Section 2 -- Skin and Nail

Question 1

Free Edge of Nail

Answer 1

The nail plate leaves the end of the finger and forms a projection that is called the free edge.

Question 2

Hyponychium

Answer 2

the thin band of thickened epidermis beneath the free edge of the distal nail plate.

The junction of the nail bed (sterile matrix) and the fingertip skin, beneath the distal free margin of the nail. It consists of a keratinous plug that prevents debris from getting under the nail plate. The hyponychium also contains large numbers of leukocytes and lymphocytes and is the first barrier of defense to prevent bacteria and fungi from invading the subungual area.

The hyponychium is the area between the free edge of the nail plate and the skin of the fingertip. It also provides a waterproof barrier.

Question 3

Hyponychium singular

Answer 3

(hyponychia)

Question 4

Nail Plate

Answer 4

visible part of the nail, composed of a very hard protein, keratin

The nail plate is the actual fingernail, and it’s made of translucent keratin. The pinkish appearance of the nail comes from the blood vessels that are underneath it. The underside of the nail plate has grooves that run along the length of the nail and help anchor it to the nail bed.

Question 5

Eponychium singular

Answer 5

(eponychia)

Question 6

Eponychium

Answer 6

The eponychium is more commonly known as the cuticle. The cuticle is situated between the skin of the finger and the nail plate. It fuses these structures together and provides a waterproof barrier

Question 7

Paronychium

Answer 7

Soft tissue around the nail and the nail folds comprises the paronychium. Helps keep dirt, bacteria and other organisms from getting underneath the nail and causing an infection.

The paronychium is the skin that overlaps onto the sides of the nail plate, also known as the paronychial edge. The paronychium is the site of hangnails, ingrown nails, and paronychia, a skin infection.

Question 8

When the paronychium becomes infected, the condition is called?

Answer 8

paronychia

Question 9

Lanula

Answer 9

the white opaque crescent area located at the proximal end of the nail, it is white because the blood vessels are deeper to nourish the matrix

Question 10

Lanula singular

Answer 10

(lunule)

Question 11

Root of Nail

Answer 11

The thickened proximal portion of the nail bed encompasses the nail root dorsally and ventrally and is called the matrix.

The root of the nail is also known as the germinal matrix. Its edge appears as a white crescent, known as the lunula. The root portion of this nail lies below the skin, underneath the nail, and extends several millimeters into the finger. It produces most of the volume of the nail and the nail bed.

Question 12

Nail Matrix

Answer 12

The thickened proximal portion of the nail bed encompasses the nail root dorsally and ventrally and is called the matrix. The matrix is where brand, spankin’ new keratinized cells – which will eventually become the nail plate – are formed.

The root of the nail is also known as the germinal matrix. Its edge appears as a white crescent, known as the lunula. The root portion of this nail lies below the skin, underneath the nail, and extends several millimeters into the finger. It produces most of the volume of the nail and the nail bed.

Question 13

Nail Bed

Answer 13

a modification of the dermis to which the nail is firmly attached, nail takes on the pinkish color from the highly vascular tissue

The nail bed is also referred to as the sterile matrix. It extends from the edge of the nail root, or lunula, to the hyponychium. The nail bed contains blood vessels, nerves, and melanocytes that produce melanin. As the root grows the nail, the nail streams down along the nail bed and adds material to the underside of the nail to make it thicker. When the nail grows properly, the nail bed is smooth, but if the nail doesn’t grow correctly, the nail may split or develop ridges that aren’t cosmetically attractive.

Question 14

Sulcus

Answer 14

the groove between the skin and nail on either side of the nail

Question 15

Sulcus singular

Answer 15

(Sulci)

Question 16

Epidermis

Describe
Functions
Where is it thickest?

Answer 16

The epidermis is the outermost of the three layers that make up the skin

Nil blood vessels, few nerve endings. Five distinct layers, each giving rise to the next layer. Covering the epidermis is layer of cells that migrate from dermis.

Functions: mechanical barrier against bacteria and abrasion.

Thickest on palms and soles.

Question 17

Keratinization

Answer 17

28 day process of cells migrating from basal layer (dermis) to die on horny/outer layer

Question 18

Dermis

What is it made of and to what end?
What does it contain?

Answer 18

layer of skin between the epidermis and subcutaneous tissues

Collagen/elastin fibres for skin strength and pliability.

The dermis is a thicker skin layer and contains nerve fibres, blood and lymphatic vessels, sweat glands, sebaceous glands and hair follicles.

Question 19

Subcutaenous

Location
Describe its qualities on the sole of the foot
Where is it most prominent on the dorsum and why?
What does this skin layer contain?
Describe its qualities on the dorsum of the foot
This leads to?

Answer 19

Layer of adipose tissue below the dermis.

Fibrous and tough on the sole of the foot, especially on the heel. The plantar surface of each foot has a thicker layer of subcutaneous tissue.

“Fat pads” can be found over the metatarsal heads and the calcaneus for the purposes of shock absorption.

The subcutaneous tissue or hypodermis contains the large blood vessels, lymph vessels, and the nerves endings of the skin.

The dorsum of the foot has very little subcutaneous fat and the skin tends to be thinner, making it more prone to injury.