Lesson Summary Students build a second model to emulate the movement of the thumb, with tendons and ligaments that make the thumb operate properly. Teacher Background Some muscles that move the finger and thumb are in the arm.  These muscles have long tendons that stretch down to the thumb.  Ligaments attach bones to bone.  Some ligaments serve as guide through which tendons run. Set-up/Management Tips It is important the teacher make a thumb model prior to teaching the lesson in order to be familiar with how it works. Locate arm and hand poster and the arm muscle transparency in the kit. Cut string prior to teaching lesson. Have response sheet ready for assessment at the end of the activity. Literacy Support Books Available Through VAST Mediagraphies: (see Literacy Links) Science Stories Space Race Scientific Vocabulary The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: ligament