TMJ

Question 1

What are the articular surfaces of the TMJ?

Answer 1

condyle, articular eminence and mandibular fossa

Question 2

Which two articulating surfaces of the TMJ are part of the temporal bone?

Answer 2

Mandibular fossa and articular eminence

Question 3

What is the bony lateral boundary of the TMJ?

Answer 3

zygomatic process of temporal bone

Question 4

What is the medial bony boundary of the TMJ?

Answer 4

spine of the sphenoid

Question 5

What is the anterior bony boundary of the TMJ?

Answer 5

articular eminence

Question 6

What features of the skull make up the the posterior bony boundary of the TMJ?

Answer 6

squamotympanic and petrotymapnic fissures and the tympanic plate

Question 7

Where does the loose capsule surrounding the entire joint attach?

Answer 7

It attaches the joint from the temporal bone to the neck of the mandible

Question 8

What are the superior attachments of the capsule?

Answer 8

Anteriorly arraches to the articular eminence and posteriorly attaches to the squamotympanic fissure

Question 9

What is the inferior attachment of the capsule?

Answer 9

the neck of the condyle

Question 10

What is the temporomandibular ligament?

Answer 10

A thick part of the capsule that forms the lateral ligament and prevents posterior and inferior displacement

Question 11

Extrinsic ligament (1 of 2)

Answer 11

Stylomandibular ligament-styloid process to the angle of the mandible

Question 12

Extrinsic ligament (2 of 2)

Answer 12

Sphenomandibular ligament-spine of the sphenoid to lingula of mandible

Question 13

Articular disc

Answer 13

A BI-concave disc made of fibrous tissue that separates the joint into UPPER and LOWER compartments with a synovial membrane lining EACH ONE

Question 14

Articular disc (characteristics)

Answer 14

avascular and possibly receives nourishment from the synovial fluid

Question 15

Posterior thickening

Answer 15

larger and sits atop the condyle when at rest

Question 16

Anterior thickening

Answer 16

smaller and sits below the articular eminence

Question 17

Intermediate zone

Answer 17

thin and lies between the posterior and anterior thickenings

Question 18

Articular disk attachment to capsule via…

Answer 18

superior and inferior sheets or lamellae that blend with the walls of the capsule

Question 19

The superior attachment of the capsule is (loose or tight)?

Answer 19

loose

Question 20

The inferior attachment of the capsule is (loose or tight)?

Answer 20

tight

Question 21

Rotation, or simple rotation of the condyles occurs in…

Answer 21

the lower compartment during the first 20-27 mm of opening

Question 22

Translation, or sliding of the condyles AND the disk onto the articular eminence always occurs for any except the most minimal opening of the mouth in…

Answer 22

the upper compartment

Question 23

Translation causes…

Answer 23

posterior recess of the inferior compartment to increase in size and anterior recess to decrease in size

Question 24

Sliding of the condyle onto the articular eminence causes…

Answer 24

the mandible to open

Question 25

Innervation of the TMJ

Answer 25

General sensory-V3 (auriculotemporal, masseteric and temporalis nerves)

Question 26

Blood supply of TMJ

Answer 26

External carotid (superficial temporal) and branches of the maxillary artery

Question 27

Muscles causing protrusion of the mandible

Answer 27

lateral pterygoid, medial pterygoid, superficial head of the masseter

Question 28

Muscles causing retrusion of the mandible

Answer 28

Temporalis and deep head of the masseter (from a protruded position)

Question 29

Muscles causing depression of the mandible

Answer 29

Lateral pterygoid (inferior head) and supra and infrahyoid muscles (gravity is the strongest depressor)

Question 30

Muscles causing elevation of the mandible

Answer 30

Temporalis, masseter and medial pterygoid

Question 31

Muscles causing right lateral excursion of the mandible

Answer 31

right masseter, right temporalis, left medial pterygoid and left lateral pterygoid

Question 32

Muscles causing left lateral excursion of the mandible

Answer 32

left masseter, left temporalis, right medial pterygoid and right lateral pterygoid

Question 33

Note on excursive movements of the mandible (1 of 2)

Answer 33

the masseter and temporalis will pull the mandible to the same side becuase their origines are slightly LATERAL to their insertions

Question 34

Note on excursive movements of the mandible (2 of 2)

Answer 34

The medial and lateral pterygoids will pull the mandible to the opposite side becuase their origins are slightly MEDIAL to their insertions

Question 35

Swallowing and deglutition

Answer 35

Stage one (voluntary) Stages two through four (involuntary)

Question 36

Stage one of swallowing

Answer 36

Voluntary-food pressed into bolus on dorsum of tongue against hard palate. The swallow is initiated by pushing the food posteriorly into the oropharynx by the tongue

Question 37

Stage two of swallowing

Answer 37

Involuntary-Soft palate elevates to seal the oropharynx from the nasopharynx and prevents regurgitation of food into the nasal cavity. The stylopharyngeus and palatopharyngeus muscles and the suprahyoid muscles contract to raise the larynx

Question 38

Stage three of swallowing

Answer 38

Involuntary-The three constrictor muscles contract in a sequential fashion as peristaltic waves. From superior to inferior, each pair of muscles contracts for approx. .33 second. Just as the muscles physically overlap, so do their contractions overlap from superior to inferior.

Question 39

Stage four of swallowing

Answer 39

Involuntary-Bolus enters esophagus and is propelled downward by peristaltic action. Cricopharyngeus muscle is in a constant state of contraction and prevents passage of air to the esophagus below. During the act of swallowing, the cricopharyngeus relaxes to allow passage of the bolus into the esophagus below. The bolus is propelled to the stomach by peristaltic waves of the esophagus.