Introduction to Human Anatomy PDF

Introduction to Human Anatomy By DR HALA MOHAMED  The human anatomy: is the science of studying the various structures of the human body.  The human body consists of various types of specialized cells and a varying amount of intercellular substance.  The c...

Introduction to Human Anatomy By DR HALA MOHAMED  The human anatomy: is the science of studying the various structures of the human body.  The human body consists of various types of specialized cells and a varying amount of intercellular substance.  The cell: is the basic unit of the human body. Most types of cells tend to occur in groups similar both in appearance and in function. Such organized groups of cells are known as tissues.   Various types of tissues: form a more complex anatomical functional units known as organs which in turns form system.  Studying the structure of the cells is called cytology.  Studying the structure at tissue level is called histology.  Studying the structure of the body systems is called systemic anatomy.  Human anatomy is studied by 2 methods:  1. Regional or topographical anatomy:  The structures of the human body are studied as they lie in the body in relation to each other in different regions.  These regions are :  1-head Neck Chest Trunk Abdomen Pelvis Upper Limb Limbs Lower Limb Sub-regions of the upper limb Sub-regions of the lower limb  2. Systematic anatomy:  In which the various structures of the body are studied as individual systems. Systematic anatomy  The systems are:  1. Osteology: The bony system or skeleton.  2. Syndesmology: Articular systems or joints.  3. Myology: Muscular system  4. Angiology: Heart, blood vessels, lymph vessels and lymph nodes.  5. Neurology: Nervous system and organs of sense.  6. Splanchnology of viscera:  a) Respiratory system.  b) Digestive system.  c) Urogenital system.  d) Ductless or endocrine glands.  Anatomical Position  The person is standing erect  The upper limbs by the sides  The face and palms of hands are directed forward  The lower limbs are together with feet parallel  Anatomical Planes  The median or midsagittal plane is the vertical plane that divides the body into two equal right and left halves.  Sagittal plane: is vertical plane that passes through the body from front to back parallel to the median plane.  Coronal plane: is vertical plane which pass through the body from side to side perpendicular to the median plane.  Horizontal (transverse) plane is parallel to the floor.  Anatomical Terms  Terms of positions  1. Superior or cephalic: The position of the part that is nearer to the head.  2. Inferior or caudal: Nearer to the feet.  3. Anterior (ventral): Nearer to the front of the body.  4. Posterior (dorsal): Nearer to the back.  The median plane: Is an imaginary' plane that divides the body into two equal halves, right and left.  Median structure: The structure, which is dissected by the median plane.  Medial: Nearer to the median plane.  Lateral: Farther away from the median plane.   Superficial: Structure near to the skin.  Deep: Farther away from the skin.   Proximal: Any structure nearer to the root of the limb.  Distal: Any structure away from the root of the limb.  Terms of movements:  Movements occur in joints and described in sagittal or coronal planes.  Flexion: Bending anteriarly. In limbs, it is folding the limb.  Extension: Bending posteriorly. In limbs, it is straightening the limb.  Dorsiflexion: describes flexion at the ankle joint, as occurs when lifting the toes off the ground.  Plantar flexion: turns the foot or toes toward the plantar surface (e.g., when standing on your toes).  lateral flexion: Movement of the trunk in the coronal plane.   Adduction: Bringing the limb near to the median plane.  Abduction: Taking the limb away from the median plane.  Pronation: is the rotational movement of the forearm so that the palm of the hand faces posteriorly.  Supination: is the rotational movement of the forearm so that the palm faces anteriorly.  Eversion: turning the sole laterally.  Inversion: facing the sole medially.  In the hands, abduction of the fingers is the movements, which take the fingers away from the middle finger while adduction is to bring them nearer to the middle finger.  Circumduction: A circular movement which pass through a number of planes. Body structures  Body structures met in dissection: Skin (INTEGUMENT PROPER) Fascia Muscles Bones  The skin:  The skin covers the body surface. It protects the deeper structures and plays an important role in regulation of body temperature.  It consists of a deep layer of a vascular fibrous tissue termed dermis and a superficial avascular layer, which is formed of many layers of cells, termed epidermis.  The skin is wrinkled in some parts of the body as the palms of the hand and sole of the foot to from creases.  Each part of skin is supplied by a specific spinal nerve.  Skin appendages are certain organs of special functions namely:  i) Hair follicles.  ii) Sweat glands and sebaceous glands.  iii) Nails.  Contents of the dermis:  blood vessels,  lymph vessels,  nerve endings,  hair follicles,  glands.  Fascia  1. Superficial Fascia  It is a fibrofatty layer underneath the skin. It forms a network of fibrous tissue, the intersects of which are filled with fat.  It is dense in the scalp, back of the neck, palms of the hands and soles of the feet.  It is very thin over the dorsal aspects of the hands, feet and side and face.  It facilitates the movements of the skin, retains the warmth of the body and gives the body its contour.  Contents of superficial fascia:  (Structures passing through it in their way to or from the skin):  1. Blood vessels.  2. Lymph vessels.  3. Lymph nodes.  4. Nerves.  5. Glands of skin.  6. Roots of hairs.  7. Muscles in certain part of the body like platysma.  2. Deep Fascia:  A thin dense membrane located deep to the superficial fascia. It is loosely attached to the superficial fascia.  It is inelastic, forming sheath for the muscles and preserving the contour of the limb.  The deep fascia sends various intermuscular septa from its deep surface to connect it to the bone. These septa divide the limb into different groups of muscles.  It is thickened in the palm of the hand and sole of the foot.  It is absent in the abdomen allowing it to change its volume during respiration  Forms of deep fascia:  The investing deep fascia  Capsule  (Intermuscular septa) partitions or septa between the muscles Muscles  This includes all the muscles of the body. There are three types of muscular tissue.  Types of muscles:  1. Skeletal or voluntary: They are stripped (striated) and under the control of will. Examples: muscles of limbs.  2. Smooth or involuntary: They are not under the control of will. They are non stripped muscle. Examples: muscles of intestine, uterus and urinary bladder.  3. Cardiac: Involuntary, partially stripped.  The function of all three types of muscles hart is contraction and relaxation.  The skeletal muscles mostly pass from one bone to another across a joint.  By contraction they approximate the sites of attachment.  The cardiac muscle and smooth muscles form the walls of the cavities and tubes.  By contraction they expel their contents.  The skeletal muscle: is formed of:  1. Fleshy part or the belly.  2. Non-fleshy part (tendon), by which the muscle is attached into a bone. It may be cord like, flat band or sheet like aponeurosis.  Muscle attachments: Skeletal muscle is attached by origin and insertion:  a. Origin: It is fixed, less mobile attachment. It is the proximal attachment of limb muscle.  b. Insertion: It is less fixed, more mobile. It is the distal attachement of the limb muscle.  Muscle forms:  Different forms of muscles are present and described according to the direction of their muscle fibers.  1. Strap or parallel muscle fibers: e.g., sartorius.  2. Fusiform: Spindle shaped fleahy belly and terminal tendon e.g., biceps brachia.  3. Triangular: The fibers are convergent e.g., the temporalis.  4. Pennate:  a. Unipenate: When its tendon appears on one side of the fleshy fibers.  b. Bipenate: When the fleshy fibers are attached to the tendons at angles on both sides e.g., the rectus femoris.  c. Multipennate: When muscle has several tendinous elements to which the fleshy fibers reach from several directions e.g., deltoid. Joints  A joint is the articulation between two or more bones.  Classification:  1. Fibrous Joints:  No movement is allowed at this joint.  The two surfaces of the bones are fused together by intervening fibrous tissue.  There are three types of fibrous joints:  1- The sutures of the vault of the skull.  2- Gomphosis: as fixation of the teeth in the alveolar socket.  3- Syndesmoses: where the two bones are connected by ligament or membrane. Example as the interosseous membrane in the forearm or leg.  2. Cartilaginous joints:  A limited amount of movement is allowed.  The opposed bony surface are connected to each other by a cartilage.  There are two types of cartilaginous joint:  a) Primary cartilaginous joints:  The two bones are connected by cartilage that ossifies later on. No movement in this type of joint. Example is the epiphyseal cartilage plate found between the epiphyses and diaphysis of the growing long bones.  b) Secondary Cartilaginous Joints:  The two opposed bony surfaces are covered by a hyaline cartilage and connected together by a disc of fibrocartilage.  In this type of joint little movement is allowed.  This type of joint is found:  a. Between the bodies of the vertebrae.  b. Between the pubic bones.  c. Between the manubrium and body of sternum.  3. Synovial joint:  It is composed of:  a. Bony articular ends, which are usually large and smooth.  b. Articular cartilage covers the articular surface of the ends of bones. Its elasticity is useful for the load distribution.  c. Fibrous articular capsule, connects the two bony ends together. It may be thickened in parts to form  d. Synovial membrane and synovial fluid; the inner surface of the articular fibrous capsule is lined by a synovial membrane. It is a highly vascular membrane which covers all the intracapsular structures except the articular surface. It secretes a small amount of synovial fluid to lubricate the movements and to nourish the articular cartilage.  e. The blood and nerve supply of the synovial joint is conveyed through arteries and nerves that pierce the fibrous capsule.  The Joint Movement and Stability:  Each movement in the joint has its own axis. Some joint has a single axis e.g. elbow. Others may allow movements in more than one axis e.g. the shoulder. The two articular ends are kept close to one another by factors responsible for the joint stability during rest and motion. The range of the movement is limited by certain limiting factors.  The joint stability:  The joint stability is kept by many factors;  1. Adapted articular surfaces.  2. The joint ligaments.  3. The atmospheric pressure.  4. The muscle tension. Bones  Functions of bones:  1. Give the form of the body  2. Protect certain structure e.g. skull protects the brain.  3. Act as levers for the muscles.  4. Formation of blood cells by the bone marrow.  5. Reservoir for calcium.  A- Types of bones according to general shape  1. Long: It is made up of an elongated tubular shaft and two enlarged ends. It forms levers e.g. bones of the limbs.  2. Short small: Strengthen an area of skeleton with limited movement e.g. carpal and tarsal bones.  3. Flat: It protects certain structure e.g. bones of skull or provides a wide surface for muscular attachment e.g. scapula.  4. Irregular: Have a variable shape e.g. hipbone.  5. Pneumatic: The central part of the bone is absorbed. It is replaced by air-filled spaces e.g. air sinuses.  6. sesamoid bone: as patella Types of bones  B- Types of bones according to Structure:  a. Compact bone: Outer layer. It is hard substance.  b. Cancellous (Spongy) bone: It lies within the compact bone. It is formed of network of delicate trabeculae with intervening spaces that contains red marrow.  - Each long bone is formed of two ends (epiphysis) and a shaft (diaphysis).  - The shafts of long bones have in addition, in the center, a space called the medullary cavity.  - Flat bones of skull are composed of an outer and an inner table of compact bone enclosing a layer of spongy bone called diploe.  C- Types of bones according to region:  1) Axial bones consist of:  a. Skull  b. Vertebral column.  c. Ribs.  d. Sternum  2) Appendicular bones consist of:  a. The bones of the upper limbs.  b. The bones of the lower limbs.