Muscles of Mastication & TMJ PDF

Functional Human Anatomy Muscles of Mastication TMJ D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D  Long thoracic n Upper trunk brachial plexus Today’s Overview Muscles of Mastication Identify, attachments, actions, innervation I...

Functional Human Anatomy Muscles of Mastication TMJ D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D  Long thoracic n Upper trunk brachial plexus Today’s Overview Muscles of Mastication Identify, attachments, actions, innervation Infratemporal Fossa Identify structures located in this region and their anatomical relationship to each TMJ  Temporal fossa: temporal, sphenoid, parietal, frontal bones Parietal Frontal sphenoi d Tempor al Movements of Mandible Elevation-temporalis, masseter, med pterygoid Depression-lat pterygoid, digastric Protraction (protrusion/mandible moves forward)  lat pterygoid (prime mover) & med pterygoid Retraction (mandible moves backward)  temporalis (post fibers) Lateral Movements  ipsilateral - temporalis & masseter (pull)  contralateral - med & lat pterygoid (push)  Meaning: to move your jaw to your right: contract R temporalis, R masseter & contract L medial and L lateral pterygoid Temporalis Muscle Arises from floor temporal fossa & deep temporal fascia To medial surface, apex, anterior & posterior borders of coronoid process of mandible, & anterior border of ramus of mandible AXN - anterior fibers-elevation of mandible (to close mouth & teeth) posterior fibers-retract mandible Innervation: mandibular branch of CN V (V3) Arises from floor temporal fossa & deep temporal fascia To medial surface, apex, anterior & posterior borders of coronoid process of mandible, x & anterior border of ramus of mandible  Temporalis Muscle Coronoid process of mandible To: medial surface, apex, anterior & posterior borders of coronoid process of mandible, & anterior border of ramus of mandible Ant border ramus of mandible Masseter Muscle Arises from inferior border & med surface of zygomatic arch  Arch includes zygomatic bone & temporal bone To the angle and lateral aspect of ramus of mandible AXN  powerful elevator of mandible Innervation-mandibular branch of CN V (V3) Inf border & medial surface zygomatic arch to the angle and lateral aspect of ramus of mandible Lateral Pterygoid-(2 heads) Upper-infratemporal surface & crest of greater wing of sphenoid Lower-lat surface of lat pterygoid plate To-ant aspect mandibular neck, articular capsule & TMJ disc AXN chief protractor; depresses mandible Innervation-mandibular branch of CN V (V3)  Upper head: infratemporal surface & crest of Grtr Wing of sphenoid Upper & Lower heads of Lateral Ptyergoid Mandibular neck, artic capsule, TMJ disc Lower head: lat surface of lat pterygoid plate  Sphenoid bone in yellow Palatine bone Lower head: Lat surface of lateral plate of sphenoid bone Medial Pterygoid-(2 heads) Med surface of the lateral pterygoid plate & palatine bone & tuberosity of maxilla To - medial surface of mandibular angle AXN elevate mandible; protraction of mandible Innervation-mandibular branch of CN V (V3) lat Med surface of m lateral e ptyergoid plate d Med surface of angle of mandible Infratemporal Fossa Irregularly shaped deep space located: Infratemporal Fossa  inferior to the zygomatic arch  deep to the ramus of the mandible and  posterior to the maxilla bone Contents  Temporalis ms. (Inferior aspect)  Med and Lat Pterygoid mm. maxilla  Maxillary a. & venous plexus  Nerves to ID: mandibular, inferior alveolar, lingual, buccal (branches of CN V)  Infratemporal fossa Contents  Temporalis ms. (Inferior aspect)  Med and Lat Ptyergoid mm.  Maxillary a. & venous plexus  Nerves to ID: mandibular, inferior alveolar, lingual, buccal Temporomandibular Joint Diarthrodial (synovial) joint Articulation between: articular tubercle & mandibular fossa of temporal bone (in pink) & mandibular condyle of mandible (grey) Complex- bc of articular disc Disc divides joint into 2 separate compartments Protraction and retraction occur in the superior compartment Elevation and depression occur in the inferior compartment To depress mandible: the head (condyle) of the mandible and articular disc must move anteriorly on the articular surface until the head lies inferior to the articular tubercle Loose joint capsule Shape- classified differently depending on reference: modified hinge (Moore & Dalley) or bicondylar TMJ movement  Postglenoid tubercle Mandibular fossa of temporal bone Articular tubercle of Mandibular condyle temporal bone Lateryal ptyergoid Buccinator fyi TMJ cont. ligamentous support in region Lateral temporomandibular lig Thickening of the joint capsule Prevents posterior dislocation of the jt with the postglenoid tubercle Sphenomandibular lig Connects the lingula of mandible to the cranium via the spine of the sphenoid bone Stylomandibular lig Connects the mandible to the cranium via the styloid process of the temporal bone TMJ cont. Innervation-V3 Dislocation  Posterior not common  Anterior (excessive contraction of lat ptyergoids while opening mouth); mandible stays depressed and unable to close mouth Clicking: delayed movement of the disc; may indicate tear of disc Can you? List all of the muscles of mastication, Classify the TMJ according their innervation, attachments and to # of articular surface actions. and shape. Explain the movements of the Identify soft tissue mandible and what muscle(s) is/are supporting structures responsible collectively for elevation, around the TMJ depression, protrusion, retraction. Explain what happens at Identify the boney landmarks and muscle attachments on the mandible, the TMJ when you temporal, sphenoid, zygomatic bones depress (open your mouth) and elevate (close your mouth) your mandible