MUSCLES OF MASTICATION THE MUSCLES THAT ALLOW CHEWING AND MOUTH CLOSING TO OCCUR THESE ARE THE FOUR SETS OF MUSCLES: 1. TEMPORALIS 2. MASSETER 3. MEDIAL PTERYGOID 4. LATERAL PTERYGOID Just to let you know……..the “P” in Pterygoid is silent so it is pronounced “Terygoid”! THE TEMPORALIS: This muscle RAISES the jaw. If you close your mouth and clench your teeth, put your hands on either side of your Temples and you will feel your TEMPORALIS muscles! THE TEMPORALIS: Point of origin - Temporal bone of the cranium Point of insertion - Coronoid process of the mandible passing under the zygomatic arch (cheek bone) Action - raises jaw - Pulls the mandible backwards and closed THE MASSETER: This muscle also RAISES the jaw. If you close your mouth, clench your teeth and place both your hands on your cheeks you will feel your MASSETER muscles! THE MASSETER: Point of Origin - Outer surface of Zygomatic arch Point of Insertion - Outer surface of Mandibular ramus and angle Action - Closes the mandible Just in case you hadn’t noticed…...it always on the OUTER surface LET’S RECAP WHAT WE HAVE LEARNT SO FAR…….. TEMPORALIS (temporal bone Would be here) MASSETER (M for mouth - near your mouth) THE MEDIAL PTERYGOID: The MEDIAL PTERYGOID closes the jaw (mandible) and moves the jaw from side to side. The MEDIAL PTERYGOID is below the LATERAL PTERYGOID…..you can remember this as it is closest to the mandible: M=Mandible M=Medial THE MEDIAL PTERYGOID: Point of Origin - Medial pterygoid plate at the base of the cranium Point of Insertion - Inner surface of the Mandibular Ramus and angle Action - Closes the mandible THE LATERAL PTERYGOID The LATERAL PTERYGOID consists of two sets of muscles: Both muscles contracting brings the mandible forward – To bite the anterior teeth tip to tip. One muscle contraction pulls the mandible to the opposite Side. THE LATERAL PTERYGOID Point of origin: Lateral pterygoid plate at the base of the cranium Point of insertion: Head of the mandibular condyle and into the Temporomandibular joint (TMJ) meniscus. Action: Both muscles contracting brings the mandible forwards to bite the anterior teeth tip to tip, one muscle contracting pulls the mandible to the opposite side LET’S RECAP THE PTERYGOID MUSCLES THE MUSCLES OF MASTICATION:.