In addition, the temporalis muscle contributes to grinding movements by moving the mandible from side to side. The contraction of the posterior, more horizontal fibers of the muscle produces a retraction of the mandible, pulling the jaw backwards. This function is largely produced by its anterior vertical fibres which are continually in action, opposing gravity when the mouth is closed. The temporalis muscle functions mainly as an elevator of the mandible. The muscle is innervated by the deep temporal branches of the mandibular nerve, and vascularized by the deep temporal branches of the maxillary artery and middle temporal branches of the superficial temporal artery. The tendon then inserts on the apex and medial surface of the coronoid process, and the anterior border of the ramus of mandible. Its muscle fibers converge anteriorly to form a tendon which runs deep to the zygomatic arch. This fan-shaped muscle arises from the entirety of the temporal fossa below the temporal line, as well as the deep surface of the temporal fascia. The temporalis muscle is a large, flat muscle that lies within the temporal fossa of the skull.
Temporalis, masseter, medial pterygoid and lateral pterygoid The muscles of mastication are muscles that attach to the mandible and thereby produce movements of the lower jaw. Key facts about the muscles of mastication Definition and function This article will introduce you to the anatomy and function of the muscles of mastication. Rotation, which produces side-to-side movements of the mandible.Īll muscles of mastication are innervated by motor fibers of the mandibular branch of the trigeminal nerve (CN V3), while the main arterial supply is derived from branches of the maxillary artery.Depression, which depresses the mandible and opens the mouth.Elevation, which elevates the mandible and closes the mouth.Retraction, which pulls the mandible backwards.Protrusion (protraction), which moves the mandible forwards.The masticatory muscles attach to the mandible, and thus produce movements of the lower jaw at the temporomandibular joint (TMJ) to enable functions such as chewing and grinding. The temporalis muscle is situated in the temporal fossa, the masseter muscle in the cheek area, while the medial and lateral pterygoids lie in the infratemporal fossa. The muscles of mastication are a group of muscles that consist of the temporalis, masseter, medial pterygoid and lateral pterygoid muscles. Muscles of mastication (Masticatory muscles)
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