Chapter 9

Nail Structure & Growth

Learning Objectives

• Describe the characteristics of normal, healthy nails.• Describe the nine basic parts of the nail unit. • Discuss how nails grow.

Introduction

• You cannot perform professional nail services without understanding the structure and growth of the natural nail.

• Specializing in nail services will add extra revenue to your pocket and give you another way to express your creative talent.

• By becoming familiar with the anatomy and physiology of the nail, you will be able to better recognize abnormalities and disorders that can and cannot service in a salon.

Distinguish the Structure of the Natural Nail

The Natural Nail• Onyx – the technical term for natural nail• The onyx is the hard protective plate

composed mainly of keratin, the fiber-shaped protein found in skin and hair.

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• A normal, healthy nail is firm but flexible.• Surface is shiny, smooth, unspotted.• Whitish and translucent in appearance, with the

pinkish color of the nail bed below showing through. • Water content is between 15 and 25 percent

Distinguish the Structure of the Natural Nail (continued)

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Identify Nail Anatomy

• Nail plate (nail body)

• Free edge

• Nail bed

• Matrix

• Lunula

• Cuticle

• Eponychium

• Perionychium

• Hyponychium

• Specialized ligaments

• Nail folds

• Sidewall

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Identify Nail Anatomy (continued)

Nail Plate

• The most visible and functional part of the nail unit

• Rests on/slides across nail bed

• Formed by matrix cells

• Constructed in layers

• Free edge extends over tips of finger or toe

Nail Bed

• Skin supporting nail plate as it grows toward free edge

• Extends from lunula to just before free edge

• Attached to nail plate by a thin layer of tissue called bed epithelium

• Supplied with many blood vessels

Matrix

• Where nail plate cells are formed

• Composed of matrix cells that produce nail plate

• Contains nerves, lymph, and blood vessels to nourish nails

• Extends from under nail fold at base of nail plate

Lunula

• Visible part of matrix

• Whitish, half-moon shape at base of nail

• Color caused by reflection of light off matrix surface

• Some are hidden under eponychium

Cuticle

• Dead, colorless tissue attached to nail plate from underside of skin that lies above natural nail plate

• Sticks tight to the nail plate; difficult to remove from nail plate

• Seals the space between the natural nail plate and living skin above to prevent entry of foreign material and microorganisms

Eponychium

• The living skin at base of nail plate covering matrix

• Often mistaken for cuticle

• Cannot be trimmed or cut by nail technician

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Perionychium

• The living skin bordering the root and sides of a fingernail or toenail

Hyponychium

• The slightly thickened skin that lies between the fingertip and the free edge

• Protective barrier that seals the free edge, preventing microorganisms from invading and infecting the nail bed

Specialized Ligaments

• Tough bands of fibrous tissue that connect bones or hold an organ in place

• Attach the nail bed and matrix bed to underlying bone

• Located at base of matrix and around edges of nail bed

Nail Folds

• Folds of normal skin surrounding nail plate

• Form nail grooves or furrow on each side of the nail

Sidewall

• Also known as the lateral nail fold • The fold of skin overlapping the side of the nail

Discuss Nail Growth

• Growth is affected by nutrition, general health, and exercise.

• Nails grow forward, starting at matrix and extending over fingertip.

• Nails grow in a variety of shapes.• Average growth is 1/8 to 1/10 of an inch per

month.• Growth is faster in summer than winter.• Children’s nails grow faster than adults’ nails.

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Discuss Nail Growth (continued)

Nail Malformation

• This can be a temporary or permanent condition caused by disease, injury, or infection that has affected the matrix.

• The shape or thickness of the nail plate can appear altered or deformed.

• Nail malformation can cause a person to shed a nail. • Replacement of a natural fingernail takes

4 to 6 months. • Replacement of a toenail takes 9 to 12 months.

Aging

• As a person ages, parts of the nail matrix begin to permanently slow down production, causing the plate to develop a series of narrow grooves running down the length of the plate.

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Know Your Nails

• Many cosmetologists are interested in nails because of the creative opportunities they present.

• As with every other area of cosmetology, this creativity must be grounded in a full awareness of the structure and physiology of the nails and the surrounding tissue.

Summary and Review

• Well-manicured nails, whether natural or artificially applied, have always been recognized as an indication of good grooming; nails originate in the epidermal layer of the skin and, like hair, their condition is dependent upon the individual’s overall health.

• A balanced diet filled with the daily required vitamins and nutrients will help produce healthy, disorder-free nails.

• Remember that your creativity in providing quality nail services must be grounded in a thorough knowledge and awareness of the structure and physiology of the nails.

Chapter Review Questions

1. What is the technical term for the natural nail?

2. What is the major protein that makes up the natural nail?

3. Describe the appearance of a normal, healthy nail.

4. Name the basic parts of the nail unit.

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5. Explain the difference between the nail plate and the nail bed.

6. What part of the nail unit contains the nerves, lymph, and blood vessels?

7. What is the difference between the cuticle and the eponychium?

Chapter Review Questions (continued)

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8. Why are cosmetologists not allowed to cut the skin around the base of the nail plate, even if the client requests this during the service?

9. What can affect the growth of the nail plate?

Chapter Review Questions (continued)