Temporomandibular joint

Question 1

What type of joint is it?

Answer 1

Synovial

Question 2

What type of cartilage coats the bone surfaces?

Answer 2

Fibrocartilage which can grow and repair (a type of articular cartilage)

Question 3

What is the function of the articular disc?

Answer 3

Pressure absorbing device and splits joint into 2 compartments allowing 2 types of movement

Question 4

What surrounds the joint and attaches the bones?

Answer 4

Capsule ligament

Question 5

Between which bones does the joint form?

Answer 5

Mandibular condyle and temporal bone (mandibular fossa)

Question 6

What are the attachments of the capsule?

Answer 6

Mandibular fossa and articular eminence of the temporal bone superiorly.
To the neck of the condyle

Question 7

What is the temporomandibular ligament?

Answer 7

Lateral thickening of the capsule

Question 8

What are the attachments of the sphenomandibular ligament?

Answer 8

Spine fo. sphenoid to mandibular fo.

Question 9

What is the function for the sphenomandibular ligament.

Answer 9

Hinge movement meaning no rotation at the point the inferior alveolar nerved artery run

Question 10

What provides sensory innervation to the joint?

Answer 10

Branches of the auriculotemporal nerve, small anterior portion supplied by temporal branches of V3

Question 11

Why are there free nerve endings?

Answer 11

Send pain impulses to limit excessive movements of the mandible

Question 12

What provides the blood supply to the joint?

Answer 12

Branches from superficial temporal artery. Small anterior portion supplied by branches of maxillary artery

Question 13

What are the 2 types of movement about the joint?

Answer 13

Hinge and translation

Question 14

Where does the movement occur during the hinge movement?

Answer 14

Between condyle and disc = lower compartment

Question 15

What ligament is used during hinge movements?

Answer 15

Sphenomandibular ligament

Question 16

What moves during a hinge movement?

Answer 16

Condyle moves, disc stays stationary

Question 17

Where is the axis of rotation for hinge movements?

Answer 17

Mandibular fo.

Question 18

Where does the movement occur during a translatory movement?

Answer 18

Between disc and mandibular fossa (upper compartment)

Question 19

What moves during translation movement?

Answer 19

Condyle and disc move together

Question 20

What muscles move the jaw?

Answer 20

Supramandibular - muscles of mastication - massater, temporali, medial pterygoid, lateral pterygoid.
Inframandibular - supra hyoid and infra hyoid

Question 21

What muscles are used to open the jaw?

Answer 21

Inferior head of lateral pterygoid causes protraction.
Anterior digastric shortly after. Then gravity takes over.
Further opening first uses supra hyoids and platysma, then infra hyoids

Question 22

What muscles are used to close the jaw?

Answer 22

Massater, medial pterygoid and when closing against resistance uses temporals.
Superior head of lateral pterygoid then places condyle back into mandibular fossa

Question 23

At rest the jaw is held with teeth about 5mm apart, how is this maintained?

Answer 23

Using the muscles that close the jaw