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The lateral pterygoid inserts on the neck of the mandibular condyle and articular disc; its inferior head contracts to pull the condyle anteriorly along the articular eminence during protrusion, producing forward translation in the glenoid fossa. Electromyographic studies show it is the principal muscle active during this forward movement, unlike the masseter, temporalis, or medial pterygoid, which mainly elevate or assist in minor protrusion but do not drive condylar translation [Murray, 1999, PMID 10217518].