TMJ

Question 1

Components of TMJ

Answer 1

mandibular condyle
articular eminence and fossa
articular disc

Question 2

how large is the mandibular condyle?

Answer 2

25 mm wide (in men)

Question 3

what type of joint is TMJ? what type of movement does it do?

Answer 3

compound joint (involves multiple bones)

hinging and gliding

Question 4

is the articular fossa functioning or non-functioning?

Answer 4

non-functioning

Question 5

is the articular eminence functioning or non-functioning?

Answer 5

funcioning

Question 6

what is the role of the TMJ ligaments?

Answer 6

to support and limit movement

Question 7

4 TMJ ligaments

Answer 7

1. fibrous capsule (capsular ligaments)
2. lateral ligament (TMJ ligament)
3. stylomandibular ligaments
4. sphenomandibular ligament

Question 8

Fibrous capsule (capsular ligament)

Answer 8

controls excessive forward and downward (depression&protrusion) movement of mandible

Question 9

Lateral ligament (TMJ ligament)

Answer 9

reinforces capsular ligaments, limits lateral movement

Question 10

Stylomandibular ligaments

Answer 10

limits protrusion

Question 11

sphenomandibular ligament

Answer 11

limits depression (opening capacity)

Question 12

4 Muscles of Mastication

Answer 12

1. Masseter muscles
2. Temporalis muscles
3. Medial pterygoid muscles
4. Lateral pterygoid muscles

Question 13

Masseter muscle

Answer 13

elevatesmandible, closes teeth

origin: zygomatic arch
insertion: lat. surface of rami and angle of mandible

Question 14

Temporalis muscles

Answer 14

to elevate and retrude mandible (anterior/verticle fibers elevate, posterior/horizontal fibers retrude

origin: temporal fossa on cranium
insertion: coronoid process, anterior border of ramus and temporal crest

Question 15

Medial pterygoid muscles

Answer 15

elevate mandible, close teeth together

origin: pterygoid fossae (sphenoid)
insertion: medial angle of mandible

Question 16

Lateral pterygoid muscle

Answer 16

moves mandible laterally (alone), protrudes and depresses (with medial)

origin: lateral pterygoid plate (sphenoid), and Greater Wing
insertion: pterygoid fovea (condylar process), and anterior part of articular disc

Question 17

Other muscles affecting mandibular movement

Answer 17

1. suprahyoids
2. infrahyoids

together depress

Question 18

Innervation of muscles of mastication

Answer 18

trigeminal (CN V) division III mandibular branch

Question 19

Innervation of muscles of facial expression

Answer 19

Facial (CN VII)