In FUE, the extraction of intact follicular unit is dependent on the principle that the area of attachment of arrector muscle to the follicular unit is the tightest zone. Once this is made loose and separated from the surrounding dermis, the inferior segment can be extracted easily. Because the follicular unit is narrowest at the surface, one needs to use small micropunches of size 0.6–0.8 mm and therefore the resulting scar is too small to be recognised. The main anatomical limitation of the technique is that it is not possible to identify the bulge of the hair from outside and hence the procedure is blind. Also, since the hairs with intact unit splay at the lower end and diverge in different directions, the process of extraction can result in a higher transection rate. The procedure is also slow as each unit has to be pulled out slowly. However, with experience, the hand eye coordination and speed of the surgeon, transection rate can be improved.