The masticatory system is the functional unit of the body primarily responsible for chewing, speaking and swallowing. The system is made up of bones, joints, ligaments, teeth and muscles. The system of mastication is a highly refined and complex unit. Gaining an in-depth knowledge into its biomechanics and functional anatomy is necessary to the study of occlusion. The mandible is a horseshoe-shaped bone supporting the lower teeth and makes up the lower portion of the facial skeleton. It is suspended below the maxilla by ligaments, other soft tissues, and muscles, which provide the mobility required to function with the maxilla. The energy that moves the mandible and allows function of the masticatory system is provided by muscles. There are four pairs of muscles (left and right side of the mandible) that make up a group known as the muscles of mastication.