The Classic TMJ skull with masticatory muscles (2-part) is ideal for active use in teaching and demonstrations. Demonstrate the function of the masticatory muscles with jaw occlusion, the initial stage of jaw opening and the movements of the mandible to the side and front. Removable skullcap. Now included with all 3B Scientific Anatomy models is the 3B Smart Anatomy app. This app allows users to register their 3B item to extend the warranty from 3 to 5 years plus free 1 year access to the 3B Smart Anatomy app which includes 23 Anatomy lectures, 117 interactive models and 39 quizzes.