TMJ Flashcards
What type of joint is the TMJ
Ginglymoarthrodial joint.
The Superior compartment of the TMJ is involved in what type of movement?
Translational
Rotational movement of the Condyle involves which compartment of the TMJ?
Inferior Compartment
The mandibular condyle is formed by what type of bone formation?
Intramembranous Ossification.
Most common site of bleeding in surgical approach to the TMJ Capsule?
Retrodiscal Tissue
Describe the TMJ disc
Biconcave cross-sectional morphology.
Which ligament limits posterior movement of the condyle?
Temporomandibular Ligament
Which ligament limits excessive mouth opening?
Sphenomandibular ligament
What is the main innervation of the TMJ?
Auriculotemporal nerve
What is the Vascular Supply of the TMJ?
Anteiror: Superficial temporal and maxillary artery
Posterior: Masseteric artery
What muscles are primarily involved in opening the mouth
Lateral Pterygoid, Digastric
Which muscels are primarily involved in closing the mouth?
Masseter, Temporalis, Medial Pterygoid
Which muscle(s) are primarily involved in protrusion of the mandible?
Anterior head of Temporalis
Which muscle(s) are primarily involved in retrusion of the mandible?
Posterior head of Temporalis
Name the Facial Layers to Access TMJ Capsule?
Skin,
SubQ,
SMAS/TP fascia,
Superficial layer of deep Temporalis fascia, Periosteum of zygomatic arch/ lateral capsule.
Which layer is the Temporal branch of the Facial nerve?
Deep to TP fascia/SMAS
What is the mean distance between the anterior border of the bony external auditory canal and the temporal branch of the Facial nerve?
0.8 to 3.5cm (Al-Kayat Study)
How do you control excessive bleeding encountered when entering the TMJ joint space?
Most likely source is Retrodiscal tissues. Control bleending in by reseating the condyle in the fossa and maintaining pressure for several minutes. Or by using electrocautery.
MRI T1 bright signal?
Fat
MRI T2 bright signal?
Water
Gallium-67 is best used for?
Osteomyelitis
Technetium-99 is best used for?
Bone remodeling/ Growth activity
Normal position of the disc on MRI closed mouth view?
Posterior band of disc at 11-12 o’clock position
Normal position of the disc on MRI in open mouth view?
Intermediate zone interposed between condyle and articular eminence. Remains biconcave.
When do you use a repositioning splint?
In patients when anterior mandibular positioning can recapture an anteriorly displaced disc.
*Must be monitored carefully to prevent shifting of the dentition.
Osteoarthritis is an Inflammatory arthritis or Noninflammatory arthritis?
Noninflammatory
Contrast Osteoarthritis and Rheumatoid arthritis.
Osteoarthritis= Noninflammatory.
Occurs Later in life- slow progression.
No swelling.
Single Joint
Morning stiffness < 1hr.
No Systemic Effects.
Rheumatoid arthritis
Rapid onset. Any time in life.
50% involve TMJ
Painful + Swollen
Symmetric/ Multiple joints
>1hr Morning stiffness
Systemic effects present.
8yr Female with “bird face deformity” (Loss of height with class 2 malocclusion and apertognathia. What labs do you order?
Juvenile RA.
Rheumatoid factor. ANA. ESR.
Ankylosing Spondylitis is more prominent in Males or Females?
Males
How many patients with psoriasis will also have arthritis?
One third of patients
What is the clinical triad of Psoriatic arthritis?
Psoriasis
Radiographic evidence of erosive arthritis
Negative serology for RF.
What serology will be positive for Ankylosing spondylitis?
HLA-B27 antigen
RF will be negative.
What is the clinical triad of Reiter Syndrome
Uveitis (can’t see)
Urethritis (can’t pee
Arthritis (can’t climb a tree)
What causes Reiter syndrome?
Intestinal infection (Salmonella, Shigella)
Sexually transmitted infection (Chlamydia, Gonorrhea)
3yr old boy presents with fever, rash, joint pain and swelling, and hepatosplenomegaly.
Still Disease.
Subtype of JRA. Boys <5yrs
Seronegative for RF, ANA.
Monosodium urate monohydrate crystals=
Gout
Calcium pyrophosphate dehydrate crystals=
Pseudogout
Patient presents with Trismus, Deviation on opening, preauricular pain and swelling, pain in first metatarsophalangeal joint. Joint fluid aspirate shows needle shaped crystals with negative birefringence to polarized light microscopy.
gout
What is the Etiology of Gout vs Pseudogout?
Overproduction or underexretion of uric acid = Gout
Abnormally high concentration of inorganic pyrophosphate in synovial fluid= pseudogout.
Risk factors for gout?
Purine-rich diet
Diuretics
Excessive alcohol
Males> Females
40+
Polarized light microscopy showing rhomboid shaped crystals with weakly positive birefringence.
Pseudogout.
Treatment for Gout
Purine-low diet
Colchicine
Urate-lowering drugs (xanthine oxidase inhibitors, uricosuric drugs)
