Nail Anatomy & Disorders

Understanding nail anatomy is fundamental for any cosmetologist. Proper identification of nail structures helps you perform services safely and recognize conditions that require medical attention. This section covers 10% of the NIC Cosmetology Exam.

The Nail Unit

The nail unit is the complete structure of the nail, composed of several interconnected parts that work together. Understanding each component helps you provide better nail services and identify problems early.

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Primary Nail Structures

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Nail Matrix

The nail matrix (also called the germinal matrix or matrix unguis) is the most critical part of the nail unit. It is the active tissue responsible for generating nail cells.

Key Points:

• Located beneath the proximal nail fold
• Contains melanocytes (cells that produce color)
• Determines the thickness and shape of the nail plate
• Damage to the matrix can cause permanent nail deformity
• Cells harden (keratinize) as they move outward to form the nail plate

Exam Tip: The matrix is the "factory" that produces the nail. If asked what determines nail thickness, the answer is the matrix.

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Nail Plate

The nail plate is the actual nail - the hard, visible surface we polish and shape. It consists of approximately 196 rows of compacted, dead keratin cells called onychocytes.

Characteristics:

• Composed of hard keratin (same protein as hair)
• Transparent - the pink color comes from blood vessels in the nail bed
• Contains no nerves or blood vessels (why cutting nails is painless)
• Attached to the nail bed by specialized ligaments
• Average thickness is 0.5mm for fingernails

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Nail Bed

The nail bed is the skin beneath the nail plate. It is rich in blood vessels and provides:

• Nourishment to the entire nail unit
• Support for the nail plate
• The pink color visible through the transparent nail plate

Key Point: The nail bed begins just distal to (beyond) the lunula and extends to the hyponychium.

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Lunula

The lunula (Latin for "small moon") is the whitish, crescent-shaped area at the base of the nail plate.

Important Facts:

• The lunula is the visible part of the nail matrix
• Most visible on the thumb
• May not be visible on the pinky finger
• The white color is due to nail cells still containing nuclei
• Damage to the lunula can affect nail growth

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Hyponychium

The hyponychium (informally called the "quick") is the epithelium (skin) located beneath the free edge of the nail plate where it meets the fingertip.

Function:

• Creates a seal that protects the nail bed
• Prevents bacteria and pathogens from entering
• Sensitive area - cutting into it causes pain and bleeding

Exam Tip: The hyponychium is often called the "quick" because cutting into it is painful ("cut to the quick").

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Eponychium vs. Cuticle

Many people confuse these terms, but they are different:

Important: Cosmetologists are permitted to push back the eponychium and remove excess cuticle. However, cutting living tissue is prohibited in most states.

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Nail Growth

Understanding nail growth helps you schedule services and educate clients:

Factors Affecting Nail Growth:

Increases Growth:

• Youth (children grow nails faster)
• Pregnancy
• Summer/warm weather
• Good nutrition
• Minor trauma (biting stimulates growth)

Decreases Growth:

• Aging
• Poor circulation
• Illness or fever
• Malnutrition
• Cold weather
• Certain medications

Common Nail Disorders (Onychosis)

Onychosis is the medical term for any disease, disorder, or deformity of the nails. Understanding these conditions helps you determine when to perform services and when to refer clients to a physician.

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Disorders You CAN Service (Non-Infectious)

These conditions are not contagious and do not contraindicate nail services:

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Conditions Requiring Medical Referral (DO NOT SERVICE)

These conditions are contraindications - do not perform services and refer the client to a physician:

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When NOT to Perform Nail Services

Always decline services and refer to a physician when the client presents with:

• Any sign of infection (redness, swelling, pus, warmth)
• Inflammation around or under the nail
• Open wounds or cuts near the nail area
• Fungal infections (thick, discolored, crumbly nails)
• Any unusual growths near the nails
• Signs of psoriasis or eczema on hands/feet
• Unexplained changes in nail color or texture
• Dark streaks in the nail plate (possible melanoma)
• Diabetic clients with any foot concerns

Exam Tip: When in doubt, do not perform the service. Your scope of practice does not include diagnosing or treating nail diseases.

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Protecting Yourself and Clients

To prevent the spread of nail disorders:

• Always sanitize and disinfect implements properly
• Use disposable files and buffers when possible
• Never use implements that have contacted infected nails on other clients
• Wear gloves during disinfection procedures
• Keep your workstation clean and organized
• Do not perform services on yourself if you have an infection