Lecture 1 Principle Skin and Fascia 2020 PDF

SKIN -It covers the body and protect it from the environment. -It is formed of two layers: 1- Epidermis; the superficial layer, consists of stratified squamous epithelium. 2- Dermis; the deep strong connective tissue layer Epidermis: It consists of stratified squamous epithelium - - The epidermis be...

SKIN -It covers the body and protect it from the environment. -It is formed of two layers: 1- Epidermis; the superficial layer, consists of stratified squamous epithelium. 2- Dermis; the deep strong connective tissue layer Epidermis: It consists of stratified squamous epithelium - - The epidermis becomes thicker in areas subjected to pressure like the sole of the foot. - If the epidermis is lost over an area of skin, an ulcer is formed. - Dermis: Is a strong connective tissue layer rich in blood vessels, lymphatics and sensory nerve endings. - Skin Lines: Flexure lines (Skin creases): They are folds of the skin over joints. Papillary ridges: They are confined to palms and soles Skin creases& papillary ridges Wrinkle& Langer lines 3-Wrinkle lines: On the face they are known as lines of expression which become permanent with aging due to loss of skin elasticity. 4-Langer (tension) lines They represent the orientation of collagen in the dermis. Surgical incisions made parallel to them heal with a minimum of scar tissue. : Function of the skin Protection of the deep structures of the body against micro-organism and external injury Prevent fluid loss Regulation of body temperature by secretion of sweet gland Sensation (pain,touch,tempretuer)by nerve ending Moistening of skin by secretion of fat from sebaceous glands, Skin appendages Include: 1-Nails 2-Hairs 3-Sebaceous glands 4-Sweat glands Nails Nails are keratinized plates on the dorsal surfaces of the tips of the fingers and toes. Root of the nail is the proximal edge of the plate. Nail folds are folds of skin that surround the nail except the distal edge of the plate. Nail bed is the surface of skin covered by the nail. Hairs and Hair follicles -  Hair is a derivative of the epidermis which consists of two distinct parts: the hair follicle and the hair shaft.  Hair follicle is a sac from which a hair grows  Hair shaft consists of a cortex and cuticle cells, and a medulla for some types of hairs.  Hair bulb is the concave base of the hair follicle, and the concavity is occupied by vascular hair papilla.. Sites with no hair Lips. The palms of the hands. The sides of the fingers. The glans penis and clitoris. The labia minora and the internal surface of the labia majora. The soles and sides of the feet and the sides of the toes. Glands: ∑ Sweat glands: Long tubular glands that lie coiled in the depth of the dermis. ∑Sebaceous glands: Occur only in hairy skin. Each gland is a cluster of large pale cells like a bunch of grapes which secrete oily material (sebum. ) If they become chocked they produce blackheads. If they are infected they produce acne. Sites with no sweet glands The red margins of the lips. The nail beds. The glans penis and clitoris. FASCIAE : SUPERFICIAL FASCIA DEEP FASCIA........... 7-16 Fasciae 1. T h e s u p e r f i c i a l f a s ci a Mixture of loose areolar and adipose tissue that unites the dermis of the skin to the underlying d e e p f a s c i a e. 2. The deep fascia: - A membranous layer of C.T. invests the muscles and other deep structures In the scalp, the back of the neck, the palms of the hands, and the soles of the feet, it contains numerous bundles of collagen fibers that hold the skin firmly to the deeper structures. Areas in the body the superficial fascia without fat In the eyelids, auricle of the ear, penis and scrotum, and clitoris, Functions of superficial fascia It gives certain parts of the body their specific contour as in buttock and breast. It acts as heat insulator by prevention of excess heat loss. It is a source of energy. It acts as a medium for the passage of cutaneous nerves and vessels. 2. The deep fascia: - A membranous layer of C.T. invests the muscles and other deep structures -In certain places the deep fascia forms well-defined layers eg. -In the neck: Play an important role in determining the path taken by pathogenic organisms during the spread of infection. - In the thorax and abdomen: A thin film of areolar tissue covering the muscles and aponeurosis. - In the limbs: Forms a definite sheath around the muscles and other structures, holding them in place. - In region of joints: Thickened to form restraining band called retinacula which holds the underlying tendon in place It forms retinacula to hold the long tendons Functions of the deep fascia: It holds underlying tendons in position or serves as pulleys around which the tendons may move. It invests the deep structures to bone. It gives the origin and insertion of some muscles. It sends septa to bone forming compartments. It forms retinacula to hold the long tendons. It protects palm and sole by forming palmar and plantar aponeuroses