The TMJ

Question 1

list the muscles of mastication

Answer 1

Question 2

role of the masseter?

Answer 2

• elevates mandible
• protrudes mandible

Question 3

role of temporalis - anterior fibres?

Answer 3

elevate the Mandible

Question 4

role of temporalis - posterior fibres?

Answer 4

Fibres retract the Mandible

Question 5

role of superior lateral pterygoid?

Answer 5

Question 6

role of inferior lateral pterygoid?

Answer 6

Question 7

role of the medial pterygoid?

Answer 7

Mainly elevates the mandible

Question 8

what muscles does the sphenoid provide attachment for?

Answer 8

pterygoid

Question 9

label the blue part of the sphenoid

Answer 9

body

Question 10

label the green part of the sphenoid

Answer 10

lesser wing

Question 11

label the red part of the sphenoid

Answer 11

greater wing

Question 12

label the yellow part of the sphenoid

Answer 12

petrygoid process

Question 13

what is the outer pterygoid process section called?

Answer 13

lateral plate

Question 14

what is the inner pterygoid process section called?

Answer 14

medial plate

Question 15

where do lateral and medial pterygoid muscles both attach to?

Answer 15

lateral plate

Question 16

which aspect of the lateral pterygoid plate does the lateral pterygoid muscle attach to?

Answer 16

lateral aspect

Question 17

which aspect of the lateral pterygoid plate does the medial pterygoid muscle attach to?

Answer 17

medial aspect

Question 18

what type of joint is the TMJ?

Answer 18

complex synovial joint

Question 19

why is the TMJ named complex?

Answer 19

allows simultaneous movements at the same time

Question 20

where does the condyle of the mandible sit?

Answer 20

in the mandibular fossa of the temporal bone

Question 21

what is this arrow pointing to?

Answer 21

madibular fossa

Question 22

where does the joint capsule extend from into?

Answer 22

from temporal bone
all the way down to the neck of the mandible

Question 23

what is this middle arrow pointing to?

Answer 23

articular disc

Question 24

what does articular disc allow for?

Answer 24

smoothe movements

Question 25

what is the red arrow pointing to?

Answer 25

articular tubercle

Question 26

which bit do we aim to put the articular disc into when we open and close our jaw

Answer 26

articular tubercle

Question 27

name the 2 cavities the tmj is made out of

Answer 27

superior inferior

Question 28

what is the upper limit of the superior cavity?

Answer 28

mandiblar fossa

Question 29

sandwiched in the middle - what makes up the inferior boundary of the superior cavity?

Answer 29

articular disc

Question 30

sandwiched in the middle - what ALSO makes up the superior boundary of the inferior cavity?

Answer 30

articular disc

Question 31

what is the inferior boundary bordered by?

Answer 31

mandibular head

Question 32

what is the upper arrow pointing to?

Answer 32

superior articular cavity

Question 33

what is the upper arrow pointing to?

Answer 33

inferior articular cavity

Question 34

what are the 2 diff movements at the TMJ?

Answer 34

- forward and backward movement (translation) - rotation

Question 35

what TMJ area undergoes rotation and antero-posterior translation as the mouth opens and closes?

Answer 35

head of the mandible

Question 36

What movement does the head of the mandible undergo as the mouth opens and closes?

Answer 36

Rotation and antero-posterior translation.

Question 37

Which movement allows depression and elevation of the mandible?

Answer 37

Hinge movements.

Question 38

Which movement allows protrusion and retraction of the mandible?

Answer 38

Gliding movements.

Question 39

Q: What happens during protrusion of the jaw?

Answer 39

Translational movement takes place, where the teeth, condyles, and rami all move in the same direction and to the same degree.

Question 40

What type of movement is responsible for the forward and backward motion of the mandible?

Answer 40

Protrusion (forward) and retraction (backward).

Question 41

What is the direction of movement during elevation and depression of the mandible?

Answer 41

Depression is downward, and elevation is upward.

Question 42

What is the antero-posterior translation in TMJ movement?

Answer 42

A forward and backward sliding of the mandible's head during mouth opening and closing.

Question 43

What are the two main types of movement in the TMJ?

Answer 43

Hinge movements and gliding movements.

Question 44

which TMJ ligament is this?

Answer 44

joint capsule

Question 45

which TMJ ligament is this?

Answer 45

lateral ligament

Question 46

which TMJ ligament is this?

Answer 46

sphenomandibular ligament

Question 47

which TMJ ligament is this?

Answer 47

stylomandibular ligament

Question 48

Q: What is the function of the fibrous capsule in the TMJ?

Answer 48

A: The fibrous capsule is loose above the disc but tight below it.

Question 49

Q: What does the lateral ligament do in the TMJ?

Answer 49

A: It strengthens the lateral part of the TMJ.

Question 50

Q: How do the outer oblique fibers (OOP fibers) of the lateral ligament function?

Answer 50

hey stop the condyle from rotating further within the mandibular fossa and force it to jump out of the mandibular fossa onto the disc.

Question 51

Q: What causes the disc to move anteriorly in the TMJ?

Answer 51

A: Pulling of the lateral pterygoid muscle.

Question 52

Q: Where does the sphenomandibular ligament attach?

Answer 52

A: From the spine of the sphenoid to the lingula of the mandible.

Question 53

Q: What structures are related to the sphenomandibular ligament laterally?

Answer 53

A: The lateral pterygoid muscle, auriculotemporal nerve, and maxillary artery.

Question 54

Q: What structures are related to the sphenomandibular ligament medially?

Answer 54

A: Chorda tympani nerve and wall of the pharynx.

Question 55

Q: What pierces the lower end of the sphenomandibular ligament?

Answer 55

A: The mylohyoid nerve and vessels.

Question 56

Q: What is the stylo-mandibular ligament made of?

Answer 56

A: A thickened part of the deep cervical fascia.

Question 57

Q: What structures does the stylo-mandibular ligament separate?

Answer 57

A: The parotid and submandibular glands.

Question 58

Q: What is the function of the stylo-mandibular ligament?

Answer 58

A: It limits excessive protrusion of the mandible.

Question 59

Q: What does the Inner Horizontal Part (IHP) of the lateral ligament do?

Answer 59

Prevents excessive posterior displacement of the head of the mandible.

Question 60

Why is the Inner Horizontal Part (IHP) important for the TMJ?

Answer 60

It protects delicate vascular tissue posterior to the mandibular head and ensures the neck of the mandible breaks before the IHP does.

Question 61

What is the function of the Outer Oblique Part (OOP) of the lateral ligament?

Answer 61

Positions the condyle as the mouth opens and limits the stretch to shift the axis of rotation.

Question 62

What happens as a result of the Outer Oblique Part's (OOP) function?

Answer 62

The head of the mandible moves forwards onto the articular eminence.

Question 63

here does the sphenomandibular ligament (SML) attach?

Answer 63

From the spine of the sphenoid to the lingula of the mandible.

Question 64

What is the function of the sphenomandibular ligament (SML)?

Answer 64

Supports the role of the OOP in sliding and prevents excessive inferior displacement.

Question 65

Where does the stylomandibular ligament (STML) attach?

Answer 65

from the styloid process to the posterior portion of the ramus of the mandible.

Question 66

What is the possible function of the stylomandibular ligament (STML)?

Answer 66

May limit excessive protrusion of the mandible, though its function is unclear.

Question 67

name this component of the articular disc

Answer 67

Anterior Capsular Ligament – part of the joint capsule

Question 68

name this component of the articular disc

Answer 68

Superior Retrodiscal Lamina (elastic)

Question 69

name this component of the articular disc

Answer 69

Inferior Retrodiscal Lamina (inelastic)

Question 70

name this component of the articular disc

Answer 70

Retrodiscal Tissue. Highly vascular. Essential to joint integrity

Question 71

what is retrodiscal tissue essential for?

Answer 71

joint integrity

Question 72

Q: What is the role of the lateral and medial discal ligaments?

Answer 72

A: They keep the articular disc close to the condyle.

Question 73

Q: What are the two ligaments that anchor the articular disc?

Answer 73

A: Lateral discal ligament and medial discal ligament.

Question 74

Q: Which cavity of the articular disc is larger?

Answer 74

A: The superior cavity is much larger than the inferior cavity.

Question 75

Q: Where does rotation occur in the articular disc?

Answer 75

A: In the inferior cavity.

Question 76

Q: Where does translation occur in the articular disc?

Answer 76

A: In the superior cavity.

Question 77

Q: After rest has passed, what does the inferior head of the lateral pterygoid do during TMJ opening?

Answer 77

A: Rotates the mandible anteriorly.

Question 78

Q: What happens to the disc during TMJ opening?

Answer 78

A: The mandible pushes the disc anteriorly via the inferior head of the lateral pterygoid.

Question 79

Q: What is the role of the superior and inferior heads of the lateral pterygoid during TMJ opening?

Answer 79

A: Superior head relaxes, and the inferior head contracts.

Question 80

Q: Where does the mandibular head rest during TMJ opening?

Answer 80

A: On the articular eminence.

Question 81

Q: What happens to the disc during TMJ closing?

Answer 81

A: The superior retrodiscal lamina pulls the disc posteriorly until elastic tension is expended.

Question 82

Q: What happens to the lateral pterygoid heads during TMJ closing?

Answer 82

A: The superior head contracts, adding traction to the disc, while the inferior head relaxes.

Question 83

Q: What happens to the disc at the final stage of TMJ closing?

Answer 83

A: The disc snaps into place.

Question 84

Q: What is the position of the mandibular head during TMJ clicking?

Answer 84

A: It is in an abnormal position relative to the disc (posterior to the disc).

Question 85

Q: What causes the "click" sound in TMJ disorders?

Answer 85

A: The mandibular head snapping back into the correct position on the disc.

Question 86

Q: What is the function of the myotactic (stretch, jaw-jerk) reflex?

Answer 86

A: It maintains the resting position of the mandible by initiating muscle contraction when the mandible is stretched (e.g., due to gravity).

Question 87

Q: What triggers the myotactic reflex in the jaw?

Answer 87

A: Muscle stretch, such as gravity pulling the mandible downward.

Question 88

Q: What is the function of the nociceptive reflex in the jaw?

Answer 88

A: Protects teeth from damage by relaxing the muscles of mastication and contracting the digastric muscle to open the mouth.

Question 89

Q: What triggers the nociceptive reflex?

Answer 89

A: Pain caused by potentially damaging biting forces.

Question 90

Q: What happens to the muscles of mastication during the nociceptive reflex?

Answer 90

A: They relax.

Question 91

Q: Which muscle contracts during the nociceptive reflex to open the mouth?

Answer 91

A: The digastric muscle.