Lesson Objectives To state the functions of the nail To identify the anatomical regions of the nail To label a diagram of the nail

The Nail An extension of stratum lucidum of epidermis Composed of flattened cells which undergo keratinisation, giving nail hard appearance Keratin is a protein that makes nail strong but flexible Nutrients to nail are supplied via dermis

Functions of Nail Protective covering at ends of phalangeal joints of fingers and toes Enables us to touch, manipulate small objects and scratch surfaces

Diagram of Nail

Nail Matrix Found below cuticle Living cells are produced here Receives supply of blood which supplies oxygen to nail and is vital to production of new cells

Nail Bed Found below nail plate A continuation of the matrix Part of skin upon which nail plate rests Richly supplied with blood vessels, lymph vessels and nerves from underlying dermis Provides nourishment and protection for nail

Cuticle Fold of overlapping skin that surrounds base of nail Various areas – eponychium, perionychium, hyponychium Protects matrix and provides protective seal against bacteria

Lunula Semi-circular area of nail – called half-moon – that lies between matrix and nail plate Area of nail where cells start to harden Lunula is a bridge between living cells of matrix and dead cells of nail plate

Nail Plate Main visible part of nail which rests on nail bed and ends at free edge Made of layers of translucent, dead, keratinised cells Offers protection for nail bed

Nail Walls Folds of skin overlapping sides of nails Surround three sides of nail and attach to sides of nail plate Protect edges of nail plate from external damage

Nail Grooves Deep ridges under sides of nail Guide nail and help it to grow straight

Free Edge Part of nail plate that extends beyond nail bed Part of nail that is filed and is usually hardest part

Nail Mantle Fold of skin in front of the cuticle which protects the matrix Matrix is where the nail is made It is the only living section of your nail, plus it contains nerves as well as blood vessels to ensure that cell processing can occur

Eponychium The thickened layer of skin surrounding fingernails and toenails Its function is to protect the area between the nail and epidermis from exposure to bacteria

The tissue bordering the root and sides of a fingernail or toenail Perionychium The tissue bordering the root and sides of a fingernail or toenail

Hyponychium Hyponychium is the area of skin between the fingertip and the nail plate Area of skin that provides the fingertip with a waterproof barrier to stop bacteria or debris from going under the nail plate and causing infection or damage

Nail Growth Start to grow on foetus – fourth month Cells divide through a process called mitosis in the matrix As new cells are produced, old cells pushed forward Begin to harden and keratinisation occurs Nail grows moves along the nail grooves Help direct the nail forward

Nail Growth Continued Approximately 6 months from the lunula to the free edge 3 mm per month Toe nails grow slower than finger nails Faster in summer due to UV radiation