TMJ Disorders

Question 1

What type of joint is the TMJand what are the components?

Answer 1

• Hinge (arthroidal)
• sliding (ginglymo)
• Components: condyle, glenoid fossa (Squamous temporal bone), articular disk, joint capsule, extrinsic and intrinsic ligaments

Question 2

Describe jaw movmeent and disc mechanics

Answer 2

• with small mouth opeing, hinge motion allows condyle to rotate on disc
• with wide mouth opening, sliding motion necessary to allow condyle to slide forward along disk and stops at articular eminence
• Articular disk is responsible for bidirectional motion

Question 3

What muscles act on the TMJ?

Answer 3

• Proper
  
  • Masseter - closure
  • Temporalis - closure and retrusion
  • Medial pterygoid - closure and protrusion
  • Lateral pterygoid
    
    • superior (insert onto disk)- closure, retrusion
    • inferior (insert onto condyle) - opening and protrusion
• Complementary
  
  • digastric - opening
  • Geniohyoid - opening
  • infrahyroid - fixation of hyoid

Question 4

What are the extrinsic ligaments of the TMj

Answer 4

• stylomanidbular
• sphenomandibular
• lateral temporomanidbular
• pterygomandibular

Question 5

How do you clasify TJ Disorders

Answer 5

• Muscle-realted = Myogenous
• Joint-related = arthrogenous
  
  • DDD = disk displacement disorder
  • DJD = dgenertive joint disease
  • systemic arthritis
  • recurrent dislocaiton
  • infection
  • ankylosis

Question 6

What is centric relation and central occlusion

Answer 6

• C. relation - positon of TMJ with condyle in most retruded and non -restraied position in the glenoid fossa
• C. occlusion - position of mandible with maxillary and mandibular teeth in maximal intercuspation

Question 7

What happens with the disk during joint opening and closure

Answer 7

Closure ->superior lat pterygoid attached to anterior disk, stabilizes disk during closure

Question 8

Whta is normal interincisal opening and normal protrusion.lateral displacement

Answer 8

40-50mm

10mm

Question 9

What is your management of a ptient presenting with TMJ pain

Answer 9

HISTORY

• Clasic triad
  
  • Pain: if muscle - better with motion, if joint - worse w activity
  • Limited ROM
  • Clicking/crepitus
  • clicking in am - nocturnal bruxism
  • clicking w pain - internal derangement
  • crpitus - disk perforation/calcification, meniscal tear

PHYSICAL EXAM

• ROM
• OCclusion
• cliking/crepitus, tenderness of TMJ
• masticatory musculature hypertrophy
• head posture, general H&N, including CN7 fx

Investigation

• ESR, CRP, RF, ANA, uric acid
  *

Question 10

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