Anatomy of Hair and Nail Structures

Vocabulary flashcards defining the anatomical structures of the hair follicle and nail as illustrated in the study diagrams.

Anatomy of Hair and Nail Structures

Diagram illustrating the key components of the hair follicle and hair shaft (A) as well as the structure of the nail (B).

Hair shaft

The portion of the hair that projects beyond the surface of the skin.

Sebaceous gland

An exocrine gland attached to the hair follicle that secretes sebum into the follicle.

Arrector pili muscle

A smooth muscle attached to the hair follicle that pulls the hair upright when contracted.

Hair root

The portion of the hair embedded within the follicle beneath the skin surface.

Connective tissue sheath

The outer connective tissue layer that surrounds and supports the hair follicle.

Hair follicle

The invagination of the skin that surrounds the hair root and gives rise to hair growth.

Hair bulb

The enlarged base of the hair follicle that surrounds the hair papilla.

Hair papilla

A vascular projection of dermal tissue at the base of the hair bulb that supplies nourishment to the hair.

Eponychium

The narrow band of epidermis extending onto the proximal part of the nail plate.

Proximal nail fold

The fold of skin at the proximal edge of the nail plate.

Lateral nail fold

The skin folds along the side edges of the nail plate.

Lunula

The crescent-shaped, pale area at the base of the nail plate.

Nail plate

The visible, rigid body of the nail resting on the nail bed.

Free edge

The distal portion of the nail plate that extends beyond the tip of the digit.

Nail matrix

The thickened area of epidermal tissue beneath the proximal nail fold where nail growth occurs.

Hyponychium

The region of thickened epidermis under the free edge of the nail plate.

Phalanx

The bone of the digit situated beneath the nail assembly and dermal layers.