Infratemporal Fossa II

Question 1

What is within the synovial joint? What is each of the structures function?

Answer 1

• Synovial membrane (for lubrication)
• Articular cartilage (to withstand loads)
• Joint cavity (for free movement)
• Articular disc (shock absorber)
• Fibrous capsule (for joint integrity)
• Also contains ligaments (for stability)

Question 2

What is the type of cartilage in the TMJ?

Answer 2

fibrocartilage

Question 3

The TMJ forms adjacent to the

Answer 3

intramembranous bone

Question 4

what makes up the joints of the body structure of the TMJ?

Answer 4

Mandibular condyle & fossa

Question 5

What are structures surrounding the TMJ?

Answer 5

Postglenoid spine, articular eminence, articular tubercle

Question 6

What are the ligaments associated w/ the TMJ?

Answer 6

Lateral ligament, sphenomandibular ligament, stylomandibular ligament

Question 7

Where does the lateral ligament attach? Is it strong or weak?

Answer 7

Attaches to posterior end of zygomatic arch (specifically to the articular tubercle)

It’s the strongest of the 3 ligaments

Question 8

Location of the sphenomandibular ligament? What’s its function? Is it strong or weak?

Answer 8

Runs from sphenoid spine to lingula of mandible

Plays a minimal role in limiting mandibular movement b/c it doesn’t extend w/ mandibular movement

It’s the 2nd weakest of the 3 ligaments

Question 9

Location of the stylomandibular ligament? What’s its function? Is it strong or weak?

Answer 9

Runs from styloid process to inferior aspect of mandible

Limits excessive protrusive movement of mandible

It’s the weakest of the 3 ligaments

Question 10

Where’s the synovial membrane present?

Answer 10

Located in the folds of the joint cavity, where no friction occurs

Question 11

What are the 2 basic cell types that form the synovium? What’s their function?

Answer 11

Synoviocytes
- Production of synovial fluid, which lubricates joint surfaces & nourishes chondrocytes

Synovial cells
- Phagocytosis, degradation, & removal of debris in joint cavity

Question 12

Anterior & posterior attachment of the articular disc

Answer 12

Attachment anteriorly: to superior head of lateral pterygoid plate
Attachment posteriorly: neck of condyle inferiorly & glenoid spine

Question 13

What are the different regions within the articular disc?

Answer 13

anterior band, posterior band, & intermediate zone between the 2

Question 14

The bilaminar zone (retrodiscal pad) is sandwiched between ___. What’s its function?

Answer 14

superior & inferior lamina

Facilitates great exchange of fluids & production of synovial fluid by synovial membrane

Question 15

Function of the superior & inferior lamina

Answer 15

Superior lamina
- Allows the disk & condyle to travel far
- contains elastic fibers

Inferior lamina
- Contains collagen
- Limits anterior sliding of disk along condyle

Question 16

Are the bilaminar zone & the disc vascular?

Answer 16

Bilmaniar zone is vascular
Disc is avascular

Question 17

At full opening, the pad is expanded ___ times its jaw closed volume

Answer 17

4-5

Question 18

Blood supply to the TMJ comes from the

Answer 18

superficial temporal artery

Question 19

What are the sources of innervation to the joint? Where do they supply to?

Answer 19

Masseteric nerve (supplies anterior aspect of TMJ) & auriculotemporal nerve (supplies posterior aspect of TMJ)

Question 20

Does the disk have innervation?

Answer 20

no

Question 21

R & L TMJs are connected to each other by the

Answer 21

mandible

Question 22

What muscle acts to produce movements of the TMJ?

Answer 22

lateral pterygoid muscle (superior & inferior head)

Question 23

Describe movement of the articular disc during opening/closing movements of the lower jaw in relation to the lateral pterygoid muscle

Answer 23

• When inferior head contracts, it pulls the condyle superiorly
• When superior head contracts, it pulls the disk forward

Question 24

What are the 2 types of movements at the TMJ?

Answer 24

• Rotation of condyle (hinge) & jaw drops - Up down rotation of condyle relative to the disk
• Translation (sliding) - Disk slides (w/ condyle) back & forth that’s facilitated by lateral pterygoid muscle

Question 25

Mechanical displacement of the articular disk results in

Answer 25

abnormal relationship of the disk to the condylar head & articular eminence
- Disk is located anterior to condyle head

Question 26

Describe anterior disk displacement

Answer 26

posterior band of the disc located anterior to the superior portion of the condyle at closed mouth on oblique sagittal images

Question 27

Describe anterior displacement w/ reduction & w/o reduction

Answer 27

w/ reduction = opened mouth position disc may be in a normal position
- you hear a “click” sound
w/o reduction = continue to be displaced

Question 28

Describe posterior disk displacement

Answer 28

condyle slides anteriorly to anterior eminence

Question 29

Sounds in TMJ occur in ___ of the population & pain is in ___ of the population. Are they more common in men or women?

Answer 29

30-50%
6-12%
women (4:1 to 6:1)

Question 30

When the mouth is closed, where is the disk in relation to the condyle?

Answer 30

Resting above the condyle

Question 31

Forces are transmitted to the ___ during chewing & biting

Answer 31

Condyle