The locomotion and movement are performed by bones, muscles, and joints. Bones together form the skeletal system and also form attachment surfaces for muscles. Muscles consist of origin, insertion and belly. The origin and insertion are points where muscles are attached to the bones by tendons. Belly of muscles rest on the bone and carry out contraction and relaxation. Muscles form around 40% of total body weight. In adult, there are over 650 muscles seen.