part 2 Flashcards
What functions does the medial pterygoid have?
- works synergistically with the masseter and temporalis to suspend and elevate the mandible
- protrusion of the mandible with teeth slightly apart is it most active state
- unilateral action creates lateral devation and works synergistically with the ipsalateral lateral pterygoid
- inhibited with active mandibular depression
What are the attachments of the medial pterygoid?
- lateral pterygoid plate of the sphenoid, pyramidal process of palatine bone, tuberosity of the maxilla
- inserts inferior and posterior part of medial ramus and angle of the mandible
What are the attachments of the lateral pterygoid?
Two heads
- upper- infratemporal crest and the interior lateral surface of the greater wing of the sphenoid TO the disc
- lower- lateral pterygoid plate of the sphenoid TO condylar neck and ramus of the mandible
What is the function of the lateral pterygoid?
- laterally deviation the mandible to the contralateral side
- eccentrically control position of the disc with mandibular elevation
How does shortening of the lateral pterygoid effect occlusion pattern?
- Premature contact anterior opposite
2. premature contract posterior same side
What muscle was once thought to be part of the temporalis muscle?
shenomandibularis
What are the attachments and innervation of the sphenomandibularis muscle?
- greater wing of the sphenoid
- temporal crest of the mandible
- branches of the buccal nerve off the mandibular nerve off of CN V
What TMJ muscle is theorized to contribute to cluster headaches and why?
- sphenomandibularis
2. it is thought spasm will compress the maxillary nerve against the posterior maxillary wall
What are the attachments of the masseter?
- Deep- posterior 1/3 of the inferior border of zygomatic bone and from the entire zygomatic arch TO superior half of the mandibular ramus and lateral surface of the coronoid process
- Superficial- lower surface of the zygomatic arch TO the mandibular angel and lower part of the ramus
What innervates the masseter?
Masseteric nerve from the anterior branch of the mandibular branch of CN V
What are the attachments of the digastric muscle?
ORIGIN- Two bellies
1.posterior- mastoid notch of the temporal bone and sometimes the styloid process of the of the sphenoid bone
2.anterior- digastric fossa of the lower border of the mandible close to the symphasis
INSERTs- the two bellies joint together passing through a tendonis loop that that perforates the stylohyoid muscle at the hyoid bone
What is the innervation of the styloid muscle?
- anterior belly- mylohoid branch of inferior alveolar of CNV
- posterior belly- facial nerve (CN VII)
What is the function of the digastric muscle?
- raises the hyoid bone
2. open the jaw when the hyoid is stabilized from below
What are the attachments of the stylohyoid muscle?
styloid process TO hyoid bone posterior superior
What innervates the stylohyoid?
CN VII facial nerve
What are the attachments of the omohyoid?
- upper margin of the scapular near suprascapular ligament (sometimes on the ligament) TO the hyoid bone
- TWO bellies meet at a central tendon held down by the SCM
What is the innervation of the omohyoid?
ansa cervicalis C1-3
What function does the omohyoid serve?
the omohyoid assists in swallowing, vomiting, respiration, and some scapulo-clavicular actions
What impact does thumb sucking having on the hyoid muscles and what other pathology causes similar changes?
- it elevates the hyoid so that the suprahyoids shorten and the infrahyoids lengthen
- forward head position has a similar impact
What are the attachments of the styologlossus muscle?
anteriorlateral surface of styloid process of the temporal bone and styolmandibular ligament TO tongue and hypoglossus muscle
What type of symptoms or patients might have styloglossus disfunction?
- people with difficulty swallowing because the styoglossus assists in tongue muscle move the bolus back and up
- mouth breathers might have shortening of the styologlossus
What are the attachments of tensor veli palatini
FROM sphenoid bone
-base of the scaphoid fossa at the bottom of the pterygoid plate
-angular spine of the sphenoid
-lateral wall of eustachian tube
TO palatine aponerurosis and horizontal plate
What is the function of tensor veli palatini
- tense and raise the soft palate during swallowing allow room for the bolus
- works with levator veli palatini to to open and close the eustachian tube during yawing, swallowing, and sneezing
What muscles can contribute to hypobaroacusia?
tonic contraction of the medial pterygoid can increase tension on tensor veli palatini leading to closure of the eustachian tube
What are the four main ligaments of the TMJ?
- lateral or temporomandibular
- internal lateral or sphenomandibular
- stylomandibular
- mandibular-malleolar or ligament of Pinto
Describe the shape and attachments of the temporomandibular or lateral ligament?
- fan shaped
- lateral surface of the zygomatic arch and articular eminence TO
- postero-lateral aspect of the neck of the mandible
What are the functions of the lateral or temporomandibular ligament?
- strengthens the TMJ
2. prevent excessive retrusion and compression of posterior structures
How can you isolate lateral temporomandibular or lateral ligament pain?
- passive retrusion of the mandible will tension the ligament and posterior structures
- passive opening of the mouth will decrease the posterior pressure and keep the tension on the lateral ligament
How would you differentiate between tempromandibular and sphenomandibular ligaments?
- initial opening of the mouth is the lateral ligament
2. terminal opening is resisted by sphenomandibular and stylomandibular
What is the function of the sphenomandibular ligament?
- its considered an accessory ligament and the function is not clear
- may act to provide a restraining force to maintain opposition of condyle, disc and temporal bone
Describe the attachments of the sphenomandibular ligament
1angular spine of the sphenoid
2.lingula of the mandible at the mandibular foramen
How would you incriminate the sphenomandibular ligament?
protrusion, jaw opening, contralateral lateral deviation
Describe the attachments of the stylomandibular ligament
- styloid process of the temporal bone
2. medial angle of the ramus
What motion does the stylomandibular ligament resist?
anterior translation of the mandible
How would you incriminate stylomandibular ligament?
passive opening with protrusion
What are the attachments of the ligament of Pinto
the mandibular-malleolar ligament attaches to the neck of the malleus and tympanic membrane TO medio-posterior-superior capsule or meniscus of TMJ
How does the TMJ directly effect the ossicles of the ear?
The Mandibular-malleolar ligaments run directly from the TMJ capsule or disc to the malleus bone there for movement of the the capsule or disc changes the orientation of the ossicles
What is the function of the TMJ disc and how it accomplishes its function
- To fill the constantly changing space between the tow bones of the condyle and the fossa
- it is somewhat mobile allowing for many minute movements to accommodate for the changing space
- fibrocatilagenous nature allow for increased flexibility
- the thin intermediate zone also allows for pliability and adaptation to the changing surgfaces
How is the TMJ capsule different than other joint capsules
- From the disc down it is taut
- from the disc up it is loose
- the lateral aspect is kept tight by the temporomandibular ligament while the rest of the capsule is unsupported and loose
Describe the articular innervation of the TMJ
- there are both primary and accessroy articular nerves
- primary from the auriculotemporal nerve
- accessory from the massetric, deep temporal and lateral pterygoid nerves
Describe the neural pathway of the primary articular nerves of the TMJ
trigeminal nerve > mandibular branch > auriculotemporal posterior and lateral
Describe the neural pathway of the the accessory articular nerves of the TMJ
- deep temporal innervates the anterior and medial joint
- lateral pterygoid of the mandibular nerve innervates anterior medial capsule
- anterior auricular arises from masseteric nerve to innervate anterior lateral capsule
Describe the behavior of type I mechanoreceptors with TMJ
- slow adapting
- long latencies (.8 to 2.5 seconds)
- adapt within 20 seconds
- demonstrate a range of thresholds
- constant afferent contributions to control mandibular musculature
Describe the behavior of type II mechanorecptors with TMJ
- rapidly adapting (within seconds)
- act as on-off receptors
- entirely reflexogenic
- very short latencies
- respond briefly at the onset of jaw movement
Describe the behavior of type III mechanorecptors in the TMJ
- slow adapting
2. provide powerful refelxogenic response
How does the condyle of the TMJ move during mouth opening?
- during the first 6-10mm of opening the condylar heads spin around a horizontal axis within the mandibular fossa
- as the mouth opens further they continue to rotate and an anterior translation takes the condylar heads into the articular eminences
- the rotation is thought to take place in the lower joint while the translation is thought to take place in the upper part of the joint
Describe the movement of the TMJ disc with mouth opening and closing
- during opening the superior stratum pulls the disc posteriorly to keep in properly oriented on the head of the condyle
- during closing the lateral pterygoid contracts to reorient the disc on the head of the condyle to counter act the tension of the superior stratum
The primary pathology of the TMJ is associated with what factors?
disturbances in occulsion couple with microtrauma
What are some signs and symptoms of otomandibular syndrome?
- ear pain
- congestion
- tinnitus
- loss of equilibrium
- ear pressure
- conductive hearing loss
- abnormal sounds in the ear
What muscles does CN V innervate
- muscles of massitication
- mylohyoid
- anterior belly of digastric
- tensor tympani
- tensor veli palatini
