Action of the muscle marked (with arrow) on mandible is
Elevation
Depression
Retraction
Protraction
Muscle marked - temporalis Elevators of mandible: MTM Masseter Elevation, protraction Temporalis Elevation retraction Medial pterygoid Elevation, protraction Depressors of mandible Lateral pterygoid Depression, protraction Mylohyoid Depression Ant. belly of digastric Depression Muscle of mastication develop from 1st pharyngeal arch Nerve - mandibular branch of trigeminal.