A healthy fingernail has the function of protecting the distal phalanx, the fingertip, and the surrounding soft tissues from injuries. It also serves to enhance precise delicate movements of the distal digits through counter-pressure exerted on the pulp of the finger. The<unk> then acts as a counter-force when the end of the finger touches an object, thereby enhancing the sensitivity of the fingertip, although the<unk> itself has no nerve endings. Finally, the<unk> functions as a tool enabling a so-called "extended precision grip" (e.g., pulling out a splinter in one's finger), and certain cutting or scraping actions. Growth The growing part of the<unk> is under the skin at the<unk> s proximal end under the epidermis, which is the only living part of a<unk>  In mammals, the growth rate of<unk>  is related to the length of the terminal phalanges (outermost finger bones). Thus, in humans, the<unk> of the index finger grows faster than that of the little finger; and fingernails grow up to four times faster than toenails. In humans, fingernails grow at an average rate of approx. a month, whereas toenails grow about half as quickly (approx. average a month). Fingernails require three to six months to regrow completely, and toenails require twelve to eighteen months. Actual growth rate is dependent upon age, sex, season, exercise level, diet, and hereditary factors. The longest female<unk>  known ever to have existed measured a total of 8.65 m (28 ft 4.5 in). Contrary to popular belief,<unk>  do not continue to grow after death; the skin dehydrates and tightens, making the<unk>  (and hair) appear to grow. Permeability The<unk> is often considered an impermeable barrier, but this is not true. In fact, it is much more permeable than the skin, and the composition of the<unk> includes 7–12% water. This permeability has implications for penetration by harmful and medicinal substances; in particular cosmetics applied to the<unk>  can pose a risk. Water can penetrate the<unk> as can many other substances including paraquat, a fast acting herbicide that is harmful to humans, urea which is often an ingredient in creams and lotions meant for use on hands and fingers, and several fungicidal agents such as salicylic acid, miconazole branded Monistat, natamycin; and sodium hypochlorite which is the active ingredient in common household bleach (but usually only in 2–3% concentration).
Nail 
Labdoor
Syringe
Caul
Xilloc
Drustbed
Crown 
Dreamlab