TMJ

Question 1

What is the temporomandibular joint (TMJ)?

Answer 1

joint where the mandible articulates with the base of the cranium

Question 2

What do the condyles of the mandible fit into?

Answer 2

articular fossa

Question 3

What fossa on the squamous part of the temporal bone are related to the TMJ?

Answer 3

mandibular fossa
glenoid fossa
articular fossa

Question 4

What separates the condyle of mandible and squamous part of the temporal bone in the TMJ?

Answer 4

articular disc

Question 5

What is the mediolateral length of the condyle of mandible compared to the anteroposterior width?

Answer 5

ML is twice as long

Question 6

What is a compound joint?

Answer 6

• more than three bones

Question 7

What are the three parts of the TMJ compount joint?

Answer 7

condyle
temporal
articular disc

Question 8

What is a complex joint?

Answer 8

allows for more than one type of movement

Question 9

What is a synovial joint?

Answer 9

contains synovial fluid

Question 10

What is a ginglymoarthrodial joint?

Answer 10

hinging movement (ginglymoid)
and
gliding movement (arthrodial)

Question 11

What type of movement does the arthrodial joint allow for?

Answer 11

translation movement only
- gliding

Question 12

What type of movement does the gingylmus joint allow for?

Answer 12

rotational movement only
- hinging

Question 13

What type of movement does the gingylmoarthrodial joint allow for?

Answer 13

rotational and translational

Question 14

What is the articular disc made of?

Answer 14

fibrous connective tissue

Question 15

What type of joint is the TMJ?

Answer 15

• compound joint
• complex joint
• gingylmoarthrodial joint

Question 16

What is the shape of the articular disc?

Answer 16

inferior part - concave
superior part - concavo-convex

Question 17

What are the characteristics of the articular disc?

Answer 17

non-innervated
avascular
somewhat flexible
dense fibrous connective tissue

Question 18

What are the three sagittal sections of the articular disc?

Answer 18

anterior zone
middle/intermediate zone
posterior

Question 19

What is the order of the sagittal sections of the articular disc from thickest to thinnest?

Answer 19

posterior > anterior > middle

Question 20

Articular surface of the condyle functions on the _____________ zone of the disc

Answer 20

intermediate

Question 21

What are the frontal sections of the articular disc?

Answer 21

medial and lateral

Question 22

Is the articular disc thicker medially or laterally?

Answer 22

medially

Question 23

What attaches the articular disc to the medial and lateral poles of the condyle?

Answer 23

discal/collateral ligaments

Question 24

What are the histological zones of the articular surfaces in the TMJ?

Answer 24

• articular zone
• proliferative zone
• fibrocartilaginous zone
• calcified zone

Question 25

What are the characteristics of the articular zone of the articular disc?

Answer 25

- dense fibrous connective tissue - most superficial layer - less susceptible to aging - better ability to repair

Question 26

What are the characteristics of the proliferative zone of the articular disc?

Answer 26

- undifferentiated mesenchymal cells - responsible for proliferation in response to loads

Question 27

What are the characteristics of the fibrocartilaginous zone of the articular disc?

Answer 27

- 3D network of collagen - resistance to lateral and compressive forces

Question 28

What are the characteristics of the calcified zone of the articular disc?

Answer 28

- chondrocytes - chondroblasts - active site for bone remodeling

Question 29

What are the areas of a synovial joint that aren't involved in articulation covered in?

Answer 29

specialized endothelial cells that form the synovial lining

Question 30

What does synovial fluid provide?

Answer 30

metabolic requirements and lubrication

Question 31

What is weeping lubrication of synovial fluid?

Answer 31

articular surfaces absorb some of the fluid, increased absorption during function, metabolic exchange

Question 32

What is boundary lubrication of synovial fluid?

Answer 32

movement of fluid from one area of the joint cavity to another, prevents friction

Question 33

What nerve innervates the TMJ?

Answer 33

mandibular branches of the trigeminal nerve (auriculotemporal and masseteric)

Question 34

What artery supplies the TMJ?

Answer 34

superficial temporal artery (branch of the external carotid artery)

Question 35

What are the articular disc attachments?

Answer 35

- posterior (superior retrodiscal lamina, inferior retrodiscal lamina) - anterior (SH lateral pterygoid, superior anterior attachment, inferior anterior attachment) - capsular ligament (anterior, posterior, medial, lateral)

Question 36

What are the posterior attachments of the artiuclar disc?

Answer 36

superior retrodiscal lamina inferior retrodiscal lamina

Question 37

What are the characteristics of the superior retrodiscal lamina?

Answer 37

- to the tympanic plate - connective tissue - elastic fibers - stretches as joint is moved forward

Question 38

What are the characteristics of the inferior retrodiscal lamina?

Answer 38

- collagenous attachment (not elastic) - to the posterior margin of the articular surface of the condyle

Question 39

What are the anterior attachments of the articular disc?

Answer 39

- superior head of the lateral pterygoid - superior anterior attachment - inferior anterior attachment

Question 40

What are the characteristics of the superior anterior attachment?

Answer 40

- to the capsular ligament - to the anterior margin of the articular surface of the temporal bone

Question 41

What are the characteristics of the inferior anterior attachment?

Answer 41

- to the capsular ligament - to the anterior margin of the articular surface of the condyle

Question 42

What is the superior joint cavity bordered by?

Answer 42

glenoid fossa superior aspect of the disc

Question 43

What is the inferior joint cavity bordered by?

Answer 43

inferior aspect of the disc superior aspect of the condyle

Question 44

Which joint compartment of the TMJ does rotation occur in?

Answer 44

inferior joint compartment

Question 45

Which joint compartment of the TMJ does translation occur in?

Answer 45

superior joint compartment

Question 46

What are the functional ligaments of the TMJ?

Answer 46

– Collateral/Discal ligaments – Capsular ligament – Temporomandibular ligament

Question 47

What are the accessory ligaments of the TMJ?

Answer 47

– Sphenomandibular ligament – Stylomandibular ligament

Question 48

What are the characteristics of the capsular ligament?

Answer 48

* Ligament that surrounds the joint like a curtain * Attached to the base of the skull and the condyle * Attached at the periphery of the articular parts * Also attached to the disc medially and laterally * Retains synovial fluid

Question 49

What are the characteristics of the temporomandibular ligament?

Answer 49

- thickening of the capsular ligament of the lateral aspect - from articular tubercle and zygomatic process to the lateral pole and neck of the condyle and disc

Question 50

What are the two parts of the temporomandibular ligament?

Answer 50

outer oblique inner horizontal

Question 51

What is the function of the outer oblique part of the temporomandibular ligament?

Answer 51

- prevents over rotation of the mandible - translation of the mandible after 20-25 mm

Question 52

What is the function of the inner horizontal part of the temporomandibular ligament?

Answer 52

- limits posterior movement onto the highly innervated retrodiscal tissue (PAIN) - prevent excessive overextension of the lateral pterygoid muscle

Question 53

What are the characteristics of the sphenomandibular ligament?

Answer 53

- from the spine of the spheniod bone - inserts onto the medial surface of the ramus of the mandible (lingula)

Question 54

What are the characteristics of the stylomandibular ligament?

Answer 54

- from styloid process - inserts into the posterior border of the ramus of the mandible - limits excessive protrusive movement of the mandible

Question 55

What is the origin and insertion of the sphenomandibular ligament?

Answer 55

O: angular spine of sphenodi bone I: mandibular lingula

Question 56

What is the origin and insertion of the stylomandibular ligament?

Answer 56

O: styloid process I: angle of mandible

Question 57

How long is the mediolateral length of the condyle of mandible?

Answer 57

15-20 mm

Question 58

How long is the anteroposterior width of the condyle of mandible?

Answer 58

8-10 mm