TMJ

Question 1

Components of TMJ

Answer 1

-mandibular condyle
– Articular eminence of temporal bone (mandibular fossa)
– fibrocartilage disc

Question 2

TMJ Disc

Answer 2

-attaches to medial and lateral poles of the condyle
-Attached anteriorly to lateral prerygoid

Anterior band: middle thickness, atnterior to condyle, no vascular supply

Intermediate band: smallest thickness, on top of condyle

Posterior band: thickest, on top of condyle with full mouth closure, attaches to retrodiscal tissue

Question 3

Inferior Joint

Answer 3

Functions as a hinge joint
-Rolls posterior during opening

Question 4

Superior Joint

Answer 4

Functions as a plain joint
-Slides anterior during opening

Question 5

Temporalmandibular ligament

Answer 5

Oblique: limits downward, and posterior motion
Horizontal: resist posterior motion
Both resist lateral displacement

Question 6

Stylomandibular ligament

Answer 6

Weakest, may limit protrusion

Question 7

Sphenomandibular ligament

Answer 7

May prevent forward translation

Question 8

Normal depression

Answer 8

– 40-50 mm
-Two fingers are functional, three fingers are normal

Question 9

Normal translation and rotation

Answer 9

First rotation: 11 to 25 mm of anterior rotation with a posteriorr roll
Translation: both condyle and disc have anterior slide

Question 10

Normal protrusion

Answer 10

6-9 mm

Question 11

Normal retrusion

Answer 11

3 mm

Question 12

Passive Disc Control

Answer 12

-retrodisc laminate applies traction posterior
-sphenomandibular lig

Question 13

Active Control of Disc

Answer 13

-superior lat pterygoid eccentrically contracts to control posterly
-Masseter attaches to anterolateral portion of disc to counteract lat pterygoid
-temporalis, med pterygoid, and masseter provide constant pressure on disc

Question 14

Normal Lateral Excursion

Answer 14

-8-11mm
-Ipsilateral condyle spins
-Contralateral condyle translates anteriorly

Question 15

Mandibular deviation

Answer 15

Mandible moves away from midline during depression, and stays there

Question 16

Mandibular deflection

Answer 16

Mandible moves away from midline during depression, but returns

Question 17

Muscles involved with depression

Answer 17

Digastric, suprahyoids, lower lateral pterygoid

Question 18

Muscles involved with elevation

Answer 18

Temporalis, masseter, medial pterygoid, superior lateral pterygoid

Question 19

Muscles of protrusion

Answer 19

Masseter, med and lat pterygoids

Question 20

Muscles of retrusion

Answer 20

Temporalis, with anterior digastric

Question 21

Muscles of lateral deviation

Answer 21

Contralateral Pterygoids, ipsilateral temporalis

Question 22

Longus Colli

Answer 22

-flexion and side bending with contra rot

Question 23

Longus Capitus

Answer 23

-flexion and side bending with ipsi rot

Question 24

Dentition

Answer 24

-contact of upper and lower teeth
-normal rest position with 1.5-5mm of space

Question 25

Anterior Disc Displacement: With reduction

Answer 25

-click during anterior translation with condyle stuck under disc
-2nd click when condyle slips from under disc when translating posteriorly

Question 26

Anterior Disc Displacement: Without reduction

Answer 26

-no clicks
-ligaments stretches and prevent relocation
-pain with movement