What muscles are connected to the hyoid bone and are involved with the movement of the mandiable

what are the different functions of these muscles?

The infra and Supra hyoid muscles

Infrahyoid muscles statbilizehyoid

Suprahyoid muscle move the mandiable from the stable base of the hyoid bone

What is the function of the articular capsule at the TMJ?

What other ligamentous support is there about the TMJ?

Sorounds and stabilizes the TMJ and attaches the condyle to the fossa

The lateral colateral ligament running form the zygomatic arch to the TM capsule (Tempomandibular Ligament)

The disc (aka mensci) in the TMJ

Outer edged of the disc attach to the joint capsule

Does the articular disc of the TMJ divide the joint into two portions?

If so why is this important?

WHat movements does this allow?

The disc divides the TMJ into upper and lower portions

THis allows the TMJ to functions as it should by having rotation occur in the lower joint space and translation occur in the upper joint space

In the lower joint space rotation occurs while the disc is still inplace, in the upper joint space the disc attacts as a sled the condyle uses to move forward forward(the disc follows the condyle)

What is the normal opening of the mouth?

Where is this measured from?

Normal opening: 35-50 mm

This is measured from the middle of the centeral inscisors

10-15 mm

depression: later excersion

1:4 ratio

What are the 3 physiological movements of the Jaw and the capsular pattern?

What are the accessory movements?

Depression

Elevation

Protrusion/Retrusion

Capsular pattern is Depression

Accessory Movements: Translation, rotation, spin (only associated with lateral excersion, same side spins as athe side that is moved towards)

First roation then translation with the disc following the condyle

for elevation it is reversed

the condyles both translate at the same time down over the eminice disc following. There is no spin.

retrusion is translation back into the fossa

what is the rest position of the jaw?

how is this maintained?

Rest position of the jaw is teeth are slightly apart

this is is maintained via the Temporalis muscle

Diagrastric and Suprahyoid move are responsible for the spin (pull mandible down and back)

lateral Pterigoid: responsible for the forward translation of the mandiable

infrahyoid stabilized the hyoid so supra can pull mandible down and back

Temporalis with help from the masseter pull the condyle back (translation)

Medial Pterigoid: pulls the condyle up and forward (rotation)

Medial Pter.: Holds the ipsilateral side in place so that it can spine

Lateral Pterigoid: pulls the contra-lateral jaw forward and downs ward

Posterior Temporalis: hold the mandible horizontal during the movemnet

Lateral Pterigoids: Translate the mandible, also help to hold the mandible horizontal

Medial Pterigodis: keep madible horizontal

Deep and middle portions of the Masseter and the Posterior Temporalis (most horizontal) pull the condlye psoterieorly

Digastric and Geniohyoid: help to keep the mandible horizontal along with the elevators

Bruxism: grinding the teeth

trismus: inability to open, muscle spasms the inhibit the jaw from opening

What areas does the TMJ refer to?

What areas refer to the TMJ?

TMJ Refers pain to the C-spine, ear, teeth, head

TMJ reveice pain from: C-spine, head, teeth, heart

Bruxing or clentching (Stress)

Trauma: dental work, whiplash

Disease: RA

When depression the mandible and there is a click at the start of translation what is the positionofthe disc?

what does this occur?

when there is a click when elvating the mandible what it happening

the disc is positioned anteriorly to the condyle, occurs bc the condyle is recapturing the disc

elevating click: the disc is again dislocating

if there is a longer period of time before a click happens when depressing the jaw the disc is farther anterior(poor prog)

If there is a click ealier when closing the jaw then the disc is farther antior and therefore recapture earlier

The disc is traped between the condyle and emenice and it cannot be recaptured by the condyle therefore the TMJ cannot open

disc just stays anteriorly located