![]() The lower head arises from the lateral surface of a lateral pterygoid plate of the splenoid bone. The upper head arises from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone.The lateral pterygoid is a short thick muscle with two head. It also assists the lateral pterygoid muscle with side to side mandibular motion to help with the grinding of food. The medial pterygoid muscle functions to assist with elevation and protrusion of the mandible. Its blood is supplied by a pterygoid branch of 2nd part of the maxillary artery.It is innervated by the branch of the main trunk of the mandibular nerve.The insertion of the medial pterygoid forms a tendinous band with the insertion of the masseter called the pterygoid-masseteric sling The medial pterygoid muscle fibres converge inferiorly, forming a tendon that inserts on the medial ramus of the mandible posterior and inferior to the mylohyoid groove of the mandible.The superficial head of the medial pterygoid has its origin from the maxillary tuberosity of the inferior maxilla and the deep head originates from the medial surface of the lateral pterygoid plate of the sphenoid bone. The medial pterygoid muscle originates on the pterygoid process, which is a downward pointing process that extends from the sphenoid bone.The deep head of the medial pterygoid is larger than the superficial head. The medial pterygoid muscle is a thick rectangular muscle with a superficial head and a deep head. It also contributes to side to side grinding movement. The posterior fibres of the temporalis muscle function to retract the mandible.The function of the anterior and mid fibres of the temporalis muscle is to elevate the mandible.Blood supply of the temporalis muscle is from the deep temporal part of the maxillary artery and the middle temporal branches of the superficial temporal artery.It is supplied by the deep temporal nerve which is a branch from the anterior division of the mandibular nerve.The temporalis muscle fibres converge inferiorly forming a tendon that exists the temporal fossa passing underneath the zygomatic arch and inserting on the coronoid process of the mandible. It originates from the temporal fossa to the inferior temporal line of the lateral skull. It is a fan-shaped muscle that fills the temporal fossa, with anterior fibres that have a vertical orientation, mid fibres have an oblique orientation, and posterior fibres have more of a horizontal orientation. The deep fibres are important stabilisers of the TMJ. The intermediate and deep muscle fibres of the masseter function to retract the mandible and the superficial fibres function to protrude the mandible.The major function of the masseter muscle is to elevate the mandible, approximate the teeth.Its blood supply is derived from the masseteric artery, which emerges from the maxillary artery. It is innervated by the mandibular division of the Trigeminal Nerve. ![]() The firers converge inferiorly forming a tendon that inserts at the outer surface of the mandibular ramus and the coronoid process of the mandible. The fibres of the muscle originate from the inferior zygomatic arch and the anterior two-thirds of the zygomatic arch with a connection to the posterior aspect of the zygomatic bone. It consists of three layers that blend anteriorly: the superficial layer, intermediate layer, and deep layer. ![]() It is a rectangular muscle that covers most of the lateral aspect of the ramus.
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