Mastication Essay

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Give an account on muscle mastication and discuss how they contribute to jaw movements Mastication is the action of breaking down of food in preparation to deglutition. The breaking down action of food is a highly organized complex of neuromuscular and digestive activities. The duration and forces developed in mastication vary within and between individuals and for the type of food being chewed. For mastication to occur, movements of the jaw must be permitted. In humans, the mandible, or lower jaw, is connected to the temporal bone of the skull via the temporomandibular joint, an extremely complex joint which permits movement in all planes. The mandible is the only bone that moves during mastication and other activities such as talking. Jaw movements are among the most complex and unique movements performed by the human body. The mandible, unlike any other bone in the body, is slung between two nearly symmetrical joints, which are close to being the mirror image of one another and movement occurs by the contraction of muscles. These muscles originate on the skull and insert onto the mandible. There are four chief muscles of mastication which act on the mandible. These muscles are: masseter muscle, temporalis muscle, lateral pterygoid muscle and medial pterygoid muscle. Each of these muscles is paired and there is one on each side of the mandible. Firstly, the masseter muscle is a thick muscle consisting of two portions, superficial and deep. The superficial portion arises from the thick, tendinous aponeurosis from the zygomatic process of the maxilla, and from the inferior border of the zygomatic arch. The fibres pass downwards and backwards and are inserted onto the lateral surface of the ramus of the mandible. The deeper portion of the masseter muscle is much smaller and arises from the medial surface of the zygomatic arch and its fibres pass downwards and

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