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29 Cards in this Set
- Front
- Back
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1. What is the temperomandibular joint?
What does it provide for? Therefore, what is another name for it? |
Area where the mandibular condyle articulates at the base of the cranium w/ the squamous portion of the temporal bone
Provides for hinging movement in one plane (ginglymoid joint) and at the same time provides for gliding movements (arthroidal joint) Ginglymoarthroidal joint |
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2. From the anterior view, how does the condyle appear?
Which one is more prominent? |
Has 2 projections:
-medial pole -lateral pole Medial pole (extends well beyond the neck of the condyle) |
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3. From which view of the condyle is the articular surface greater?
How do the condyles appear from the occlusal view? |
Posterior view
Not parallel to the transverse axis of rotation Instead they are directed medially and anteriorly from the axis |
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4. Where does the condyle fit into?
What is the articular eminence? |
Concave mandibular fossa (articular fossa, glenoid fossa)
Convex bony prominence anterior to the mandibular foss |
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5. What overlays the surface of the articular surface and articular eminence?
What is the articular zone? What is it composed of? What is special about the TMJ? |
Thick, avascular layer of fibrous connective tissue
Dense fibrous connective tissue Collagen and hydrophilic proteoglycans that bind interstitial fluid Only joint not covered by hyaline cartilage |
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6. What separates the condyle from the mandibular fossa?
How is the TMJ classified and why? |
Articular disc
Compound joint (requires 3 bones) -b/c the disc acts as a nonossified bone |
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7. What is the articular disc composed of?
How does it move? What is the intermediate zone? |
Dense fibrous CT
Moves w/ the head of the condyle in function Thinnest zone and has no blood supply |
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8. What is retrodiscal tissue?
What does it do? What is another name for it? |
Region of loos CT that is high vascularized and innervated that has elastic fibers
Attaches the disc posteriorly to the tympanic plate of bone and to the capsule Bilaminar zone |
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9. How is the articular disc attached anteriorly?
How does the disc compare medially and laterally? How does the disc attache to the lateral and medial borders of the condyle? |
Attached to the fibrous capsule superiorly and inferiorly and in between to the superior head of the later pterygoid muslce
Thicker medially than laterally Attached by discal ligaments |
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10. What are six functions of the articular disc?
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1. Partitioning of the TMJ into functional compartments
2. Stabilizing the condyle 3. Helps to lubricate the TMJ (smooth and slippery) 4. Shock absorption 5. Reducing physical wear and strain on joint surface 6. Helps to regulate movements of the condyle |
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11. What is the fibrous capsule?
What does the inner layer do? What does the outer layer do? |
Sheet, sac, or tube of tissue that encloses the TMJ like a tube
Secretes synovial fluid Thick fibrous tissue that protects the joint and helps to limit movement |
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12. Where does the temperomandibular ligament attach?
What does it do? |
Attaches to the zygomatic arch and lateral and posterior aspect of the condyle
Prevents posterior and lateral displacement |
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13. What does the stylomandibular ligament do?
What does the sphenomandibular ligament do? Overall, what do ligaments not do? |
Tenses when the mandible protrudes
Restricts opening of the mandible Do not actively participate in normal joint function |
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14. What aids the muscles of mastification?
What are the four muscles of mastification? |
Digastric muscles
The supra- and infra-hyoid muscles Muscles of neck and shoulder Masseter, temporalis, lateral pterygoid, and medial ptyergoid |
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15. What is the origin, insertion and function of the masseter muscle?
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O: zygomatic bone
I: angle of the mandible F: closes the jaw (i.e. elevates the mandible) |
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16. What is the origin, insertion, and function of the temporalis?
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O: temporal fossa
I: cornoid process of the mandible and anterior border of the ramus F: anterior fibers elevate the mandible; posterior fibers retrude the mandible |
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17. What is the origin, insertion, and function of the medial pterygoid muscle?
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O: medial surface of the lateral pterygoid plate of the sphenoid
I: medial angle of the mandible F: elevate the mandible |
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18. What is the origin, insertion and function of the lateral pterygoid (upper head) muscle?
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O: infratemporal surface of the great wing of the sphenoid bond
I: mainly into the articular disc, but also into the condyle F: symmetrical - opening/closing and protrusion asymmetrical - lateral movement of the mandible |
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19. What determines the positing of the articular disc?
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Balance between the elastic fibers of the retrodiscal tissue pulling back versus the superior lateral pterygoid muscle pulling forward
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20. What is the origin, insertion, and function of the lateral pterygoid (lower head) muscle?
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O: lateral side of lateral pterygoid plate of sphenoid
I: neck of condyle F: symmetrical - opening/closing and protrusion asymmetrical - lateral movement of the mandible |
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21. The TMJ is a compound joint whose structure and function is divided into what 2 distinct systems?
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1. Lower compartment
-condyle-disc -responsible for the rotational movement of the mandible 2. Upper compartment -condyle-disc complex functioning against the mandibular fossa and articular eminence |
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22. How does the condyle fit under the disc?
What does this allow for? |
Like a bonnet
Enables condyle to rotate under the disc b/c of its attachment to the disc by the discal ligaments medially and laterally |
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23. What is the upper compartment responsible for?
In what three planes can the mandible move? |
Translational movement of the mandible
Sagittal, frontal, and transverse |
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24. What is terminal hinge movement?
What is the limited to? |
Rotation w/ the condyles stabilized under the disks superiorly positioned in the fossae
About 25 mm |
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25. What is translation?
What is it approximately? What is complex movement? |
The disk condyle complex moves anteriorly in protrusion
10 mm Combines both rotation and translation in a single event (i.e. speech, chewing, swallowing) |
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26. At what three points do we record mandibular motion?
In most adults, how does a sliding tooth contact movement position the mandible? What is retruded contact? |
Incisor point, molar point, condylar point
Slightly posterior from MI to RCP Superior limit of the terminal hinge movement (used synonymously w/ centric relation and centric occlusion) |
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27. What is pure rotational opening?
What does the second stage of opeing involve? How is the condyle translated? |
Rotational movement of the mandible w/ the condyles in the terminal hinge position
Both rotation and translation Down the articular eminence (vertical condylar guidance) |
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28. From MI, as the mandible protrudes, what causes the posterior teeth to disarticulate?
What is horizontal movement considered to be? What does continued forward movement result in? |
Anterior guidance (gliding of lower anterior teeth over upper anterior teeth)
As the incisal edges of the maxillary and mandibular teeth pass across each other Superior movement as the anterior teeth pass beyond the end-to-end position *extend of continued forward movement is determined by ligament tension |
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29. On Posselt's diagram, where is the postural position located?
When is meant when we say a person is naturally in centric relation? |
2 to 4 mm below the IP or MI position
There is no slip from MI to RC so centric relation is optimal condylar position (RC = MI) |
