The external nose is generally considered to have a relatively static shape. Movement of the nose and the potential for change of external shape and the internal airway have been assessed by (1) cadaver dissection and (2) dynamic studies during a standardized series of facial expressions in 13 subjects; video recording of the movement of skin markers, electromyography, and moving magnetic resonance images. A standard description of muscle anatomy is presented. The dynamic investigations indicated the following. Video analysis showed the components of muscle action: dilatation, constriction of the nostril, depression of the tip, vertical contraction in the bridge, and elevation of the alar, in different expressions. Electromyography confirmed muscle actions during expression and phonation. Magnetic resonance imaging demonstrated large changes in the external shape of the nose and nasal aperture due to muscle actions. Muscle function should be given greater consideration in aesthetic and cleft rhinoplasty.