Part 1 Flashcards
What are some none joint disorders that can refer pain to the TMJ?
- sinusitis
- lateral phyaryngeal space infection
- 3rd molar tooth abscess
- otitis
- parotitis
- herpes zoster
- visceral referred pain
- temproal arteritis
- meniere’s disease
What drugs can refer pain to the TMJ?
- citalopram (celexa)
- fluoxetine (prozac)
- paroxetine (paxil)
- sertraline (zoloft)
- amphetamines
- phenothiaxines
- ecstasy
The TMJ is innervated by what nerves?
- auriculotemporal of CN V
2. Masseteric of CN V
Where is the trigeminal nucleus located?
the Pons of the brainstem extending down to the medulla sharing the gray matter with C1-3
The trigeminal nucleus influences and is influenced by what other neural pathways?
- trigeminal CN V
- Facial nerve CN VII
- Vestibular CNVIII
- Glossopharyngeal nerve CN IX
- Vagus nerve CN
- dorsal roots of of C1-3
How does the forward head position effect the loading of the cervical joints?
line of gravity is moved posterior increasing loading on the posterior facets of the upper and mid cervical spine
Forward head position will contribute to what cartilage pathology and why?
- Degeneration of the cartilage
- the constant loading prevents the optimal stimulus of compression decompression with gliding for cartilage
- consequently the nutritional status of cartilage is compromised and degeneration can occur
What is unique about the DRG of the upper cervical spine?
the DRG can occupy up to 76% of the foremen height rendering vulnerable to entrapment particularly with extension
How does forward head effect the cervical flexors?
- places them at a mechanical disadvantage
- creates progressive weakness
- leads to facilitation of forward head position
How does the forward head position effect the position of the mandible?
The mandible goes into a class II or retrognathism occlusal pattern if compensations are not made
What compensations are made in the mandible to normalize occlusion with a forward head?
The masseter and pterygoids must pull the mandible forward for class I occlusion
How do the two head of the lateral pterygoid work in opposition to each other
- superior works eccentrically to reposition the disc the disc into optimal position between condyle and fossa during mouth closure
- inferior head works concentrically to glide the condyle forward during end stage opening
- Consequently one works with opening and one works with closing
How can cartilage damage in the cervical spine effect balance?
- Loss of mechanoreceptor in the cervical spine leads
- decreased proprioceptive feedback leads to
- loss of eye hand coordination, balance, and postural adjustment
How does a dowager’s hump form?
Chronic hypomobility of the C/T junction secondary to accumalation of of subcutaneous fat tissue with hypomobility
What are the consequences of a forward head position on the CT junction?
- increased potential for dowager hump
- pain cascade with chronic tension on intraspinous ligaments
- sympathetic influences on the cervical sympathetic chain
How does the foreword head position effect the shoulder?
- The scapula will protract and internally rotate
- scapular position moves the glenoid anterior, inferior and Lateral (?)
- scapular position moves the AC and AC joints into a closed pack position
- Thoracic spine losses the ability to extended decrease the ability of the shoulder to flex and abduct
- scapular position also places the medial scapular muscles in a lengthened position predisposes them to fatigue
- RTC is at greater risk for impingement secondary to ROM loss at AC, SC, scapula, and thoracic spine
What impact does the forward head position have on the anterior soft tissue structures?
- Scaleni are in a shortened position and can elevate the first rib
- the deep cervical fascia becomes shortened which can compress the neurovascular bundle
- the infrahyoids which includes the omohyoid are in a shortened position
- accessory respiratory muscles are engaged because the flexed CT junction places the first rib in a depressed position
What is the prevalence of Bruxism?
20% of the population and decreases with age and women have it more than men
what is bruxism?
nocturnal teeth grinding
What is it called when someone grinds there teeth during the day?
bruxomania
Describe the pathology of bruxism?
- it actually thought to be a “normal human parafunction”
2. the focus of the treatment should be on tissue specific involvement of the TMJ
How would you test AROM of the TMJ?
- vertical opening with habitual pattern and corrected pattern
- lateral movement with teeth slightly apart
- protrusion and retrusion
- Note bite position
- teeth clasping noting shearing and clapping sounds
- bite on cotton roll for distraction (B) and unilateral to distraction ispsalateral and compression contralateral
Name the moving parts of the cranium?
TMJ
What other structures play a role in the region interdependence of the TMJ?
- cranium
- cervical spine
- thoracic spine
- TMJ
- Scapula and shoulder
- first rib/sternum
- hyoid
What is the articular eminence?
superior articulating bone of the TMJ
What is Gnathology?
study of bite and the TMJ as the cause of TMJ syndrome
What is barohypoacusia?
stuffiness of the ears caused by tensor veli palatini
What is the function of tensor veli palatini?
open the eustachian tube
What is trismus?
muscle spasm that limits the opening of the mouth
How does the forward head position effect the position of the TMJ?
- FHP increases tension on the hyoid muscles pulling the mandible in the retrusion
- FHP place the manidbile in a posterior position in the TMJ because gravity influence in position due to its sling like structure
Describe the sagital plane muscle synergy of the TMJ during swallowing?
- Hyoid elevated by the suprahyoids
- suprahyoids depress mandible so massater and temporals fire to prevent
- Infrahoids are also active thus creating a flexion moment of the cranium
- flexion moment of cranium requires cervical extensors to stabilizes cranium
- cervical extenors requires cocontraction of longus coli to prevent shearing
What are the horizontal planes of the cranium?
- bipupilar
- otic
- occlusive
What is the stability of the TMJ dependent on?
- the anti-gravity muscles due to its sling like function and orientations
- it always operates in an open chain environment
How can tooth grinding or splints create short term improvements, but result in longer term TMJ problems
- If occlusion problems starts with a dysfunction of the antigravity system (muscle syngeries and postural orientation) you haven’t addressed the root
- the grinding quickly removes the symptoms, but leave the cause
- additionally you are now left with abnormal joint load because of uneven occlusial patterns
How do postural changes effect the tone of the muscle mastication?
- with postural changes the oclusion pattern is changed
- to correct the oclusial pattern you have to create an imbalance in muscle synergies
- imbalanced synergies leads to elevated muscle tone
How does muscle guarding in presence of pain decrease the muscle strength?
IF the resting tone is elevated due to pain you will have fewer motor units available to recruit once the muscle tries to contract
How is development of tooth position in the mouth regulated?
- A balance of internal (inside the teeth) and external (outside the teeth) forces
- eternal forces include the buccinator and orbicularis oris
- internal force is mainly the tongue
- functions such as sucking, chewing and swallowing all play a key role in developing the shape of the oral cavity
How does the tongue position effect the breathing pattern
a tongue in resting position will promote diaphragmatic breathing and prevent mouth breathing
How is the tongue supposed to move during swallowing?
back and down
What are two functional pathologies of the tongue that can adversely effect the oral cavity
- excessive tongue exploration in children
2. language that requires certain sounds incorporates tongue thrust such as “th”
What is developmental theory behind thumb sucking?
- babies need 120-130 minutes of sucking a day
2. if they don’t get enough sucking time thy might try and suck the thumb to make up for it.
How can thumb sucking effect the development of the oral cavity
- thumb forces the tongue to the floor of the oral cavity
- the tongue pushes the lower teeth out
- the lower teeth push the upper teeth out
- the lips can develop soft tissue shortening creating a “kissing mouth”
- “kissing mouth” further decreases external forces for balancing internal forces
How can you recognize a mouth breather child?
- forward head and rounded shoulders
2. “kissing mouth”
What is the boney anatomy of the TMJ?
- mandibular fossa on the inferior surface of the temporal bone
- condylar process on the mandibular bone
How can you tell that the TMJ is a non-weight bearing structure?
- the mandibular condyle is composed of spongy bone under a thin layer of compact bone
- the joint surface is covered by avascular fibrocartilage
- its fibrocartilage is thinner anteriorly and thicker posteriorly
How is the condylar head shaped?
- It is biconvex and oval shaped
- longer horizontally (15-20mm) than A/P (8-12mm)
- four different shapes
- slight superior convexity (58%)
- flattened superior surface (27%)
- pointed or angulated surface (12%)
- bulbous or rounded condyle (3%)
What is the shape of the temporal articular surfaces of the TMJ?
- glenoid fossa is concave A/P (sagital) and concave transverse/frontal plane, but it is completely covered fibro cartilage that is ticker posteriorly
- articular eminence convex A/P (sagital) and concave transverse
What plane are the condylar head oriented in?
15 degrees from the frontal
How can the TMJ have two joints?
there are two distinct articulations (1) glenoid fossa and superior portion of the disc (2) inferior portion of the disc and the condylar head
What are the different parts of the disc of the TMJ
- anterior
- posterior
- middle
Describe the shape and attachments of the anterior portion of the TMJ disc
- resembles a baseball cap with the visor forward
2. attaches to lateral ptyerigoid and anterior joint capsule
Descirbe the innervation and blood supply to the TMJ disc
- Both the anterior and posterior have a nervous and vascular supply
- The Posterior portion has a highly vascularized areolar tissue between the superior and inferior stratum
- the middle portion has no innervation or blood supply
Describe the shape of the posterior portion of the TMJ disc
- Thickest portion of the disc
2. divided into a superior and inferior stratum
How are the superior and inferior stratum of the TMJ disc different?
- superior is elastic attaching to the glenoid spine, posterior capsule and tympanic plate
- inferior spine is collagenous attaching to the mandibular condyle
What are the attachments and what is the shape of the middle portion of the TMJ disc?
- thinnest portion and is biconcave
- serves as the weight bearing part of the disc
- it has no capsular attachments
- medial and lateral collateral ligaments attach to the mandibular condyle
How is TMJ disc stability created
it is a balance of the anterior action of the lateral pterygoid and the posterior action of the elastic superior stratum
