Nail is very important but vital accessory structure of skin. It is found over dorsal surface of distal ends of fingers of hands and also on dorsal surface of distal ends of toe fingers that is fingers of feet.
Nail is nothing live but dead tissue. It is made up of dead, keratinized epidermal cells which have become hard and are tightly packed in plates. Nails play a very vital but important role in our day to day life. They help us in grasping and plucking off those tiny things from surface which are otherwise difficult to get hold of. For example those tiny things which are glued to surface nails help in scratching them off from glued surface. They also help in protecting finger tips of digits of hands and feet from injuries and change in colour, shape, form and rigidity or hardness of nail also give indications of various diseases occurring inside the body.
So this was brief on what importance and role of nail in our day to day life. But the topic of this article is “Do you know everything about structure of nail?” Do not worry, if question is here, then answers to all your questions regarding structure of nail are also here. So as regards to structure of nail it is formed of plates of hard, dead keratinized epidermal cells which are tightly packed relative to each other. Nails on its own have no colour. Its light pinkish colour in state of health is due to blood flowing through blood capillaries underneath the nail body which give it its pink colour.
Structure of nail is as follow- it consists of three parts-
1. Nail body.
2. Free edge.
3. Nail root.
1. Nail body-
Nail body also known as nail plate forms the major part of nail. It is light pinkish visible portion of nail. It is light pinkish in colour in health whereas in diseased state nail body changes its colour to yellow, blue or sometimes grayish to blackish. Light pinkish colour nail body is indicative of healthy nails. Now, question is why this nail body appears light pinkish? The answer to which I have already answered above in this article. The light pinkish colour of nail body is due to blood capillaries underneath the nail body which give nail body its light pinkish appearance. It is the blood capillaries which give nail body its light pinkish appearance; on its own nail body has no colour of its own, it is made of dead keratinized epidermal cells which have no colour of their own.
So this was about color appearance of nail body, in respect of structural elements nail body is made of plates of dead, keratinized epidermal cells which are tightly packed or placed relative to each other in different plates of nail body. The keratinized cells of nail body are much harder and do not shed. Nail body is attached below to the epithelium, below epithelium lies dermis which contains blood capillaries which give nail body its pinkish colour. Lunula is half moon shaped structure found in proximal portion of nail body which is white in colour. Now why this area is white in colour when rest of nail body is light pinkish in colour, the reason behind this is that epithelium which lies in this region is much thicker than nail body. We know the epithelial keratinized cells in nail body are tightly packed which make nail thick but this portion is much thicker than nail body which does not let blood vessels below lunula show their colour on this portion of nail body due to thickness of this region which does not let show colour of blood vessels show on its surface.
2. Free edge-
Free edge of nail is distal portion of nail which is extended past the distal end of the fingers of hands and toes of feet. Free edge is whitish in colour and it is that portion of nail which you cut with the help of nail cutter. As no dermis or epithelium is attached below the free edge of nail therefore no blood vessels running under free edge, therefore, no pinkish colour of free edge as is found in nail body. Instead it is white in colour.
Hyponychium is thickened region of stratum corneum at proximal border of free edge which seals the nail to finger tip and does not let it slough off. Hyponychium is also known by other name called nail bed. Angle made at hyponychium by fingertip and free edge of nail is the area where dirt or other material that you try to starch off or semi solid material or powdered material in which you have put your hand get collects which is the cause of infection. The only solution to this is, to cut free edge of your nails on timely basis and wash your hands when they get dirty.
3. Nail root-
Nail root is that portion of nail which lies proximal to nail body. Yes you get it right; nail root is the proximal portion of nail which is enclosed in a fold of skin. Narrow band of epidermis which extends from and attached to lateral borders and proximal border of nail that is layer of epidermis which is attached to lateral and proximal end of nail is called the eponychium. Eponychium is also known by other name called cuticle.
This was all about structure of nail, only thing which is left to discuss and which is responsible for nail growth. Yes you get it right that is the mechanism of nail growth. How nail growth occurs? Proximal area of epithelium deep below nail root called nail matrix where mitosis occurs that is cells divide by process of mitosis. Now how nail matrix helps in nail growth. Nail growth occurs by transformation of superficial cells of nail matrix produced by process of mitosis into nail cells. So this was all about structure of nail.
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