When analyzing a nose it is important to be precise and specific with terminology. Most nasal analysis systems use the following definitions: Nasal Length - The distance from Nasion (the break point where the base of the forehead intersects with the nasal bridge) to the Tip Defining Points (the fore-most and down-most positions along the nasal tip profile - this can vary from very distinct to indistinct depending on the curvature of angularity of the tip). Tip Rotation - The position of the tip in space relative to the nasal base. This is often measured using the angle subtended by the columella and the upper lip also known as the naso-labial angle. The larger the nasolabial angle, the more up-rotated the tip is. In order to avoid ambiguity it is a good idea to speak in terms of down-rotation and up-rotation. Notwithstanding, most surgeons use the term 'derotation' to refer to down-rotation. Tip Projection – The distance the Tip Defining Points extend forward from the face. Nasal length, tip rotation and tip projection are inter-related. Modifying tip rotation will have an effect on both tip projection and nasal length. If tip rotation is kept constant, then modifying tip projection will result in a proportionate change in nasal length. In summary then, derotation or down-rotation of the tip results in an increase in nasal length plus a decrease in tip projection, and therefore, the two are not the same. Mario J. Imola, MD, DDS, FRCSC, FACS.