Hair Dimensions
People describe their hair as being thick or thin, coarse or fine. What they are usually talking about is the amount of coverage their hair gives to the head. This coverage depends on two things: how many hairs there are, and the thickness (diameter) of each hair shaft.
People vary a lot in how many hairs they have, and also in how closely together they grow. The 'average' person has around 100,000 hairs, but people with very dense hair may have as many as 150,000.
The diameter of the hair shaft varies too. It is usually around 57-90 µm in Europeans. This is much less than in Asians, in whom it can be 120 µm. (These are general figures, representing a wide range of values.)
Hair that is both dense and thick looks completely different from that of someone who has fewer and finer hairs.
