Temporomandibular Joint

Question 1

Articular surfaces

Answer 1

1. Head of mandible: below.
2. Mandibular fossa: above.
3. Articular tubercle: above.
   Covered by white fibrocartilage.

Question 2

Joint type

Answer 2

1. Synovial.
2. Condylar.
3. Biaxial joint.

Question 3

Capsule above

Answer 3

1. Mandibular fossa margins.
2. Articular tubercle.

Question 4

Capsule below

Answer 4

Around mandible neck.

Question 5

Tempomandibular ligament

Answer 5

Lateral thickening of the capsule attached to articular disc margins.

Question 6

Articular disc

Answer 6

Oval plate of dense avascular fibrous tissue. It divides cavity into upper and lower compartments.

Question 7

Upper surface of articular surface

Answer 7

Concavoconvex

Question 8

Articular disc lower surface

Answer 8

Concave

Question 9

Articular disc periphery

Answer 9

Attached to capsule.
Receives lateral Pterygoid insertion.

Question 10

Tempomandibular ligament shape

Answer 10

Triangular

Question 11

Only proper ligament supporting the joint

Answer 11

Tempomandibular ligament

Question 12

Tempomandibular ligament above

Answer 12

Zygomatic arch tubercle

Question 13

Tempomandibular ligament below

Answer 13

Lateral and posterior surfaces of mandible neck.

Question 14

Stylomandibular ligament

Answer 14

Extends from Styloid process anterior surface TO Posterior border of angle and ramus mandible.

Question 15

Stylomandibular ligament function

Answer 15

It separates parotid from submandibular gland.

Question 16

Sphenomandibular ligament

Answer 16

Extends from Spine of Sphenoid TO Lingula of Mandible.

Question 17

TMJ movements

Answer 17

1. Depression
2. Elevation
3. Protraction
4. Retraction
5. Side to side movement

Question 18

Depression (opening mouth)

Answer 18

1. Simple hinge rotation of head downwards around horizontal axis.
2. Gliding movement of head and articular disc forward and downwards to lie below articular tubercle.

Question 19

Muscles producing depression

Answer 19

1. Lateral Pterygoid (gravity)
2. Digastric
3. Mylohoid
4. Geniohyoid
   Mylohyoid and Geniohyoid help lateral Pterygoid in resistance.

Question 20

Elevation (closing mouthocclusal position)

Answer 20

Reversed movement to depression.

Question 21

Muscle producing elevation

Answer 21

1. Temporalis
2. Masseter
3. Medial Pterygoid

Question 22

Protraction (forward movement)

Answer 22

Lower teeth are drawn forwards over upper teeth.

Question 23

Muscles producing protraction

Answer 23

1. Medial Pterygoid
2. Lateral Pterygoid
3. Masseter superficial fibers (small effect)

Question 24

Retraction (backward movement)

Answer 24

Mandible is drawn backwards to position of rest.

Question 25

Muscles producing retraction

Answer 25

Temporalis posterior fibers

Question 26

Side to side movement

Answer 26

1. Chewing
2. Grinding

Question 27

Muscles producing side to side movement

Answer 27

1. Medial Pterygoid
2. Lateral Pterygoid
   Of both sides alternatively

Question 28

TMJ nerve supply

Answer 28

1. Auriculotemporal nerve
2. Masseteric nerve
   From mandibular nerves

Question 29

TMJ blood supply

Answer 29

1. Superficial temporal artery
2. Maxillary artery
   From ECA

Question 30

Applied anatomy TMJ

Answer 30

Condyles are below articular tubercles when the mouth is opened. Sudden violence or muscular spasm (convulsive yawn) may displace one or both condyles into infratemporal fossa (anterior dislocation)
Reduction by depressing mandible posterior with elevating chin at the same time.