral
- Sphenomandibular
- Stylomandibular
18
Q
Muscles of mastication- Temporalis
A
- Action: Elevation and retraction of mandible
- Origin: Bone of temporal fossa and temporal fascia
- Insertion: Coronoid process of mandible and anterior margin of ramus of mandible
19
Q
Muscles of mastication- Medial Pterygoid
A
- Action: Elevation and side to side movement of mandible
- Origin: Medial surface of lateral plate of pterygoid process and tuberosity and pyramidal process of maxilla
- Insertion: Medial surface of mandible near angle
20
Q
Muscles of mastication- Lateral Pterygoid
A
- Action: Protrusion and side to side movements of mandible
- Origin: Roof of infratemporal fossa and lateral surface of lateral plate of pterygoid process
- Insertion: Capsule of TMJ in region of attachment to the disc and to the pterygoid fovea on the neck of mandible
21
Q
Muscles of mastication- Masseter
A
- Action: Elevation of mandible
- Origin: Zygomatic arch and maxillary process of the zygomatic bone
- Insertion: Lateral surface of ramus of mandible
- *Deep and superficial parts
