Midterm Flashcards
Name the vascular supply of the TMJ:
- Superficial temporal artery (transverse facial)
- Maxillary artery (deep auricular masseteric and 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/disc, and synovial fluid
Synovial fluid in the TMJ capsule is secreted from 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
- Transport nutrients and waste
Describe the posterior attachment of the articular disc:
- 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 ariculotemporal nerve)
Describe the intermediate zone of the articular disc:
Devoid of nerves or blood vessels. Articulates with there superior aspect of the condole 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 disk slips out of positions, 95% of the time where is it?
anterior and medial
Does TMJ translation occur in the superior or inferior joint space?
What about rotation?
Translation = superior joint space
Rotation = inferior joint space
What are the 3 muscles of mastication that elevate/ close the mandible?
- masseter
- medial pterygoid
- temporalis
What are the 2 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 the jaw (holds dic on condyle)
function = inferior division protrudes and depresses the mandible, deviates jaw to the OPPOSITE side
What does treatment of TMD involve?
- Orthopedic appliances
- Behavioral 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 or pain with pain with mouth opening
- jaw locking/sticking/jaw going out of joint
- pain with chewing, talking, or using jaw
- jaw joint noises
- stiffness, tightness, or tiredness in the jaw
- pain in or near the ears/ temple / cheeks
- frequent headeaches/ neck aches or tooth aches
- recent changes in bite
- recent injury to the jaw neck or head
- past treatment for facial pain or a jaw joint problem
What is the normal ROM for opening and lateral motions?
normal opening = 40-60 mm
lateral motion = 9-12 mm
What is the difference between disc displacement with and without reduction?
Disc displacement WITH reduction = mandible shifts to the side of the dic interference, then returns to a centered position, at maximum opening after dic reduction occurs
Disc displacement WITHOUT reduction = the 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 the patient points that pain is spreading to.
What should you palpate in an extra oral exam for TMD?
temporalis and superior masseter
What should you palpate in an intraoral exam for TMD?
medial & lateral pterygoid and temporalis tendon
What intraoral evidence of parafunction might you see?
- linea alba
- scalloped tongue
- attrition
Cranial nerve function test:
1. olfactory -
2. optic -
3. ocular motor -
4. trochear -
5. trigeminal
6. abducens
7. facial
8. vestibulochochear
9. glossopharyngeal
10. vagus
11. accessory
12. hypoglossal
- olfactory - test smell with cinnamon or vanilla
- optic - test vision one eye at a time
- ocular motor - reactive to light, ptosis
- trochear - check for lateral gaze movement
- trigeminal -
sensory: q-tip for non-noxious and needle prick for noxious
motor: ask patient to clench and feel for symmetry
- abducens- nystagmus oscillations
- facial- frown, smile, etc.
- vestibulochochear- no example given
- glossopharyngeal- gag reflex
- vagus- look for elevated uvula in palate when saying “ahh”
- accessory- hands on shoulders and shrug, turn head side to side
- hypoglossal - does tongue protrude straight?
Imaging techniques for hard tissue:
- Pano
- CBCT
- MDCT
Imaging techniques for soft tissue:
- MRI
- Arhtrography
- 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:
Advantages= lower dose than MD CT and CT
Disadvantage= does NOT show soft tissue, so cannot visualize location of disc
Advantage/ Disadvantage of MRI for evaluation of TMJ? Contraindication?
ADV: No ionizing radiation, best soft tissue imaging
DIS: Cost, 15-25% false positive finding of disc perforation, No greater accuracy for detecting disc displacement without reduction.
CONTRA: 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),
ADV: indicated prior to joint lavage
DIS: Ionizing radiation, invasive, uncomfortable
How is nuclear medicine used for TMJ?
Radioisotope like gallium is injected into patients veins. Gamma camera takes images where radioisotope has collected in areas of rapid bone turnover (10% increase of osteoblastic activity)
DIS: Expensive, invasive and not specific to any ONE disease
What is a PET-CT?
Combination of nuclear medicine and MD-CT.
DIS: 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 underdeveloped cranial bones or mandible. Growth is normal but proportionally reduced.
Examples =
1. Treacher- collins syndrome
2. Mandiublar hypoplasia (congenital)
3. Condylar hypoplasia (congenital or acquired - trauma)
What is hyperplasia? Examples?
Congenital or acquired overdevelopment due to the increase in the number of normal cells.
Examples:
1. Condylar Hyperplasia
2. Mandibular Hyperplasia (tx osteotomy)
3. Coronoid hyperplasia
What is neoplasia? What imaging 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 is 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
