The shape and orientation of the tip are given by the alar cartilages. Its dynamics is influenced by the depressant muscle of the nasal septum, the common elevator of the upper lip and nose.
– Projection of the tip, depth of the radix, length of the nose
Several rules can be used to calculate the correct projection of the tip:
1) The ratio 1: 2: 3
The projection of the point (2 in the image), defined by the distance between the alogenian groove and the cartilaginous domes,must represent two thirds of the length of the nose (3 in the image) and must be twice the distance nasion (the most recessed point of the naso-frontal depression) and the internal canthus (1 in the image).
2) The projection is adequate when 50-60% of the tip is in front of the vertical which passes through the upper lip and if it is equal to 60-65% of the length of the nose.
3) Rule of the Crumley triangle: the ideal projection is that which makes it possible to draw a right triangle whose sides respect the ratio 3: 4: 5 (on the image) of the triangle of Crumley.
The rotation is defined by the opening of the nasolabial angle which must be between 90 ° -100 ° for the man and 95 ° -110 ° for the woman.
For the rotation-projection of the point, it is necessary to discuss the part of the visual illusion: the convexity of the dorsum gives a feeling of falling peak even though the naso-labial angle can be normal; an exaggeratedly concave dorsum will give a visual impression of excessive rotation.
- The Definition is based on characteristics that are not always met.
1) Visualization of the cartilaginous reliefs when a skin too thick does not mask them.
2) Subtle depression of the supra-tip, automation of the tip when its projection slightly exceeds that of the dorsum.
3) Double break lobulo-columellaire which makes apical lobule a separate element of the columella.