Anatomy of the Temporomandibular Joint

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Questions and Answers

What bones are involved in the articulation at the temporomandibular joint?

One temporal bone and one zygomatic bone

Two occipital bones and two maxillae

Two nasal bones and two sphenoid bones

Two temporal bones and two mandibular condyles (correct)

Which part of the temporal bone articulates with the mandible at the TMJ?

Squamous part

Mandibular fossa (correct)

Zygomatic process

Mastoid process

What role does the disc of the joint play in the TMJ?

It permits the surface of one bone to move over another (correct)

It creates a barrier against injury

It increases the range of motion of the joint

It strengthens the bones around the joint

Where is the postglenoid process located in relation to the articular fossa?

Posterior to the articular fossa (A) Signup and view all the answers

Which part of the mandible is specifically involved in the articulation at the TMJ?

Mandibular condyle (C) Signup and view all the answers

What is the role of the sphenomandibular ligament during mandibular movement?

It prevents the diffusion of local anesthetic during an inferior alveolar nerve block. (D) Signup and view all the answers

Which movements are associated with the TMJ during the opening of the mouth?

Only protrusion and depression occur. (A), Both rotational and gliding movements occur. (B) Signup and view all the answers

Which of the following movements is NOT a function of the TMJ?

Circumduction (B) Signup and view all the answers

What describes the function of the sphenomandibular ligament in clinical dental procedures?

It is a landmark for administering local anesthetics. (A) Signup and view all the answers

What best describes TMD (temporomandibular disorder)?

It is a pathology associated with one or both TMJs. (A) Signup and view all the answers

What is the primary function of the articular disc in the TMJ?

To completely divide the TMJ into two compartments (A) Signup and view all the answers

Which ligament is NOT associated with the temporomandibular joint?

Cervical ligament (A) Signup and view all the answers

What is the role of synovial fluid in the TMJ?

To lubricate the joint and facilitate smooth movement (D) Signup and view all the answers

Where is the articular eminence located in relation to the mandibular fossa?

Anterior to the mandibular fossa (B) Signup and view all the answers

What tissue composes the retrodiscal pad of the TMJ?

Loose connective tissue (D) Signup and view all the answers

What is the main function of the temporomandibular ligament?

To prevent displacement of the condyle (A) Signup and view all the answers

The stylomandibular ligament connects which two structures?

The styloid process of the temporal bone and the angle of the mandible (A) Signup and view all the answers

What structure lines the cavities of the TMJ and secretes synovial fluid?

Joint capsule membranes (D) Signup and view all the answers

What are common symptoms associated with temporomandibular disorders (TMD)?

Chronic joint tenderness (A) Signup and view all the answers

During a TMJ assessment, which motion is NOT typically evaluated?

Nodding the head (B) Signup and view all the answers

What is the primary origin of symptoms in clients with TMD?

Muscles supporting the joint (D) Signup and view all the answers

What might cause TMJ sounds during jaw movement?

Disc disengagement (A) Signup and view all the answers

What condition describes the inability to open the mouth normally?

Trismus (D) Signup and view all the answers

What treatment is commonly suggested for managing bruxism?

Night guard (C) Signup and view all the answers

What leads to an acute episode of TMD when opening the mouth too wide?

Subluxation (C) Signup and view all the answers

In myofascial pain dysfunction (MPD), what is primarily responsible for increased pain at the TMJ?

Psychological stress (C) Signup and view all the answers

What is a potential consequence of constant anterior displacement of the TMJ disc?

Permanent joint damage (C) Signup and view all the answers

Which of the following treatments is NOT usually recommended for TMD?

Frequent surgical interventions (B) Signup and view all the answers

Study Notes

Temporomandibular Joint (TMJ)

The TMJ is a joint on each side of the head that allows for movement of the mandible for speech and mastication.
The TMJ is the articulation between the temporal bone and the mandible.

Bones of the Joint

The temporal bone is a cranial bone.
The mandibular fossa or articular fossa is an oval-shaped depression on the temporal bone.
The mandibular condyle is the articulating part of the mandibular ramus.
The mandible is a facial bone.

Joint Capsule

A fibrous joint capsule completely encloses the TMJ.
The joint is supported by the joint capsule and several ligaments.

Disc of Joint or Articular Disc

The articular disc is a fibrous pad of collagen tissue located between the temporal bone and the mandible.
The disc completely divides the TMJ into two compartments: upper and lower.
The synovial cavities are lined with epithelium, which secretes synovial fluid.

Structure

The articular eminence is a smooth, rounded ridge positioned anterior to the mandibular fossa.
The retrodiscal pad is composed of loose connective tissue supplying blood and nerves to the joint.

Ligaments Associated with the Joint

Three paired ligaments are associated with the TMJ:
- Temporomandibular ligament
- Stylomandibular ligament
- Sphenomandibular ligament

Temporomandibular Ligament

Reinforces the lateral part of the joint capsule.
Prevents the condyle from being displaced too far inferiorly and posteriorly.
Prevents lateral displacement of the mandible.

Stylomandibular Ligament

Runs from the styloid process of the temporal bone to the angle of the mandible.
Separates the parotid and submandibular salivary glands.

Sphenomandibular Ligament

Is not considered part of the TMJ.
Helps control movement.
Runs from the angular spine of the sphenoid to the lingual.
Becomes taut when the mandible protrudes.
May prevent diffusion of local anesthetic agents during an IA nerve block.

Movement in the TMJ

The TMJ has two types of movement:
- Rotational - occurs in the lower synovial cavity between the disc and the condyle.
- Gliding - occurs as the jaw opens farther.

Gliding Movement

Protrusion - anterior movement.
Retrusion - posterior movement.

Rotational Movement

Depression - lower the jaw.
Elevation - raise the jaw.

Gliding and Rotational Movement

Lateral Deviation - alternating protrusion and retrusion.
Opening the mouth - protrusion and depression.
Closing the mouth - retrusion and elevation.

TMJ Dysfunction (TMD)

TMD may involve one or both TMJs.
Symptoms include: chronic joint tenderness, swelling, painful muscle spasms, limited or deviated mandibular opening.

Assessing the TMJ for TMD

Palpate the joint and its associated muscles bilaterally, just anterior to the external acoustic meatus of each ear.
Ask the client to open and close the mouth, move the opened jaw left and right, and forward.

TMD

Not all clients with TMD have abnormalities in the joint disc or the joint itself.
Most symptoms originate from the muscles supporting the joint.

TMJ Sounds

Clicking, popping, or grinding (crepitus) in the TMJ.
Popping or clicking occurs when the disc is pulled too far forward on opening.
If it pops on closing, it is called a "reciprocal pop or click."
On palpation, the joint may "jump."
The mandible may deviate/shift to one side on opening.

Disc Disengagement

The cause of TMJ sounds may be the result of disc disengagement.
In constant anterior displacement of the disc, permanent damage may occur.
Treatment may require surgical intervention.

Trismus

Inability to open the mouth normally.

TMJ Problem: Subluxation

An acute episode of TMD can occur when the mouth opens too wide.
The condyle glides too far forward and moves too far anterior to the height of the articular eminence.
Contributing factors: deep condylar fossa, hypermobility, and muscle incoordination.

TMJ Problem: Bruxism

Teeth grinding, typically during sleep, but some do it while awake.
Causes tired and sore TMJ, wearing down of teeth.
Treatment: night guard, relaxation medications.

TMJ Problem: Arthritis

Inflammation and deterioration of the joint.
Potentially caused by excessive wear of the joint.
Treatment option: cortisone.

TMJ Problem: Myofascial Pain Dysfunction (MPD)

Increased pain at the TMJ due to muscle tension and spasm.
Believed to be a physical manifestation of psychological stress.
No primary disorder of the joint itself is present.

TMD

Most cases of TMD improve over time with conservative treatments, including pain control, relaxation therapy, stress management, habit control, moderate muscle exercises, and orofacial myology.

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Description

This quiz explores the anatomy and functions of the temporomandibular joint (TMJ). It covers related bones, joint structure, and the function of the articular disc within the TMJ. Test your knowledge on this crucial component of oral anatomy and its role in movement.