SKIN RELIEF AND AGING 183 CHILDREN 90 • lO lO 270 ø 65 ø 8 Oø ARM AXIS Figure 4. Rose of directions for children's group. Coordinate is the number of subjects having the principal or secondary axis at each 15 ø step. 3. DENSITY AND DEPTH OF FURROWS (Figures 7, 8, and 9) a) The principal axis evolution in relation to age shows a decrease of line density in the aged group (24/cm 2 -- p 0.01). In children and adults, the densities of lines are identical (29/cm 2 - p 0.01). A very important increase of mean depth of furrows with age is found. The average depth of furrows in children is 33/am - p 0.001, in adults 41/am - p 0.01, and in aged subjects 60/am - p 0.001. Sometimes, the

184 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ADULTS 270 ø 50 ø 65 ø ARM AXIS Figure 5. Rose of directions for adults. Coordinate is the number of subjects having the principal or secondary axis at each 15 ø step. depth was 100/am for some subjects in the aged group. Figure 8 shows in detail the increase in depth of furrows with age. Furrow depth increases at forty for the principal axis and after that the variations are more individual and become very important. Some people keep shallow furrows throughout their lives.