TMJ Flashcards
**What does TMJ stand for?
temporomandibular joint
**What is a joint?
The joining together of 2 bones - many possible types
**The TMJ is the articulation between what two bones?
Mandible and temporal bones
**What are the four skeletal formations of these bones connected with the TMJ?
- Condyle of the mandible
- articular eminence of temporal
- mandibular fossa (glenoid)
- posterior tubercle
***Describe the Articular Disc. What is another name for this disc?
Meniscus. Small fibrous pad of dense collagen tissue
- no blood supply or nerves at center but rich supply in posterior region
- thinnest at center
- much thicker at posterior area
Attached - above to temporal bone
- below to cirumference of condyle
- posterior to ramus
**What are the Synovial Cavities and what does the fluid in these cavities provide?
Sac-like compartments above and below the meniscus.
Cells of lining secrete lubricant for the joint.
Allows surfaces to rub together without irritation.
Also nutrients for cells of meniscus.
**What is the Articular Capsule? (Name is joint capsule in text) Is this the same as the TMJ ligament? Explain your answer.
It is different than ligament.
Ligament is lateral thickening of capsule.
It attaches between zygomatic arch and lateral pole of condyle.
Prevents extreme movements
A capsule is a sock like structure / connective tissue that surrounds the joint - attaches above and below.
**Describe what is meant by Subluxation:
Condyles slip forward to articular eminence (cant close the jaw)
**Describe what is meant by Bruxism:
Excess grinding - teeth to teeth habit causing abnormal wear - usually occurs at night.
May cause TMJ soreness. Over function of muscles.
**What are the two TMJ movements and when do they occur?
Hinge: rotation. lower synovial cavity and condyle upon opening
Gliding: joins rotational movement as teeth open further. Upper cavity - gliding of condyle along posterior of articular eminence.
**What is the cause of most TMJ pain?
Muscular pain is most likely.
Also could be reffered pain. Clenching/Bruxism
What type of joint is the TMJ?
Compound Ginglymodiarthrodial Joint
Compound: articular disc between 2 opposing bones of a joint
Ginglymo: joint with a hinge motion
Diarthroidial: has synovial fluid
What are the structures and landmarks associated with the TMJ?
Postglenoid process/tubercle Zygomatic process Articular eminence Articular fossa Condyle of mandible
What are the soft tissue structures between the bones of the TMJ?
Blood Vessels
Articular disc/ meniscus/ joint disc
Lower synovial cavity and upper
Lateral pterygoid muscle
What is Rheumatoid Arthritis?
it is the destruction of cartilage and synovial capsule, therefore lacks nourishment to disc and bone; entire joint becomes involved
What is the TMJ ligament?
- It acts as the main suspensory ligament of the mandible during moderate opening movements
- prevents excessive retraction/moving back of the mandible
- Attachment from zygomatic arch and to posterior neck of condyle
What is the Sphenomandibular ligament?
- Acts as a suspensory ligament
- Attached from spine of sphenoid bone to the lingula
What is the stylomandibular ligament?
- It acts as a check-rein on the mandible and helps to prevent excessive anterior drift at the angle during the more extreme opening movements
- Attaches from styloid process to the angle of the mandible (posterior/medial surface)
What is the Lateral pterygoid muscle (aka external pterygoid)?
As this muscle contracts forward movement occurs of both the disc and the condyle
What is the movement of the TMJ at rest?
- Jaw is relaxed and teeth are separated slightly “ space is called the Freeway Space”
- The condyles rest slightly on the posterior slope of the circular eminence
What is the movement of the TMJ during Centric Occlusion? (CO)
- Teeth are in maximum intercuspation
- not a restful position
- condyles are in the mandibular fossa
- little or no upwards force
- requires muscular effort
What is the movement of the TMJ during Centric Relation? (CR)
- Jaw is retruded from CO usually 2-3mm
- This position requires muscular effort to maintain
- mandible is in the most posterior position
- condyles in the most upward position
- “moving jaw backwards”
What is protrusion?
- condyles move anteriorly and inferiorly along the posterior slope of the articular eminence. The disc and condyle move together
- mandibular moves anterior
What is retrusion?
- from centric occlusion, condyles and discs move upward and backward on the articular eminences to lie in the mandibular fossa
- movement of the mandible from CR (TMJ) or CO (teeth)
- mandible moves posterior
What is lateral excursion?
- basic side to side movements allow us to grind food
- mandible moves left / right
What is vertical movements?
- elevation and depression or closing and opening the mouth
- True hinge action
What is happening to the condyles during depression/elevation as a vertical movement?
What happens during the maximum opening of the condyles?
-initially they undergo a slight rotation in the lower compartment, then they move downward and forward along the eminence
maximum opening: condyles rest atop the articular eminences
Elevation: opposite of depression
-Opening and closing of jaw
What are some TMJ problems? (5)
- pain
- sounds
- subluxation
- bruxism
- arthritis
Why might someone have TMJ pain?
Stress, trauma, missing teeth
- diagnosed with assessment
- may be reffered pain (from neck)
Why would someone have sounds (popping/clicking) coming from TMJ movements?
- thick posterior band gets caught between condyle and eminence (pop/clicks)
- grinding sounds - possible degenerative / patho changes to structure
-diagnosed with assessment (feeling)
What happens to the condyle during subluxation?
it moves forward to articular eminence
*requires assistance to return to position
What is bruxism?
- action of grinding teeth
* at night it wears the teeth and increases muscle fatigue = painful
What type of arthritis can result from TMJ problems?
-rheumatoid/other = inflammatory changes in tissue
