Muscles Of Mastication Flashcards
What are the muscles of mastication
Join to the mandible to allow for movement during chewing and grinding
5 main movements of mandible allowed by muscles of mastication
Forwards (protrusion)
Backwards (retraction)
Up/close (elevation)
Down/open (depression)
Side to side (rotation)
Muscles of mastication clinical relevance
Impact of inferior dental blocks (hematomia, trauma)
Pain during mastication
Trismus (difficultly opening)
Clenching and grinding (masseter pain)
Principle muscles of mastication
Masseter
Temporalis
Lateral pterygoid
Medial pterygoid
2 parts of masseter
Superficial
Deep
Masseter
Thick quadrilateral muscle
Most powerful of muscles of mastication.
Origin and insertion of superficial part of masseter
Origin - anterior 2/3rds lower border of zygomatic arch.
Insertion - superficial surface of the ramus of mandible.
Origin and insertion of deep part of masseter
Origin - posterior 1/3rd of lower border of whole medial surface of zygomatic arch.
Insertion - ramus above angle of mandible (superior to superficial)
Action of masseter muscle
Fibres contract to close/elevate the mandible
Innervation and blood supply for masseter
Nerve - masseteric nerve (anterior division of mandibular nerve).
Blood - temporal and maxillary artery
What gland duct passes through masseter muscle
Parotid gland duct
Origin and insertion of temporalis
Fan shaped muscle of either side of head.
Origin - whole of temporal fossa, bound at top by inferior temporal line, converge and descend into tendon that passes through zygomatic arch.
Insertion - top and medial surface of coronoid process and ramus of mandible.
Action of temporalis muscle
Anterior fibres run vertically and elevate the mandible.
Posterior fibres run obliquely and horizontally to elevate the mandible and retract head of condyle back into glenoid fossa.
Nerve and blood supply of temporalis
Nerve - anterior division of mandibular nerve
Blood - superficial temporal and maxillary arteries
A short, thick muscle, triangular in shape and arises from 2 heads
Lateral pterygoid
Origin and insertion of upper head of lateral pterygoid muscle
Origin - infratemporal surface of greater wing of sphenoid bone.
Insertion - pterygoid fovea on anterior of neck of mandible.
Some fibres may insert with TMJ structures.