FHB 101 General Anatomy PDF

FHB 101 General Anatomy By PROf.DR. Nahed koura Dr. Waleed Ahmed Badaway Introduction Anatomy is the science dealing with the structure of the human body....

FHB 101 General Anatomy By PROf.DR. Nahed koura Dr. Waleed Ahmed Badaway Introduction Anatomy is the science dealing with the structure of the human body. It is a descriptive science and its language includes accurate anatomical terms many of which derived from Latin or Greek. Anatomical position: For descriptive purposes, the body is supposed to be in the erect posture, with the arms hanging by the sides and the palms of the hands directed forward and the feet pointing forwards. Anatomical planes: The various parts of the body are described in relation to certain imaginary planes as followed: 1- Sagittal plane: This is an imaginary vertical plane passing from top to bottom and from front to back, dividing the body into right and left parts. a. Median plane: is a Sagittal plane passing through the center of the body, dividing it into equal right and left halves. b. Parasagittal planes: they are Sagittal planes parallel to median plane divide the body into unequal right and left parts. 2- Coronal planes: These planes are imaginary vertical planes at right angles to the median plane. It divides the body or a structure into anterior and posterior parts. 3- Horizontal, or transverse, planes: These planes are imaginary planes that are at right angles to both the median and the coronal planes. They divide the body or the part into upper and lower parts. Fig.1: The anatomical position Median plane Coronal plane Horizontal plane Fig.2: The anatomical planes The description of the position of the body parts relative to each other is practised by using specific anatomical terms as followed: *The anatomical terms: 1- Medial: means that the structure is situated nearer to the median plane. 2- Lateral: means that the structure lies farther away from the median plane. 3- Anterior or ventral: denoting the front of the body also anterior structure is that one placed nearer to the front of the body than another one. 4- Posterior or dorsal: denoting the back of the body also posterior structure is that one placed nearer to the back of the body than another one. NB: In the hand the terms palmar and dorsal surfaces are used in place of anterior and posterior. 5- The term proximal means nearer to the point of attachment of a limb to the trunk.  6- The term distal means far away from the point of attachment of a limb to the trunk; for example, the arm is proximal to the forearm. 7- Superficial: means present nearer to the surface of the body. The opposite term is Deep ( away from the surface). 8- The terms superior means situated above, or higher. 9- The terms inferior means situated below, or lower NB: -Sometimes cranial is used if the structure is closer to the head while the other structure should be caudal -The terms dorsal and planter surfaces of the foot are used instead of superior and inferior surfaces. 10- Internal (inside) means that the structure is nearer to the center or a cavity of an organ. 11- External (outside) means that the structure is away from the center of an organ or cavity. THE SKIN It is divided into two layers, the superficial is the epidermis and the deep is the dermis. The epidermis is stratified epithelium while the dermis is formed of connective tissue. Collagen fibers in dermis are arranged in rows termed lines of cleavage (Langers’s lines). The surgical incisions should be done along or between these rows.  The FASCIA It lies deep to the skin. The fascia is divided into superficial and deep layers. The superficial fascia or subcutaneous tissue is a mixture of loose and adipose tissue uniting the dermis of the skin with the deep fascia. The deep fascia is a membranous layer of connective tissue that invests the muscles and deep structures. It sends fibrous septa between the groups of muscles forming separate compartments or making fascial spaces as in the neck. This plays an important role in surgery. In these spaces blood or pus may collect and need to be drained surgically. Connective tissue helps in the repair of wounds. The deep fascia may be thickened to form bands called retinacula.  The Musculoskeletal System BONES, JOINTS AND MUSCLES: They form a triad of the musculoskeletal system. BONES JOINTS MUSCLES The Skeleton The skeleton consists of bones and cartilages. Bones provide a framework of levers, they protect organs such as the brain and heart, their marrow forms certain blood cells, and they store and exchange calcium and phosphate ions. The skeletal system is divided into two main parts axial skeleton and appendicular skeleton. 1-Axial skeleton: It consists of the bones of the skull, vertebral column, hyoid bone, ribs and sternum. a- The skull: It is the skeleton of the head; it is divided into two parts, the cranium and the mandible. b- The vertebral column: It is a curved and flexible column, formed of a series of bones called vertebræ. The vertebræ are thirty-three in number, and according to the regions they occupy; there are 7 in the cervical region, 12 in the thoracic, 5 in the lumbar, 5 in the sacral, and 4 in the coccygeal. In the sacral region, the 5 sacral vertebrae united together to form the sacrum.  7 cervical 5 Regions 12 thoracic 5 lumbar 33 5 Sacral 4 Coccygeal vertebrae c- Hyoid bone: It lies in the upper most part of the neck below the mandible and above the larynx. It has a body, two greater horns and two lesser horns d- The ribs and sternum:  The sternum is a flattened bone in the midline in front of the thoracic cage. It consists of manubrium (its upper part), the body (its middle part) and the xiphoid process (its small lower part).  The ribs are 12 ribs on either side of the thorax. They are obliquely placed bony arches. Each rib has a head, neck and shaft. Each rib articulates posteriorly by its head with the body of thoracic vertebrae. Each rib articulates anteriorly by its costal cartilage with the sternum till the 7 th rib while the costal cartilages of the 8th, 9th, and 10th ribs articulate with each other. The last two ribs have a free anterior end and called floating ribs.  Fig.9a: hyoid bone Thoracic inlet Ribs Costal cartilages Sternum Thoracic outlet The thoracic cage 2-Appendicular (peripheral) skeleton: It consists of bones of the limbs. The bones of each limb are divided into proximal, intermediate and distal segments. The bones forming the segments of the limbs are presented in the following table:  Segment Upper limb Lower limb Proximal Humerus Femur Intermediate Radius and ulna Tibia and fibula Tarsal bones(7) Carpal bones(8) Metatarsals(5) Metacarpals(5) Phalanges, three Distal segment Phalanges, three in each in each toe finger but two only in but two only in the thumb. the big toe. Clavicle Sacrum Scapula Hip Humerus Proximal Femur Tibia ulna Intermediate Fibula radius 8 carpals 7 tarsals 5 metacarpals Distal 5 metatarsals phalanges Phalanges The upper limb The lower limb  Bones Bone is essentially a highly vascular mineralized connective tissue that consists of cells and an intercellular matrix. The bone matrix is composed mainly of collagen fibres and inorganic salts rich in calcium and phosphate giving the bone its remarkable hardness. N.B: The term osteology, meaning the study of bones, is derived from the Greek word osteon, meaning "bone."  Types of bones: Bones may be classified according to shape into: 1- Long bones are those in which the length exceeds the breadth and thickness. They include the clavicle, humerus, radius, ulna, femur, tibia, and fibula, and also the metacarpals, metatarsals, and phalanges. Each long bone has a shaft and two ends. 2- Short bones are cuboidal in shape and they are found in tarsus of the foot and carpus of the hand. 3- Sesamoid bones are another type of short bones that developed in tendon of certain muscles as the patella of the knee. 4- Flat bones are broader than their thickness as the bones of the skull cap. 5- Irregular bones have various shapes as the vertebrae and bones of the face. 6- Pneumatic bones contain air-filled spaces as the bone around the nasal cavity in the skull. Flat bones Irregular bones Long bones Pneumatic Short bones bones Types of bones  Structure of bone: According to structure there are two types of bones: 1-Compact bone: this type forms the hard outer layer of bones 2- Spongy or Cancellous bone: this type forms the interior filling which is composed of a network of rod- and plate-like elements that make the overall organ lighter and allow rooms for blood vessels and bone marrow. Compact bone Spongy bone The Structure of bone  Bone development: All bones begin as mesenchymal proliferations that appear early in the embryonic period and takes one of two forms: 1- Membrane bones: where the membrane of mesenchyme directly ossify into bone. 2- Cartilage bones: The mesenchymal proliferations become chondrified as the cells lay down cartilage matrix and form hyaline cartilages that have the shapes of the future bones. These cartilages are then replaced by bone.  Development of cartilaginous bone  Development and growth of long bone:  Long bone developed as cartilage bone which is formed by ossification of preformed cartilaginous model that gradually ossified into bone.  This process starts by the appearance of osteoblasts (the bone forming cells) in the shaft of the cartilaginous model forming the primary ossific center. The process of ossification spreads from the center along the shaft. Later on another centers of ossification started to appear in both ends of the bone. N.B: Osteoclast is responsible for bone resorption thus they break down bone.  Parts of a growing long bone:  Diaphysis: referred to the shaft of long bone and it is formed of a cylinder of compact bone.  Epiphysis: referred to the end of long bone and it is formed of spongy bone  Articular cartilage: it is thin layer of hyaline cartilage that remains unossified and covers the epiphysis.  Epiphyseal plate: a plate of cartilage lying between epiphysis and diaphysis where increase in length of the bone takes place.  Metaphysis: it is the part of the shaft close to epiphyseal plate.  Periosteum: is a thick layer of fibrous tissue that covers all bone surfaces except the articulating surface.  Medullary cavity: it is a cavity in the shaft containing bone marrow.  Articular cartilage Epiphysis Epiphysial plate Metaphysis Diaphysis Medullary cavity Periosteum Parts of a growing long bone Cartilages During early fetal life the human skeleton is mostly cartilaginous, but is subsequently largely replaced by bone. In adults cartilage persists at the surfaces of synovial joints, in the walls of the larynx, trachea, bronchi, nose and external ears, in the epiglottis and as isolated small masses in the cranial base.  Developmental replacement by bone is a complex process, and cartilaginous growth plates between ossifying epiphyses and diaphyses of long bones and elsewhere continue to proliferate, increasing the length of the bones concerned until they eventually ossify, when growth ceases.  Cartilage types: Cartilage is categorized into three types which include: 1. Hyaline cartilage :  It is a low friction, wear-resistant tissue presents within joints that is designed to bear and distribute weight.  It is a strong, rubbery, flexible tissue but has a poor regenerative capacity. 2. Elastic cartilage:  Elastic cartilage is more flexible that hyaline cartilage and is present in the ear, larynx and epiglottis. 3. Fibrocartilage:  The Muscles The muscles are formed of specialized cells that have the ability to change their shape in a process called muscle contraction. This contraction will move limbs, inflate the lungs, pump blood, close and open tubes and so on. There are three distinct types of muscles: skeletal muscles, cardiac or heart muscles, and smooth (non-striated) muscles. The skeletal muscles:  Skeletal muscles imply their name because they are attached to the skeleton and produce its movements.  The majority of these movements are initiated under conscious control therefore, they are called voluntary muscles.  They are consisted of striated, multinucleated fibers.  A skeletal muscle has belly and two ends represent its attachments to the skeleton.  The belly is the fleshy part of the muscle.  The muscles attachments may be: a. Directly through the muscular tissue itself. b. Through fibrous structures which may be : 1. Tendon: cord-like fibrous tissue. 2. Aponeurosis: flattened sheet-like fibrous tissue. 3. A raphe is an interdigitation of the tendinous end of fibers of flat muscles. c. Through a combination of both fleshy and fibrous structures.  Each muscle is attached at both of its end.  The relatively fixed attachment is called its origin while the relatively movable attachment is called its insertion.  Attachment Belly Attachment The attachments of the skeletal muscle Direct Tendon Aponeurosis Raphe Types of skeletal muscles attachments  Terms related to movements produced by muscles contraction: 1- Flexion is the approximation of two ventral surfaces or bending or the making of an angle, but it is occasionally dorsal, as in the case of the knee joint. 2- Extension means straightening it is the return from flexion and usually takes place in a posterior direction but in the knee extension is in an anterior direction. 3- Abduction is the movement away from the midline of the body. 4- Adduction is the opposite of abduction. It is a movement towards midline of the body. 5- Medial rotation is the rotation towards the median plane. 6- Lateral rotation is the rotation away from the median plane. N.B: In the forearm; -Pronation is the medial rotation of the forearm. -Supination is the lateral rotation of the forearm. While, in the foot; -Inversion is the medial rotation of the foot. -Eversion is the lateral rotation of the foot. 7- Circumduction is a circular movement, of a limb or of the eye, produced by the combination of the movements of flexion, extension, abduction, and adduction. 8- Protraction is to move forward while retraction is to move backward.(used to describe the forward and backward movement of the jaw or scapula). Flexion & extension Abduction & adduction  Nerve supply of skeletal muscle: The nerve trunk to muscle is a mixed nerve, motor and sensory, also contains some sympathetic autonomic fibers. N.B: paralysis (inability to move the muscle) of a muscle occur when its nerve supply is interrupted and the muscle become flaccid and will atrophy. Action of skeletal muscles: According to muscle action on a certain joint a muscle may be one of the following: 1- Prime mover is the chief muscle for particular movement. 2- Antagonist is a muscle opposes the action of the prime mover. 3- Fixator stabilizes the origin of the prime mover so that it can act efficiently. 4- Synergist muscle stabilizes the intermediate joints crossed by the prime mover before it reaches its target joint. Different forms of skeletal muscles according to arrangement of their fibers: 1- Pennate muscles show a central tendineous axis and short parallel muscle fibres are attached obliquely to it. It may take one of the following forms: a. Unipennate, b. Bipennate, c.Multipennate. 2- Parallel (strip) muscles, in which the muscle fibers are parallel from end to end. Some strip muscles have tendinous intersections as the rectus abdominis. 3- Triangular form where the muscle fibers are narrow at one and wide at the other end as adductor longus muscle of the thigh. 4- Spindle-shaped or fusiform like biceps 5- Circular: around openings like orbicularis oris Different forms of skeletal muscles  Joints A site where two or more bones come together is called a joint. Joints are classified into fibrous, cartilaginous, and synovial joints. A) Fibrous joints: The articulating surfaces of the bones are joined by fibrous tissue, and thus very little movement is possible. The articulating bones are separated by fibrous connective tissue. The fibrous joints include three types: 1. Suture is the type of fibrous joint that present between the bones of the skull cap. 2. Syndesmosis is a fibrous joint that is found between long bones of the body, such as the radius and ulna in forearm and the inferior tibio-fibular joint in leg. 3. Gomphosis is a type of fibrous joint that fixes the roots of the teeth in the alveolar sockets of jaws by the periodontal ligament. The sutures of the skull Syndesmosis B) Cartilaginous joints: Cartilaginous joints are connected entirely by cartilage either fibrocartilage or hyaline.Cartilaginous joints can be divided into two types: 1- A primary cartilaginous joint: in this type the bones are united by a plate of hyaline cartilage. This joint permits no movement and will ossify with age. For example the joint between the epiphysis and the diaphysis of growing bones. 2- A secondary cartilaginous joint in this type the bones are united by a plate of fibrocartilage and the articular surface of the bones are covered by a thin layer of hyaline cartilage. This type permits small amount of movement and doesn’t ossify with age. For example the midline joints as the intervertebral disc and the symphysis pubis. Primary cartilaginous Secondary cartilaginous C) Synovial joints: Synovial joint is the most common and most movable type of joint in the body i- The structure of synovial joints consists of: 1. The articular carliage: it is a thin layer of hyaline cartilage covers the articular surfaces of the bones. 2. The joint cavity: a cavity separates the articular surfaces and permits a great degree of movement. 3. The fibrous capsule: articulated bones are held together by a fibrous sheath outside the cavity. The fibrous capsule maybe thickened in certain parts forming the capsular ligaments. 4. The synovial membrane lines the inner surface of the capsule and covers the non articular parts of the bone inside the capsule. 5. The synovial fluid: a fluid produced by the synovial membrane filling the joint cavity and acts as lubricant. The structure of synovial joints ii- Synovial joints can be classified according to the arrangements of the articular surfaces and the types of movement that are possible into the following:  Plane joints:Examples: many inter-carpal and inter-tarsal joints.  Hinge joints:Examples: elbow and ankle joints.  Pivot joints: Examples: the atlanto-axial and superior radioulnar joints.  Condyloid joints:Examples: the metcarpophalangeal joints (knuckle joints).  Ellipsoid joints:Example: wrist joint also known as the radiocarpal joint.  Saddle joints: Example: the carpometacarpal joint of the thumb.  Ball and socket joints:Examples: the shoulder and hip joints.  The Cardiovascular System The cardiovascular system, composed of the heart and blood vessels, is responsible for circulating blood throughout the body to transport oxygen, nutrients, hormones and cellular waste products throughout the body A) The heart:  Position of the heart: The heart is a hollow muscular organ located in the thoracic cavity between the two pleura and lungs just behind and to the left of the body of the sternum. About one third of the heart lies to the right of middle line, while the other two third are to the left. Left Right lung lung Heart 1/3 2/3 Diaphragm : Position of the heart B) Blood vessels: The blood vessels are part of the circulatory system and function to transport blood throughout the body. There are three types: arteries, veins, and capillaries. 1- The arteries:  They transport the blood from the heart.  They carry oxygenated blood except the pulmonary artery which carries deoxygenated blood.  Their very small branches are called arterioles.  They do not have valves.  Their walls are thick as it contains a thick muscular layer.  Their walls contain an elastic layer so they don’t collapse when cut.  2- Veins:  They transport the blood toward the heart.  They carry deoxygenated blood except the pulmonary veins which carries oxygenated blood.  The very small veins are, called venules, unite to form veins.  They have valves to help drain blood against gravity.  Their walls are thin as it contains a thin muscular layer.  Their walls don’t contain an elastic layer so they collapse when cut. 3- Capillaries:  They are microscopic vessels in the form of a network.  They connect the arterioles to the venules.  The capillaries contain low blood pressure.  Their thin wall and pressure gradient enable exchange of nutrients, gases and waste product between the blood and tissue fluids. N.B: - In some areas of the body, principally the tips of the fingers and toes, direct connections occur between the arteries and veins without the intervention of capillaries. This is called an arteriovenous anastomosis. - Blood sinusoids resemble capillaries but they have an irregular cross diameter and are wider than capillaries. They are found in the bone marrow, spleen, liver and some endocrine glands. venules Valve in a Arterioles vein Capillaries  Lymphatic system The lymphatic system consists of the lymph nodes and lymphvessels as well as the spleen, and tonsils. The fluid that circulates inside lymph vessels is called lymph which is rich in lymphocytes that combat infection. Lymph starts formation in the intercellular tissue spaces and flows inside the lymph vessels which are interrupted at varioussites by lymph nodes. The thoracic duct is the largest and longest lymphatic vessel, and pours its content of lymph in the venous blood carried by large veins in the root of the neck. Lymph drains eventually into the venous blood. Lymph vessels are absent in the brain, spinal cord, cornea and cartilage.  Nervous system The nervous system is divided into central (CNS) and peripheralnervous (PNS) systems. The central nervous system consists of the brain and spinalcord. The peripheral nervous system consists of all the peripheral cranial and spinal nerves and the nervous ganglia which are either sensory dorsal root ganglia or autonomic ganglia of the autonomic nervous system. The autonomic ganglia are either sympathetic or parasympathetic. The nervous ganglia are collection of nerve cells outside the central nervous system.  The peripheral nerves are either cranial attached to the brain or spinal attached to the spinal cord. There are 12 pairs of cranialnerves attached to the brain, and 31 pairs of spinal nerves attached to the spinal cord. The spinal nerves are 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. The spinal nerves canmake plexuses. Each spinal nerve is attached to the spinal cord by two roots (anterior and posterior). The anterior (ventral) root is motor, while the posterior (dorsal) root is sensory. The two roots join each other in the intervertebral foramen to form the trunk of the spinal nerve which is thus mixed motor and sensory. The trunk of each spinal nerve is short and divides into anterior and posterior primary rami, just after leaving the intervertebralforamen. Thus the trunk of the spinal nerve The posterior or dorsal root of a spinal nerve carries a dorsal or sensory ganglion, while the anterior or ventral root carriespreganglionic autonomic fibers. Referred pain means a pain felt in a part of the body other thanits actual source. It means pain arising in viscera which are supplied by autonomic nerves, but is felt in the body wall which asimilar sensory supply (referred to it). Pain from the heart cannot be felt in the heart itself, but is felt in the anterior chest wall (pectoral region), and may radiate to the left arm.