Nail structure

• Anatomy and physiology
• Further Education (Key Stage 5)

Nail structure

Aims

To re-cap and review the structure and functions of the nail.

To understand nail diseases and disorders.

Outcomes

Label a cross section of the nail.

Identify the structures which make up the nail.

Identify nail diseases and disorders and understand how to proceed with treatment.

KEY WORDS: Paronychia, whitlow, beau's lines, hangnail, corrugations, furrows, leuconychia, onychogryphosis, onychorrhexis, onychauxis, onychia

00:00

What is the name of the structure which protects the nail bed?

1. Nail plate
2. Eponychium
3. Perionychium
4. Nail wall

00:47

What does the acronym STOP mean

01:35

Which part of the nail is the free edge?

01:59

What is C?

02:02

State the function of keratin

Part of the nail that covers the nail bed. 

Part of the nail which grows beyond the fingertip 

Part of the nail where cells divide by mitosis.

Covered by the nail plate and contains sensory nerve endings and blood vessels.

Overlapping skin at the bottom of the nail plate

Parts of the nail you can see

1. Nail plate – the most recognizable part that is thin, translucent, hard and constructed in

about 100 layers.

2. Free edge – the part not attached to the skin and can extend beyond fingertip

3. Cuticle – small portion of skin that extends over nail plate

4. Lunula – the “half moon” at the base of the nail plate (considered part of matrix)

5. Nail grooves – tracks on each side of the nail plate

6. Nail walls – skin folds beside the nail grooves

7. Eponychium – excess cuticle that overlaps onto the base of the nail

8. Perionychium – cuticle that overlaps onto the sides of the nail plate

9. Hyponychium – a layer of skin cells growing on top of the fingertips (attached to

underside of free edge)

Parts of the nail you cannot see

1. Nail root – portion of nail plate hidden under fold of skin (mantle) at base of nail plate

2. Nail bed – portion of the skin to which the nail plate is attached (contains many

nerve endings)

3. Epithelium – thin layer of skin cells between nail bed and nail plate

4. Matrix – part of the nail bed that extends below the nail root (helps produce the nail)

The size and shape of the matrix determines the thickness and shape of the natural nail

5. Mantle – pocket-like fold of skin that holds the root and the matrix

Eponychium, perionychium and hyponychium act as watertight seals.

1. Provide a protective barrier on nail plate

2. Prevent entrance of dirt and bacteria

3. Damaging seals can lead to infections and disease.

Onychomycosis Is a fungal infection of the nail. Symptoms may include white or yellow nail discoloration, thickening of the nail, and separation of the nail from the nail bed.

Onychogryphosis is a nail disease that causes one side of the nail to grow faster than the other. The nickname for this disease is ram's horn nails because the nails are thick and curvy, like horns or claws. It mostly affects the toes — specifically the big toes.

Onychia- General term to describe any disease of the nail but more specifically refers to inflammation of the nail folds (surrounding tissue of the nail plate) of the nail with formation of pus and shedding of the nail.

Onychophagy – The technical nail for nail biting in which the free edge,nail plate and cuticle are bitten to leave the hyponychium exposed.

Onycholysis- This is separation or loosening of part or all of a nail from its bed. 

Onychorrhexis- This term is given to dry, brittle nails that may result from hypothyroidism, anaemia, anorexia nervosa or bulimia, or after oral retinoid therapy

Leukonychia- (white spots) caused by the separation of the nail plate layers

A white spot is a sign on trauma, e.g. knocking a nail. They are NOT caused by a lack of calcium.

Paronychia – Inflammation of skin surrounding the nail. The skin may be swollen, pus may also be present.

Beau's lines - Lines or deep grooves that run across the nail plate.  May be caused by an injury to the nail.

Corrugations - Long ridges that run either lengthwise or across the nail; some lengthwise ridges are normal in adult nails, and they increase with age; lengthwise ridges can also be caused by conditions such as psoriasis, poor circulation and frostbite.  Also known as furrows

Eggshell nails - Flaky and split nails, particularly at the ends, hence the name "eggshell."  You can see the blood circulation closer to the surface of the nail plate that has thinned, hence the blue colour.

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