Dr. Rashmi Malhotra Associate Professor Skin and Fascia Dr. Rashmi Malhotra Associate Professor

OBJECTIVES Describe layers of skin. Enlist the functions of skin. Define appendages of skin. Define Fascia. Differentiate between Superficial and Deep Fascia. Applied Anatomy

Tissues of the body The tissue: is a group of cells which perform a specific function There are four basic tissues: 1.Epithelium 2.Connective tissue 3.Muscular tissue 4.Nervous tissue

Skin

IMPORTANCE OF SKIN Normal skin is a very complex organ The skin is one of the largest organs of the body: 76oo sq cm

FUNCTIONS OF THE SKIN 1-Protection continuous and covers the body as well as protects the deep tissues  abrasion, invasion, water loss, UV protection 2-Vitamin D synthesis  epidermal keratinocytes when exposed to UV light  helps maintain health of skeleton by increasing absorption of Ca2+

3-Sensation  receptors for heat, cold, touch, pressure, vibration and pain 4- Thermoregulation  thermo receptors and sweat glands  hypothalamus controls cutaneous arteries and sweat glands to retain or dissipate heat

5- Excretion through the secretion of sweat. 6- Psychological and social functions  appearance and social acceptance  facial expression and nonverbal communication

Keratinized stratified squamous epithelium devoid of blood vessels epidermis Dermis Connective tissue containing (bl. v. lymph v., sensory nerve endings, smooth m, hair follicles, sweat and sebaceous glands) In its deep part the collagen bundles are arranged in parallel rows

The Epidermis

Cells of the Epidermis Keratinocytes (90%)- waterproofs & protects skin, nails, hair, stratum corneum Melanocytes (8%)- produce melanin Merkel Cells- slow mechanoreceptors Langerhans’ Cells- immunological defense

Layers of the Epidermis Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale- (Germinativum)

Layers of the Epidermis

Epidermis Thickness is increased: Why? The epidermis is generally thin except in : The palms of the hand. The soles of the feet. Why? To protect these parts and withstand friction, wear and tear that occurs in these regions.

The Dermis Dermis

Layers of the Dermis papillary dermis reticular dermis

Components of the Dermis a. Cellular Fibroblasts (synthesize collagen, elastin, and reticulin), histiocytes, endothelial cells, perivascular macrophages and dendritic cells, mast cells, smooth muscle, and cells of peripheral nerves b. Fibrous Collagen & reticulin - provide tensile strength Elastic fibers- provide for restoration of shape after a deformation c. Ground substance glycosaminoglycans: hyaluronic acid, chondroitin sulfate, and dermatan sulfate.

The Hypodermis Hypodermis This layer contains adipose tissue and serves to attach the dermis to its underlying tissues.

Lines of cleavage (langer’s lines): The collagen fibers, arranged in parallel rows, called: Lines of cleavage (langer’s lines): The direction of the rows of collagen fibers in the dermis: It runs Longitudinally in the limbs. Circumferentially in the neck and the trunk.

Lines of cleavage These lines are important to determine the direction for an incision (cut) during a surgery to avoid obvious scars.

A surgical incision along or between these lines causes the minimum disruption of collagen so that the wound heals with a small scar. Conversely, an incision made across the rows of collagen makes a disruption resulting in the massive production of fresh collagen and the formation of a broad scar.

Skin creases Folded skin over the joints. Skin is thin and is firmly adherent to underlying structures.

Skin Color Some variations in human skin color Sub-Saharan African, Indian, Southern European, Northwest European

Skin Color Due to Melanin, a pigment in the epidermis and Carotene, Melanin is synthesized in cells called Melanocytes (found in basal layer). Number of Melanocytes is essentially the same in all races. The differences in skin color is due to the amount of pigment the melanocytes produce.

Skin Color Conditions Cyanotic Jaundice Erythema Pallor

Skin/Hair Color: Pigmentation Pigmentation levels usually increase with age. - exception: premature graying Normal pigmentation may be altered by genetic defects or by acquired diseases. -Hyperpigmentation- age spots -Hypopigmentation- vitiligo, albinism

Skin/Hair Color: Pigmentation External agents can also alter skin color. lightening agents carotene dyes Some internal compounds--such as the byproducts of hemoglobin metabolism--may color the skin.                             

SKIN IN ANAEMIA

CHICKEN POX

SKIN ERUPTIONS

ACNE

Skin infections Pathogenic organisms can enter to the tissue through : Nail Folds Hair Follicles Sebaceous Glands Staphylococcus: A type of bacteria that causes skin infections.

Ring worm

Skin Cancer Malignant melanoma 2% of all cancers Risks: Skin type Sun exposure Family history Age Immunological status                              Normal mole Melanoma A= asymmetry B= border C= color D= diameter

Skin Cancers

The appendages of the skin Nails Hairs Sebaceous glands Sweat glands

Nails A nail is a flat horny plate on the dorsal surface of tips of the fingers and toes It has: Root: proximal edge (part embedded in skin) body: exposed part & has a free distal edge Nail fold: folds of skin surround and overlap the nail Nail bed is very vascular causing pink color of the nail The germinative zone lies beneath the root& is responsible for growth of nail

Hair Cover whole surface of the body except some areas as lips, palms, soles, some genital areas

Hair Hair follicles: invaginations of the epidermis into the dermis, the hair grows out of these follicles (hair shaft). Hair bulb: the expanded extremity of the follicle, concaved at the end (located deep in the dermis). Hair papilla: a vascular connective tissue that occupies the concavity of the bulb.

Arrector Pilli muscle A band of smooth muscle connects the undersurface of the follicle to the superficial part of the dermis. It is innervated by sympathetic nerve fibers. It is involuntary.

Arrector Pilli muscle Functions: Its contraction causes the hair to move into a more vertical position. It compresses the sebaceous gland and causes it to extrude sebum.

Sebaceous glands Function It secrets sebum to oil (lubricate) hair and skin. Sebum An oily material that keeps the flexibility of the hair and oils the epidermis around the mouth of the follicle.

Sebaceous cyst It occurs because of the obstruction (blocking) of the sebaceous duct.

Sweat glands long tubular glands with deep coiled part. All over the body except red margins of lips, nail beds, glans penis and clitoris. The most deeply penetrated structure.

Skin burns Superficial Deep Heals rapidly from the edges,. Heals quickly. Doesn’t need a skin graft. Heals slowly from the edges. Usually needs skin grafting.

Burns What to Do: Seek Medical Help Immediately If: You think your child has a second- or third-degree burn. The burned area is large, even if it seems like a minor burn. For any burn that appears to cover more than 15% to 20% of the body, call for medical assistance. And don't use wet compresses because they can cause the child's body temperature to drop. Instead, cover the area with a clean, soft cloth or towel. The burn comes from a fire, an electrical wire or socket, or chemicals. The burn is on the face, scalp, hands, joint surfaces, or genitals. The burn looks infected (with swelling, pus, increasing redness, or red streaking of the skin near the wound). For First-Degree Burns: Remove clothing from the burned area immediately. Run cool (not cold) water over the burned area (if water isn't available, any cold, drinkable fluid can be used) or hold a clean, cold compress on the burn until pain subsides (do not use ice, as it may cause the burn to take longer to heal). Do not apply butter, grease, powder, or any other remedies to the burn, as these increase the risk of infection. If the burned area is small, loosely cover it with a sterile gauze pad or bandage. Give your child acetaminophen or ibuprofen for pain. If the area affected is small (the size of a quarter or smaller), keep the area clean and continue to use cool compresses and a loose dressing over the next 24 hours. You can also apply antibiotic cream two to three times a day, although this isn't absolutely necessary. For Second- and Third-Degree Burns: Seek emergency medical care, then follow these steps until medical personnel arrive: Keep your child lying down with the burned area elevated. Follow the instructions for first-degree burns. Remove all jewelry and clothing from around the burn (in case there's any swelling after the injury), except for clothing that's stuck to the skin. If you're having difficulty removing clothing, you may need to cut it off or wait until medical assistance arrives. Do not break any blisters. Put wet, sterile bandages on the burned area until help arrives.

Clinical notes Graft is transferring tissue from one site to another. Skin graft is needed when the skin is damaged ( usually by deep burning )

Split thickness grafting Full thickness grafting Clinical notes Skin Graft Split thickness grafting Full thickness grafting Transferring both epidermis and dermis. Transferring epidermis only

Fascia

Collection of connective tissue Fascia Collection of connective tissue Superficial fascia Deep fascia

Superficial fascia

Deep Fascia

Superficial fascia Superficial fascia: Functions: Loose, mixture of adipose and loose areolar tissues. It unites the skin to the underlying structures. It is dense in some places as scalp, palm of hand and sole of foot and contains collagen bundles It is thin in the eyelids, auricle, scrotum (devoid of adipose tissue). Functions: Facilitates movement of skin over underlying structures. Passage for cutaneous vessels, nerves. Protects the body against heat loss.

Superficial fascia

Deep fascia It is more dense than superficial fascia Collagenous bundles are more compact and more regularly arranged It is usually present in the form of membranes

Examples of deep fascia Intermuscular septa lie between muscles dividing the limb into compartments

Examples of deep fascia B. Investing fascia Covers the surfaces of muscles In the neck: it forms well-defined layers, bounds fascial spaces so limits spread of infection or determine the path of infection In the abdomen: it is thin In the limbs: forms a definite sheath around the muscles

Examples of deep fascia C. Retinacula Localized thickening of deep fascia around joints, hold the tendons in place, prevent bowstringing of tendons

Thank you