Foundation Structures

Question 1

3 planes of mand motion

Answer 1

Midsagittal- down midline

Transverse- horizontal, top to bottom

Coronal- frontal, front and back

Question 2

TMJ moves in the

Answer 2

Transverse, horizontal plane

Question 3

TMJ

Answer 3

Area where mand condyle articulates at the base of cranium w temporal bone squamous portion

Question 4

Bones of skull

Answer 4

Temporal (zygomatic process)
Sphenoid
Zygomatic (cheek bone)
Mandible (condyle and coronoid processes)

Question 5

What muscle inserts on the coronoid process? Condylar process?

Answer 5

Coronoid- temporalis

Condylar- lateral pterygoid

Question 6

What forms the inferior part of the TMJ

Answer 6

Condylar process of the mandible

Question 7

What does the rod through the typodont represent?

Answer 7

The transverse axis that the mandible rotates around

Question 8

What forms the upper portion of the TMJ

Answer 8

Mandibular fossa of the temporal bone

Question 9

Articulate eminence

Answer 9

Convex Area directly anterior to the mand fossa of the temporal bone

Question 10

STF

Answer 10

Squamo- tympanic fissure

Posterior roof of mandibular fossa

Question 11

Sphenoid bone

Answer 11

Middle portion of cranial base

Pterygoid process

Question 12

Why is pterygoid process important

Answer 12

Of sphenoid bone

Important because it is the origin for 3 mastication muscles

Question 13

Zygomatic bone

Answer 13

Cheek bone
Second most commonly fractured bone of face

Masseter origin

Question 14

Where does the masseter originate

Answer 14

Zygomatic bone

Question 15

What makes up the TMJ

Answer 15

Mandibular fossa of temporal bone
Articulate disc- dense fibrous CT
Condylar process of mandible

Question 16

What moves with the head of the condyle

Answer 16

The articulate disc

Question 17

Functions of the articular disc of TMJ

Answer 17

Splits TMJ into functional compartments
Upper= translation
Lower= rotation

Stabilizes condyle, Helps lubricate TMJ

Absorbs shock

Reduces physical wear/strain

Regulates movement

Question 18

Functional compartments of TMJ

Answer 18

Upper= translation

Lower= rotation

Split by the articular disc

Question 19

TMJ fibrous capsule

Answer 19

Tube of tissues that encloses TMJ

Inner layer secretes synovial fluid
Outer layer is thick tissue that protects and limits movement

Question 20

4 muscles of mastication

Answer 20

Masseter
Temporalis
Medial pterygoid
Lateral pterygoid

Question 21

Masseter

Answer 21

O= zygomatic arch
I= lateral angle of mandible 

Function- elevates mandible

Question 22

Temporalis

Answer 22

O= temporal fossa 
I= coronoid process of mandible and anterior Ramos 

Function- anterior elevates mandible, posterior retrudes the mandible

Question 23

Medial pterygoid

Answer 23

O= medial surface of lateral pterygoid plate of sphenoid 
I= medial angle of mandible 

Function- elevates mandible

Question 24

Lateral pterygoid upper vs lower

Answer 24

Upper
O= great wing of sphenoid bone
I= articular disc and condyle
Function= opens mandible, pulls articular disc forward

Lower
O= lateral pterygoid plate of sphenoid
I= neck of condyle
Function- symmetrical= opening and protrusion
Asymmetrical= lateral movement of mandible

Question 25

Articular disc attachments

Answer 25

Posterior- retrodiscal tissue (bilaminar zone), loose ct that is highly innervated/vascular that attaches disc to tympanic plate and capsule Anterior- lateral pterygoid Medial- condyle and capsule

Question 26

What is the position of the articular disc determined by

Answer 26

Elastic fibers of the retrodiscal tissue bulling back Vs Lateral pterygoid pulling forward

Question 27

A contraction of the right lateral pterygoid results is what movement of the mandible

Answer 27

A left movement

Question 28

Mandible movement in each plane

Answer 28

Sagittal- symmetrical movement of mandible, muscles on both sides are working, opening and closing Transverse- rotation terminal hinge movement is when mouth is all the way open without mand moving forward, 25 mm Translation- disc moves anteriorly to protrude mandible, about 10mm Complex movement- movement of the mandible that combine rotation and translation

Question 29

Posselts diagram

Answer 29

Extreme mand motion record Recorded in three planes and 3 points Aka incisor, molar, and condylar

Question 30

Retruded contact

Answer 30

RC Superior limit of terminal hinge movement Aka centric relation or centric occlusion

Question 31

Stages of opening

Answer 31

1. Pure rotational opening - rotational movement with condyles in terminal hinge position, without translation 2. Rotation and translation- condyle is positioned down articular eminence, slightly protrudes 3. Yawning- Extent of opening is limited by sphenomandibular ligament

Question 32

Anterior guidance

Answer 32

Occurs during protrusion when mandible moves and causes mand teeth to glide along lingual of max teeth, disoccluding posterior teeth

Question 33

Protrusive interference

Answer 33

Premature contact from MI to protrusive | Between mesial aspects of mand teeth and distal aspects of max teeth

Question 34

No slip from MI to RC?

Answer 34

Condyles are naturally in centric relation Optimal condylar position When MI = RC