2nd Session: Anatomy of the TMJ (1-15, Astorga)

Question 1

What is the Masticatory System responsible for?

Answer 1

Chewing, speaking, swallowing

Question 2

Masticatory system: name the skeletal components (MMT)

Answer 2

Mandible Maxilla Temporal

Question 3

Masticatory system: name the muscle components (6)

Answer 3

Masseter Temporalis Superior Lateral Pterygoid Inferior Lateral Pterygoid Medial Pterygoid Digastric

Question 4

Masticatory system: name the ligament components (CCTSS)

Answer 4

Collateral Capsular Temporomandibular Sphenomandibular Stylomandibular

Question 5

Name the main parts of the mandible bone:

Answer 5

Condyle, Coronoid Process, Ramus, Mandibular Notch, Mental Foramen, Body

Question 6

Name the anatomy on the temporal bone:

Answer 6

Mastoid Process

External Acousitc Meatus

Styloid Process

Glenoid fossa

Articular Eminence

Zygomatic Process

Squamous Portion

Question 7

Name the main anatomy of the maxilla bone:

Answer 7

Frontal Process,

Infraorbital Foramen,

Anterior Nasal Spine,

Alveolar Process, Body,

Tuberosity,

Infratemporal Surface,

Zygomatic Process

Question 8

Name the Origin, Insertion, Function, Vascularity, and Innervation of the masseter muscle.

Answer 8

O: Zygomatic process of the maxilla

I: Angle of the mandible

F: Elevation of the mandible & protrusive

Vas: masseteric artery

Innerv: Masseteric branch of CNV (Trigeminal)

Question 9

Name the Origin, Insertion, Function, Vascularity, and Innervation of the temporalis muscle.

Answer 9

O: Temporal fossa

I: coronoid process and anterior border of the ascending ramus

F: elevation of the mandible and retrusion

Vas: anterior, posterior, and superficial temproal arteries

Innerv: Deep temporal nerve from the mandibular branch of CNV (trigem)

Question 10

Name the Origin, Insertion, Function, Vascularity, and Innervation of the lateral superior pterigoid muscle.

Answer 10

O: Lower part of the lateral surface of the great wing of the sphenoid and from the intratemporal crest.

I: The neck of the condyle and the anterior margine of the DISC!

Function: stabilizes the condyle and disk curing mandible loading (unilateral chewing)

Vas: Pterygoid branch of the maxillary artery

Innerv: mandibular branch of the CNV (trigem)

Question 11

Name the Origin, Insertion, Function, Vascularity, and Innervation of the inferior lateral pterigoid muscle.

Answer 11

O: lateral surface of the lateral pterygoid plate

I: neck of the condyle

function: protrudes the mandible, contributes to the lateral movements and mouth opening
vas: pterygoid branch of the maxillary artery

Inn: mandibular branch of the CNV (trigem)

Question 12

Name the Origin, Insertion, Function, Vascularity, and Innervation of the medial pterygoid:

Answer 12

O: medial surface of lateral ptrygoid plate and the pyramidal process of the palatine bone.

I: inferior and posterior of the medial surface of the ramus and angle of the mandible

Function: elevation of the mandibl and contributes of protrusion

Vas: pterygoid branch of the maxillary artery

Innerv: mandibular branch of the CNV (trigem)

Question 13

Name the Origin, Insertion, Function, Vascularity, and Innervation of the anterior digastric muscle:

Answer 13

O: digastric fossa

I: Hyoid bone

Function: depression of the mandible and elevation of the hyoid bone

Vas: submental artery

Innerv: Mandibular branch of the CNV

Question 14

Name the Origin, Insertion, Function, Vascularity, and Innervation of the posterior digastric muscle:

Answer 14

O: mastoid notch

I: hyoid bone

function: depression and elevation of the hyoid bone
vas: lingual and facial artery

Innerv: digastric branch of the CNVII (facial)

Question 15

Do ligaments stretch?

Answer 15

Nope! But they can elongate over time, which compromises their function.

Question 16

What is the main way that ligaments function?

Answer 16

Ligaments are not an active functional component of joints, but act as passive restraining devices to limit and restric border movements.

Question 17

What are the three funciton ligaments that support the TMJ?

Answer 17

Collateral Ligaments

Capsular Ligaments

Temporomandibular Ligament (TML)

(The sphenomandibular and stylomandibular ligaments are accessory)

Question 18

What does the collateral ligament do?

Answer 18

Attaches the medial and lateral borders of the articular disk (MDL And LDL) to the poles of the condyle:

medial discal ligament (MDL)

and

lateral discal ligament (LDL)

Note: these two divide the joint mediolaterally in the superior and inferior joint cavities.

Question 19

What is the role of the capsular ligament?

Answer 19

Surrounds and encompasses the temporal mandibular joint.

Attach: superiorly to temporal bone @ mandibular fossa and articular eminenece, @ neck of the condyle.

Resists medial, lateral, or inferior forces that serparate or dislocate the articular surfaces.

Also, retaines synovial fluid.

Note: well innervated, so provides proprioceptive feedback for the joint

Question 20

What is the role of the temporomandibular ligament?

Answer 20

Composed of 2 parts:

outer oblique portion- from articular tubercle & zygomatic process to condylar neck

inner horizontal portion - from articular tubercle & zygomatic process to lateral pole of the condyle & articular disk Protects the retrodiscal tissues from trauma created by the posterior displacement of the condyle, and protects the lateral pterygoid muscle from over-extension.

Question 21

How far can the mouth separate before the condyles move from the fossae?

Answer 21

20-25 mm

Question 22

Which ligament forces the condyle to move downward and forward out of the fossa as it is opened past 25mm?

Answer 22

The outer portion of the temporomandibular ligament.

Question 23

Accessory ligament: what is the role of the sphenomandibular ligament?

Answer 23

No significant limiting effects on mandibular movement. From the spine of hte sphenoid bone and extends down toward to the lingula on the mandible.

Question 24

Accessory ligament: what is the role of the stylomandibular ligament?

Answer 24

Becomes taught when mandible is protruded, but relazed when mandible is opened. So, it limits excessive protrusive movements of mandible. Attaches to styloid process and extends to the angle and ramus of the mandible.

Question 25

Describe the anatomy of the articular disk:

Answer 25

Composed of dense fibrous connective tissue WITHOUT blood vessel and nerve fibers.

Question 26

What are the 3 zones of the articular disk (from sagittal view)?

Answer 26

1. Anterior portion. Thick area attached to the superior pole of the laeral pterygoid muscle.
2. Intermediate. Thinnest area.
3. Posterior. Thick area attached to loose connective tissue that is highly vascularized and innervated.

Question 27

Horizontal view of the TMJ: how are the condyles angled?

Answer 27

If an imaginary line were drawn through lateral and medail poles, would extend medially and posteriorly toward the foramen magnum.