2/14: Mechanics of Mandibular Movement Flashcards
What are the 4 anatomic determinants of anatomic movement?
- Right TMJ
- Left TMJ
- Teeth/occlusion
- Neuromusculature
What are the two types of movements within the TMJ?
- Rotational movement
- Translation movement
Where does rotational movement occur?
In the inferior joint compartment
Where does translation movement occur?
In the superior joint compartment
What is rotation?
Process of turning about an axis
When does rotation occur?
When the mouth opens and closes around a fixed point or axis within the condyles
What compartment does rotation occur within?
The inferior joint compartment
How do the condyles move during rotation?
Condyle rotates on the inferior aspect of the articular disk
Rotation occurs for the first ________mm of opening
20-25
What occurs when it further opens?
Translation occurs
What planes can rotational movements occur?
In all three reference planes in the mandible
1. Rotation in the Sagittal plane around a horizontal axis
2. Rotation in the Horizontal plane around a vertical (frontal) axis
3. Rotation in the Frontal plane around a sagittal axis
What is the rotation like around a horizontal center with a sagittal plane?
What is the rotation like around a vertical center of rotation with a horizontal plane?
What is the rotation like around a sagittal center of rotation with a vertical plane?
What is the horizontal axis that passes through both R and L condyles called?
– Terminal hinge axis
– Transverse hinge axis
– Horizontal hinge axis
What movement is clinically identifiable and recordable?
Rotation in the sagittal plane around a horizontal axis
What is the only rotational movement that can be isolated clincially?
Rotation in the sagittal plane around a horizontal axis
When does Rotation in the sagittal plane around a horizontal axis only occur?
When the mandible is in CR
What is frontal axis of rotation?
Rotation in the horizontal plane around a frontal (vertical) axis