2:hna B1: Tmj

Front 1

What are the two ligaments that try to be flexible and stabilizing?

Back 1

TMJ and shoulder

Front 2

1) Which way are the fibers of the joint capsule running? What is its function?

2) Why is it most important to prevent really forceful retrusion?

Back 2

1) Superoposterior to inferoanterior. If you protrude the mandible, it'll stop it. Impedes protrusion, allows retrusion.

2) If you slam the condyle backwards, you will hit the tympanic portion of the temporal bone and experience a lot of pain.

Front 3

1) What is the TMJ an articulation between?

2) What does the condyle of the mandible articulate with? What is in between and why it unique?

Back 3

1) The mandible and the temporal bone.

2) Meniscus between the condyle and the articulating surface of the temporal bone. Most synovial joints are bone-cartilage-bone, but *knee and TMJ are unique because they have a bone-meniscus-bone*

Front 4

1) What are the two categories of TMJ ligaments? What is their function? Are they involved in active joint movement?
2) Name the ligaments in each category.

Back 4

1) Functional and accessory. Passive restraint that limits and restricts border movement. NOT involved in active function!

2) Functional - temporomandibular (lateral) ligament, collateral ligament, capsular ligament
2) Accessory - sphenomandibular ligament and stylomandibular ligament

Front 5

Capsular ligament aka articular capsule aka TMJ capsule
1) Is if a functional or accessory ligament?
2) What does it enclose and what is its function?
3) What does the upper part of capsule consist of? Why is this unique?

Back 5

1) Functional
2) Entire TMJ. Extends anterior to include articular eminence, encompass the entire articular surface of the joint in order to retains synovial fluid within the joint. Also impedes protrusion
3) Fibrous + elastic tissue - only part of the capsule where both are found

Front 6

Capsular ligament aka articular capsule aka TMJ capsule

Where does it attach superiorly, posteriorly, anteriorly, and inferiorly?

Back 6

Superiorly - periphery of mandibular fossa.

Posteriorly - behind the squamotympanic fissure (separates mandibular fossa of the squamous portion of the temporal bone from the tympanic plate of the temporal bone).

Anteriorly - anterior slope of articular eminence

Inferiorly - periphery of the neck of the condyle

Front 7

Articular disc:

1) What is it formed from?
2) What collagen is it composed of and how is it arranged?
3) What does the anterior portion of the disc fuse with?
4) What is it also attached to?
5) What is notable about the posterior aspect?
6) What is the posterior region called?

Back 7

1) Inward extension of the joint capsule
2) Type 1 collagen bundles loosely arranged, except for the middle where they're organized in bundles. Small amount of type 3
3) Anterior and medial walls of the capsule
4) Lateral pterygoid
5) Divides into upper and lower portion
6) Bilaminar zone of the disc - retrodiscal area/retrodiscal pad

Front 8

Articular disc:

1) Vascularization?
2) How does it get nutrients?
3) What composes 5% of its dry weight?

Back 8

1) Majority avascular - but superior portion of bilaminar zone (posterior) has lots of blood vessels/flexible, inferior portion is avascular and inelastic.
2) Diffusion from synovial fluid, blood vessels located in the periphery
3) GAGs - 80% chondroitin sulfate, 15% dermatan sulfate

Front 9

Collateral ligament aka oblique band:

Type of ligament?
1) What does it attach?
2) Function?
3) What movement is this responsible for? What does it prevent?
4) What kind of tissue?

Back 9

Functional
1) Medial ligament attaches medial and lateral borders of articular disc to poles of the condyle.
2) Restrict movement of disc away from the condyle, allows disc to move anteroposteriorly with condyle and rotate anteroposteriorly on the articular surface of the condyle
3) Hinging movement - prevents posterior and inferior displacement of the condyle
4) Connective tissue

Front 10

Temporomandibular ligament:

1) Functional or accessory ligament?
2) What are its two portions?
3) Where the outer portion and what is its function?
4) Where is the inner portion and what is its function?

Back 10

1) Functional
2) Outer oblique portion, inner horizontal portion
3) OOP - articular tubercle and zygomatic process to outer surface of condylar neck. Limits the extent of mouth opening, impedes condyle from going backwards
4) IHP - articular tubercle and zygomatic process to lateral pole of condyle and posterior part of articular disc. Limits posterior movement of the condyle and disc

Front 11

What sits between the styloid process and mastoid process? What comes out of it?

Back 11

Stylomastoid foramen - facial nerve comes out of it

Front 12

Sphenomandibular ligament:

1) Functional or accessory ligament?
2) Developmental remnant of?
3) What does it run from?
4) Function?

Back 12

1) Accessory
2) Meckel's cartilage
3) Spine of sphenoid bone, lingula of the mandible
4) Small role in limiting lateral mandibular movement

Front 13

Stylomandibular ligament:

1) Functional or accessory ligament?
2) Origin and insertion?
3) What is its function?

Back 13

1) Accessory
2) Styloid process of occipital bone, angle of the mandible
3) Thickened anterior portion of the parotid capsule, separates the parotid gland from the infratemporal fossa, may limit protrusion of the mandible

Front 14

What is the primary sensory innervation of the TMJ? What other nerves carry sensory fibers?

Back 14

Auriculotemporal nerve is primary. Sensory branches of the mandibular nerve hop onto deep temporal nerve and masseteric nerve (MOTOR).

Front 15

1) Is the nerve to the masseter a sensory nerve?
2) Is the deep temporal nerve a sensory nerve?
3) Do sensory fibers hop off the mandibular nerve and on to the deep temporal nerve and masseteric nerve to supply sensory?

Back 15

1) no
2) no
3) yes

Front 16

1) What are the main branches of vascular supply for the articular capsule and temporomandibular ligament?

2) What makes the TMJ special with respect to the brainstem and proprioception/touch?

Back 16

1) Branches of the superficial temporal artery and maxillary artery as they pass by the joint capsule.

2) Mesencephalic nucleus of V has fibers for proprioception/touch from TMJ and muscles of mastication - they don't synapse in a ganglion

Front 17

1) Why is the TMJ unique with its meniscus?
2) Describe the structure of the meniscus anteriorly, intermediately, and posteriorly.

Back 17

1) Only joint in which the meniscus separates the internal aspect of the joint so there is an upper joint space and lower joint space.
2) Anterior lump, flattened intermediate zone, posterior disc band that fits neatly into glenoid fossa

Front 18

What are the articulations of the TMJ and mandible covered by? What are the only other synovial joints like this?

Back 18

Fibrous connective tissue with fibroblasts scattered throughout a dense layer of type I collagen. Fibrocartilage deep to this. It is NOT hyaline cartilage. Acromioclavicular, sternoclavicular joints.

Front 19

At rest, the condyle sits under what part of the meniscus?

Back 19

Posterior disc band.

Front 20

1) What is the function of the bilaminar region of the meniscus?
2) Why is the bilaminar zone unique?

Back 20

1) Cartilage that attaches meniscus to capsular ligaments on posterior aspect.
2) Has a vascular supply - needs to be constantly regenerated because the condyle is constantly moving posterior.

Front 21

What are the two motions involved when you open your mouth? What kind of joint does this make the TMJ?

Back 21

Mandibular condyle rotates slightly, condyle translates forward as well as the meniscus.

Ginglymoarthroidal joint - it hinges and slides

Front 22

Describe the process of the mouth opening.

Back 22

1) Mandibular condyle sits inferior to the posterior band of the meniscus
2) Mouth begins to open, condyle moves forward and lies underneath the intermediate zone
3) With mouth fully open, condyle lies inferior to the anterior band of the meniscus

Front 23

Function of the inferior and superior heads of the lateral pterygoid?

Back 23

Inferior head responsible for mandibular protrusion, superior head contracts when the mandible closes and prevents the condyle from slamming into the retrodiscal pad during mandibular elevation and retrusion.

Front 24

Temporalis:

1) Why do you have a headache if you have bruxism?
2) What do temporalis fibers do?
3) Where does it attach?

Back 24

1) You put your temporalis in spasm all night
2) **Primary elevator of mandible**, retrusion, lateral excursion
3) Past coronoid process down onto the ramus of the mandible, on the external and internal aspect. It's not just on the coronoid process, it's on the mandible too.

Front 25

1) What are the two heads of the masseter and what do they do?

2) Is the mandible the primary retruder of the mandible?

Back 25

1) Superficial (big) - elevate mandible, protrusion, lateral excursion
2) Deep head - retrusion when mandible is protruded

No - temporalis is primary, but masseter helps

Front 26

Where do the lateral and medial pterygoids originate from?

Back 26

Lateral - lateral aspect of the lateral pterygoid plate

Medial - medial aspect of the lateral pterygoid plate

Front 27

1) What is the function of the superior head of the lateral pterygoid?

2) What is the function of the inferior head of the lateral pterygoid?

Back 27

1) When condyle starts retruding, it contracts to prevent extreme retrusion, modulating the action of the temporalis and masseter. *Stabilizer during retrusion*

2) Protrusion, depression, medial excursion

Front 28

What 3 things prevent the condyle from hitting the tympanic portion of the temporal bone when it retrudes?

Back 28

1) Portion of TMJ ligament 2) Retrodiscal pad 3) Superior head of the lateral pterygoid

Front 29

1) Where is the medial pterygoid located relative to the masseter?
2) What are the actions of the medial pterygoid?

Back 29

1) Masseter is on the outside, medial pterygoid on the inside. It's in the pterygomasseteric sling
2) Elevation, medial excursion, protrusion

Front 30

What is the function of the sphenomandibularis?

Back 30

Protrude, medial excursion, elevate mandible