Temporomandibular Joint-Lecture

Question 1

Muscles opening the mouth (depresion of mandible)

Answer 1

1. Latera (external) pterygoid -mandibular (CN V)

Question 2

Muscles closing the mouth (elevation of mandible or occlusion)

Answer 2

1. Masseter -Mandibular nerve (CN V)
2. Temporalis -(CN V)
3. Medial (internal) pterygoid -(CN V)

Question 3

Muscles for protrusion of mandible

Answer 3

1. Lateral (external) pterygoid -Mandibular nerve (CN V)
2. Medial (internal) pterygoid -Mandibular nerve (CN V)

Question 4

Muscles for retraction of mandible

Answer 4

1. Temporalis (posterior fibers) -Mandibula nerve (CN V)

Question 5

Muscles for lateral devation of mandible

Answer 5

1. Lateral (external) ptreygoid ((ipsilateral muscle))
2. Medial (internal) pterygoid ((contralateral muscle))

both mandibular nerve (CN V)

Question 6

Why is TMJ important?

Answer 6

• Without these joints we would severely be hindered in talking, yawning, eating, kissing, or sucking
• TMD is the second most commonly occurring musculoskeletal condition resulting in pain and disability (after chronic low back pain)
• Affects approx. 5-12% of the population
• Annual cost estimated at $4 billion

Question 7

TMJ joint- type

Answer 7

• modified hinge joint

Question 8

TMJ joint- articulation

Answer 8

1. condyle of the mandible
2. articular tubercle & mandibular fossa

Question 9

TMJ joint- capsule

Answer 9

• attaches to margins of articular area on temporal bone and around neck of mandible

Question 10

TMJ joint- features

Answer 10

1. articular surfaces covered by fibrocartilage
2. articular disc divides jt space into two compartments (two synovial membranes)

Question 11

TMJ lower compartment

Answer 11

• hinge-like movement (depression and elevation of the mandible)

Question 12

TMJ upper compartment

Answer 12

• forward (protrusion) and backward (retraction) movements of mandible –translation

Question 13

TMJ rotation movement

Answer 13

• Rotation occurs from the beginning to the midrange of movement
  
  • Upper head of lateral pterygoid muscle draws the disc anterior to prepare for condylar rotation during movement
  • Movement occurs between two condylar heads with disc in between
    
    • **Importance of disc is to provide congruent contours and lubrication of joint

Question 14

TMJ translation movement

Answer 14

• Translation or gliding occurs during second half of range (Depression)
  
  • Condyle and disc along the slope of the articular eminence

Question 15

Additional anatomy

Answer 15

• As the mandible moves forward on opening, the disc moves medially and posteriorly until the collateral ligaments and lateral pterygoid stop its movement. (Seating of disc)
  
  • If seating does not occur, full ROM is limited
• lInnervation: Branches of the auriculotemporal and massenteric branches of the mandibular nerve

Question 16

Ligaments

Answer 16

1. Temporomandibular / Lateral
2. Sphenomandibular
3. Stylomandibular

Question 17

TMJ- resting position, close packed, and capsular pattern

Answer 17

• resting position- Mouth slightly open, lips together, teeth not in contact
• close packed- Teeth tightly clenched
• capsular pattern- Limitation of mouth opening

Question 18

Muscles of mastication- Temporalis

Answer 18

• Action: Elevation and retraction of mandible
• Origin: Bone of temporal fossa and temporal fascia
• Insertion: Coronoid process of mandible and anterior margin of ramus of mandible

Question 19

Muscles of mastication- Medial Pterygoid

Answer 19

• Action: Elevation and side to side movement of mandible
• Origin: Medial surface of lateral plate of pterygoid process and tuberosity and pyramidal process of maxilla
• Insertion: Medial surface of mandible near angle

Question 20

Muscles of mastication- Lateral Pterygoid

Answer 20

• Action: Protrusion and side to side movements of mandible
• Origin: Roof of infratemporal fossa and lateral surface of lateral plate of pterygoid process
• Insertion: Capsule of TMJ in region of attachment to the disc and to the pterygoid fovea on the neck of mandible

Question 21

Muscles of mastication- Masseter

Answer 21

• Action: Elevation of mandible
• Origin: Zygomatic arch and maxillary process of the zygomatic bone
• Insertion: Lateral surface of ramus of mandible
• *Deep and superficial parts

Question 22

Temporomandibular disorder

Answer 22

• TMD is the general diagnosis given for any and all issues associated with the jaw
  
  • Athritis
  • Internal Derangement
  • Trauma
  • Pain Dysfunction Syndrome / Myofascial Pain
• **Most insurances especially Medicare will not cover physical therapy if the diagnosis is TMD.**
  
  • Educate physicians / dentists to include diagnosis as myositis and myalgia
• Normal age range affected is 20 y/o to 40 y/o
• TMD affects females 2:1 versus males
• Poor posturing of the neck is the main reason for issues with TMJ.

Question 23

common s/s

Answer 23

• Headaches / Migraines
• Popping or clicking
• Ear pain / Jaw pain
• Loss of hearing
• Pressure in the eyes
• Muscle spasms around jaw
• Tenderness or swelling in face
• Locking open or closed
• Ringing in the ears
• Blurred Vision
• Toothaches that cannot be traced to decay, nerve death or inflammation
• Burning or tingling sensations in tongue
• Hoarseness or Laryngitis
• Limited opening of jaw

Question 24

Contributing factors to TMD

Answer 24

• Incorrect chewing
• Malocclusion of teeth
• Premature loss of teeth
• Poor oral habits: chewing on gum, nails, pen/pencil, cheek
• Open mouth breathing
• Grinding / clenching of teeth
• Poor Posture
• Caffeine
• Vitamin Insufficiency
• Braces
• Scoliosis
• Forceps Delivery
• Rheumatoid Arthritis
• Allergies
• Tonsil/Adenoid disorders