Midterm Flashcards
Name the vascular supply of the TMJ:
- Superficial temporal artery (transverse facial)
- Maxillary artery (deep auricular masseteric & posterior deep temporal)
Name the nerve supply of the TMJ:
- Auriculotemporal (V3)
- Masseteric
What kind of joint is the TMJ?
Ginglymoarthridal
(Ginglymoid: rotational)
(Arthrodial: translational)
What is the difference between the TMJ and knee joint?
The articular surfaces of the TMJ are covered by fibrocartilage, but the articular surfaces of the knee are covered by hyaline cartilage.
Both have a meniscus/disk and synovial fluid
Synovial fluid in the TMJ capsule is secreted where?
The 1cc of synovial fluid in the TMJ is secreted by the membrane lining the joint
What is the function of the synovial fluid in the TMJ capsule?
- Lubricate joint
- Transports nutrients & waste
Describe the posterior attachment of the articular disk:
- allows a stretch of 2mm for forward translation of the mandible (moving the superior and inferior lateral pterygoid)
- highly vascularized (venous plexus) and innervated by the auriculotemporal nerve
Describe the intermediate zone of the articular disc:
Devoid of nerves or blood vessels. Articular with the superior aspect of the condyle during translation
What is the function of extracapsular ligaments like the sphenomandibular and stylomandibular ligaments:
Limits joint movement and stabilizes the mandible, prevents open lock
When the articular disc slips out of position, 95% of the time where is it?
anterior and medial
Does TMJ translation translation occur in the superior or inferior joint space?
What about rotation?
Translation = superior joint space
Rotation = inferior joint space
What are the three muscles of mastication that elevate/close the mandible:
- masseter
- medial pterygoid
- temporalis
What are the two muscles of mastication that allow for opening and lateral movements of the mandible?
- lateral pterygoid
- digastric
What is the insertion and function of the superficial masseter?
insertion = lateral ramus and angle of mandible
function = elevates the mandible
What muscle is responsible for elevating the mandible?
Superficial masseter
What is the attachment and function of the lateral pterygoid?
insertion = attaches to the articular disc and condyle
function = superior division pulls disc forward and assists in closing jaw (holds disc on condyle
function = inferior division protrudes and depresses the mandible, deviates jaw to the OPPOSITE side
What does treatment of TMD involve?
- orthopedic appliances
- behavior therapy
- TMJ surgery
What causes trauma to TMJ and masticatory muscles?
Grinding or clenching teeth
(dental procedures, sports injuries, motor vehicle accidents)
When screening for TMD what questions should you ask the patient if they experience?
- difficulty and/or pain with opening
- jaw locking/sticking/jaw going out of joint
- pain with chewing/talking/using jaw
- jaw joint noises
- stiffness/tiredness/tightness in jaw
- pain in or near the ears/temples/cheeks
- frequent headaches/neck aches/toothaches
- recent changes in bite
- recent injury to jaw/neck/head
- past treatment for facial pain or a jaw joint problem
What is the normal ROM for opening and lateral motions:
Normal opening= 40-60mm
Lateral motion= 9-12mm
What is the difference between disc displacement with and without reduction?
Disc displacement WITH reduction: mandible shifts to the side of the disc interference, then returns to a centered position at maximum opening after disc reduction occurs
Disc displacement WITHOUT reduction: mandible is continuously displaced and does NOT return to center; limited opening
In a muscle palpation exam, how is pain related and what does it mean if the pain spreads out?
0 (no pain)
3 (severe pain)
Referred pain/myofacial pain; document where that patient points the pain is spreading to
What should you palpate in an extraoral exam for TMD?
Temporalis and superior masseter
What should you palpate for an intraoral exam for TMD?
Medial and lateral pterygoid & temporalis tendon
What intraoral evidence of parafunction might you see?
- linea alba
- scalloped tongue
- attrition
Cranial nerve function test includes:
- olfactory
- optic
- ocular motor
- trochlear
- trigeminal
- abducens
- facial
- vestibulocochlear
- glossopharyngeal
- vagus
- accessory
- hypoglossal
- olfactory- test smell with cinnamon or vanilla
- optic- test vision one eye at a time
- ocular motor- reactive to light/ptosis
- trochlear- check for lateral gaze movement
- trigeminal- sensory: q-tip for non-noxious and needle prick for noxious; motor: ask patient to clench & feel for symmetry
- abducens- nystagmus oscillations
- facial- frown, smile etc.
- vestibulocochlear- no example given
- glossopharyngeal- gag reflex
- vagus- look for elevated uvula and palate when saying AHHH
- accessory- hands on should, shrug and turn head side-to-side
- hypoglossal- does tongue protrude straight?
Imaging techniques for hard tissue:
- Pano
- CBCT
- MDCT
Imaging techniques for soft tissue:
- MRI
- Arthrography
- Ultrasound
Imaging techniques for metabolic activity:
- nuclear medicine
- PET-CT
The lateral aspect of the condyle is best shown in what view for 2D radiography?
Transcranial
Advantages/Disadvantages of CBCT for evaluation of TMJ:
Advantage- lower dose than MDCT & CT
Disadvantage- does NOT show soft tissue, so cannot visualize location of disk
Advantage/Disadvantage of MRI for evaluation of TMJ:
Advantage- no ionizing radiation, best soft tissue imaging
Disadvantage- cost, 15-25% false positive finding of disc perforation. No greater accuracy for detecting disc displacement without reduction
Contraindication: implantable cardiac pacemaker
What is a contraindication of MRI for evaluation of TMJ?
Implantable cardiac pacemaker
How is arthrography used for TMJ? Advantages/Disadvantages:
Dye/contrast medium is injected into synovial space. Used to detect perforations/tears in articular disc (as seen in osteoarthritis)
Advantage: indicated prior to joint lavage
Disadvantage: ionizing radiation, invasive, unconfortable
How is nuclear medicine used for TMJ?
Radio-isotope like Gallium is injected into patients veins. Gamma camera takes images where radio-isotope has collected in areas of rapid bone turnover (10% increase of osteoblastic activity)
Disadvantage: expensive, invasive and not specific to any one disease
What is a PET-CT?
Combination of nuclear medicine and MDCT
Disadvantage: Higher dose and cost
What is aplasia?
-faulty/incomplete development of cranial bones or mandible
-congenital
-rare
-usually effects ear
What is hypoplasia? Examples?
Congenital or acquired under-development of cranial bones or mandible. Growth is normal is normal, but proportionally reduced.
Examples:
1. Treacher-Collins syndrome
2. Mandibular hypoplasia (congenital)
3. Condylar hypoplasia (contenital or acquired “trauma”)
What is hyperplasia? Examples?
Congenital or acquired over-development due to increase in the number of normal cells.
Examples:
1. Condylar hyperplasia
2. Mandibular hyperplasia (tx: osteotomy)
3. Coronoid hyperplasia
What is neoplasia? What imagine is best to see this? Examples? How can we discern benign from malignant?
Uncontrolled growth of ABNORMAL tissue
Imaging: nuclear medicine
Examples:
1. fibrous dysplasia
2. osteochondroma
Benign vs. malignant:
Examine the cortical outline of mandible to discern benign from malignant. Malignant destroys the bony margin, but benign does NOT.
What is subluxation?
Subluxation: the partial condylar dislocation during wide mouth opening but the patient can close voluntarily with a pop/click
-condyle is ANTERIOR to eminence
-caused by anatomy, habit, trauma
What is
