Skin and Fasciae PDF

DEPARTMENT OF ANATOMY, PUMS INTRODUCTORY LECTURE SERIES – ANA 211 TOPIC: MUSCLES, BURSAE AND SYNOVIAL SHEATHS BY M. A. AMADI GOAL Introduce the basic structure of the skin as an important organ. LEARNING OBJECTIVES Provide a suitable definition fo...

DEPARTMENT OF ANATOMY, PUMS INTRODUCTORY LECTURE SERIES – ANA 211 TOPIC: MUSCLES, BURSAE AND SYNOVIAL SHEATHS BY M. A. AMADI GOAL Introduce the basic structure of the skin as an important organ. LEARNING OBJECTIVES Provide a suitable definition for the skin Know the principal components Describe the recognized layers of the skin Give a brief account of the microscopic anatomy of the skin Understand the anatomical basis of surgical incisions  The skin is part of the integumentary system of organs  is the largest organ of the human body,  weighing 6- 9kg and measuring about 2 square meters  it forms a protective container for the organs and a barrier between the internal organs, vital body fluids, and the external environment.  Specialized or modified depending on location and use…tongue and vagina. Display clinical evidence of internal disease peau de range in breast cancer. LAYERS OF THE SKIN  Epidermis Five layers  Dermis Two layers  Hypodermis EPIDERMIS Most superficial of the three layers of the skin Thickness varies ,but 0.6-1mm on the average  Multicellular, up to 50 rows of epithelial cells  Normally avascular TTYPES OF CELLS commonly keratinocytes, Merkel cells. dendritic cells (melanocytes and Langerhans' cells)  The keratinocytes, or keratin-forming cells..80% Particularly thick in the palms and soles DERMIS Deeper layer beneath the epidermis thicker than the epidermis portion of skin responsible for tensile strength, elasticity and appearance Arteriovenous anastomosis ,the apparatus for thermoregultion is present n the dermis  it is divided anatomically into two compartments.  The connective tissue component of the dermis  consists of collagen fibers, including reticulin fibers,  and elastic fibers entwined between the collagen fibers. The elastin and collagen fibers are held together by ground substance, a mucopolysaccharide gel Types 1 and 111 collagen form the thick and thin fibers present in the dermis. The cellular elements of the dermis include Mast cells, Fibroblasts,  endothelial cells, vascular smooth muscle cells, specialized myoepithelia cells.  nerve, and hematopoietic cells.  The hematopoietic immune cells include histiocytes (macrophages), lymphocytes, and plasma. Hypodermis (subcutaneous layer) Flexible bridge of areolar connective tissue between skin and underlying bones and muscles.  constitutes the largest volume of fatty tissue in the body  fat cells show varying degrees of thickness  depending on location and use  hypodermis cont’d Fibrous septae, separate he fat cells into chambers called lobules And contain the blood vessels, lymphatics and nerves The blood vessels and the nerves  pass from the underlying tissues to the dermis above To nourish and keep the skin healthy. Appendages – nails, hair, teeth – Exocrine glands - open onto surface of skin e.g. sweat glands, apocrine glands, sebaceous glands. Clinical: Boil – infected sebaceous glands CLINICALS LANGER’S LINES (SKIN TENSON LINES) These are invisible cleavage lines along which surgical cuts or incisions should be made  to ensure best healing. Based on direction of orientation of the underlying collagen fibres. TENSION LINES OF THE SKIN 16 FASCIAE (SUPERFICIAL/DEEP)  FASCIA is a band of connective tissue, primarily collagen, beneath the skin that attaches, stabilizes, encloses, and separates muscles and other internal organs. CLASSIFICATION It is classified by layer, as superficial fascia, deep fascia, and visceral or parietal fascia, or by its function and anatomical location. Like ligaments, aponeuroses and tendons, fascia is oriented in a wavy pattern parallel to the direction of pull. 18  SUPERFICIAL FASCIA is the lowest layer of the skin that blends with the reticular dermis. Is a mixture of loose areolar and adipose connective tissue and is the layer that primarily determines the shape of a body. It surrounds organs, glands, neurovascular bundles and other locations where it fills unoccupied spaces. Superficial fascia is present, but does not contain fat, in the eyelid, ear, scrotum, penis and clitoris. 19  SUPERFICIAL FASCIA  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, penis and clitoris (devoid of adipose tissue). Functions:  Facilitates movement of skin over underlying structures.  Passage for cutaneous vessels, nerves.  Protects the body against heat loss. 20  DEEP FASCIA is a layer of dense fibrous connective tissue that surrounds individual muscles, and also divides groups of muscles into fascial compartments. This layer has a high density of elastin fibre that determines its extensibility or resilience. Examples are fascia lata, fascia cruris, brachial fascia, plantar fascia, thoracolumbar fascia and Buck's fascia. 21 22 23 24  VISCERAL OR SUBSEROUS FASCIA) suspends the organs within their cavities and wraps them in layers of connective tissue membranes. Each of the organs is covered in a double layer sheet of fascia; these layers are separated by a thin serous membrane. The outermost wall of the organ is known as the parietal layer While the fascial directly in contact with the organ is known as the visceral layer 25  VISCERAL OR SUBSEROUS FASCIA) COT’N The organs have specialized names for their visceral fasciae according to the location. In the brain, they are known as meninges - in the heart: pericardium or pericardia (plural) - in the lungs: pleura or pleurae (plural) - in the abdomen: peritonea 26 Visceral fascia is less extensible than superficial fascia. Due to its suspensory role to the organs and the need to maintain its tone consistently. If it is too lax, it contributes to organ prolapse (displacement of a part or organ of the body from its normal position), yet if it is hypertonic, it restricts proper organ motility. 27