Oral Function - Muscles Flashcards
mandibular muscles
muscles of mastication
- Masseter
- Temporalis
- Lateral Pterygoid
- Medial Pterygoid
origin of masseter
zygomatic arch
insertion of masseter
lateral surface and angle of mandible
action of masseter
elevates the mandible (closing the jaw)
masseter in patients with clenching habit
tender
examining masseter
Place one finger intra-orally and the other on the cheek
origin of temporalis
floor of temporal fossa
insertion of temporalis
coronoid process and anterior border of ramus
action
elevates and retracts the mandible
- closing the jaw and retraction
temporalis is tender in patients who have….
bruxist habit
clenching and grinding teeth at night - parafunction
examining temporalis
Palpate its origin by asking the patient to clench the teeth together, because it is difficult to palpate the insertion area.
Digital palpation is performed between the superior and inferior temporal lines just above the ear, extending forwards towards the supra-orbital region
origin of lateral pterygoid
from the lateral surface of the lateral pterygoid plate
insertion of lateral pterygoid
anterior border of the condyle and intra-articular disc via two independent heads
- superior and inferior heads so 2 points of insertion
clinically important
inferior (top) belly of the lateral pterygoid attaches where
to the head of the condyle
the superior belly of the lateral pterygoid attaches where
into the intra-articular disc
jaw click is a sign of
spasm of lateral pterygoid
Tense pull disc = click
Limited mouth opening - improves with day and click will disappear
function of lateral pterygoid
protrudes and laterally deviates the mandible and the inferior head functions with the mandibular depressors during openings.
Lateral movement and opening of jaw
what does clenching and grinding do to the lateral pterygoid
clenching and grinding wears muscle out
as lateral deviation of the jaw as well as opening
- Physiotherapy or splint can reduce load on muscle
examining lateral pterygoid
Not accessible to manual palpation
Best examined by recording its response to resisted movement.
- Give idea on the muscle
There is a good correlation between the resisted movement test and the muscle being tender to palpation.
Test – try to open jaw and clinician pushes upwards, jaw move to one side and you push it the other way.
- Problem is causes pain
origin of medial pterygoid
deep head
- medial surface of lateral pterygoid plate
superficial head:
- tuberosity of maxilla
insertion of medial pterygoid
medial surface of angle of mandible
Masseter is from the lateral side.
- Together they hold the jaw like a swing
action of medial pterygoid
elevates and assists in protrusion of the mandible
examination of medial pterygoid
Because of the location of the medial pterygoid, on the inside of the jaw, this muscle is not available for palpation.
- It also does not respond well to resistive movement tests.
Therefore, unfortunately, there is no reliable way of examining this muscle.
following an injection, patient was unable to open the mouth fully on the following day.
which muscle was accidentally hit by the needle?
ID block coming from inside
- Inserted into area in cheek
- Medial pterygoid affected as from the inside
Try to avid bulk/mass of muscle when inject
Bone should be contacted to ensure correct position within the pterygomandibular triangle and not t hit soft tissues.
Hitting this muscle by the needle accidentally might cause “trismus”
