Muscles of Mastication Flashcards
4 True Muscles of Mastication
- Medial Pterygoid
- Lateral Pterygoid
- Temporalis
- Masseter
Nerve innervation of the muscles of mastication
Trigeminal
Origin of Medial Pterygoid
Medial surface of the lateral pterygoid plate and pterygoid fossa
Insertion of Medial Pterygoid
Medial surface of the ramus and angle of mandible, on the interior surface
Action of Medial Pterygoid
Elevate and laterally deviate
Origin of Superior Head of Lateral Pterygoid
Infratemporal Crest (great wing of sphenoid bone)
Origin of Inferior head of Lateral Pterygoid
Lateral surface of lateral pterygoid plate
Insertion of Lateral Pterygoid
Articular disc of TMJ and neck of mandibular condyle
Action of Lateral Pterygoid
Can actively depress the mandible, the only muscle of mastication that can do this
Temporalis Origin/Insertion/Action
O: Temporal Line of the Temporal Fossa
I: Coronoid process and anterior border of mandibular ramus
A: Elevate the mandible, retract mandible
Superfical Part of Masseter O/I/A
O: Zygomatic process of maxilla and anterior 2/3 of inferior border of the zygomatic arch
I: Angle and lower lateral ramus of mandible
A: Elevate mandible, centric occlusion, protrusion
Deep Part of Masseter O/I/A
O: Inner surface of posterior 1/3 of zygomatic arch
I: Superior part of mandibular ramus and lateral surface of coronoid process
A: Retract the jaw when it has been protruded
Accessory muscle of mastication
Buccinator
Action and Innervation of Buccinator
A: Compresses cheek and manages food bolus
Innervation: CNVII (Facial)
Lateral Boundary of Pterygomandibular Space
Medial surface of mandibular ramus
Medial Boundary of Pterygomandibular Space
Lateral surface of medial pterygoid
Superior Boundary of Pterygomandibular Space
Lateral Pterygoid
Inferior Boundary of Pterygomandibular Space
Insertion of medial pterygoid
Contents of Pterygomandibular Space
- Lingual Nerve
2. Inferior alveolar nerve and artery
Innervation of Muscles of Facial Expression
Derived from 2nd branchial arch, facial nerve (CNVII)
9 Groups of 2
- Round
- Nose
- Zygomatic bone
- Lip Elevators
- Angle of the mouth
- Lower Lip
- Cheek
- Top
- Exceptions
2 Round Landmarks
Orbicular Oculi
Orbicularis Oris