Lecture Outline: A First Look at Anatomy PDF

•Dr.Ali albassam MBBS .MSc .PhD rd •3 Lecture Outline: A First Look at Anatomy Dr.ali albassam MBBS .MSc .PHD 3rd Lecture Outline: A First Look at Anatomy 2 Basic Structures Objectives of the lecture • - Introduction to the bones • - Types of joints 3 Bone is a living tissue capable of chang...

•Dr.Ali albassam MBBS .MSc .PhD rd •3 Lecture Outline: A First Look at Anatomy Dr.ali albassam MBBS .MSc .PHD 3rd Lecture Outline: A First Look at Anatomy 2 Basic Structures Objectives of the lecture • - Introduction to the bones • - Types of joints 3 Bone is a living tissue capable of changing its structure as the result of stresses to which it is subjected. Like other tissue bone consists of cells, fibers & intercellular matrix. It is hard because of the calcification of its extracellular matrix& possesses a degree of elasticity because of the presence of organic fibers 4 Function of Bones • Support – provides hard framework • Protection of underlying organs • Movement • Mineral storage • Blood-cell formation – bone contains red marrow Classification of Bones • Long bones – humerus & femur • Short bones – carpal bones • Flat bones – sternum & scapula • Irregular bones – vertebrae • Sesamoid bones – patella Classification of The bone exists in two forms: a compact & cancellous. The compact bone appears as a solid mass. The cancellous bone consists of a branching network of trabeculae.The trabeculae are arranged in such a manner as to resists the stress & strains to which the bone is exposed. The bones can be classified as follows based on their general shape: Long bones,short bones,Flat bones,irregular bones & sesamoid bones 7 Classification of Bones  Long bones  Typically longer than wide  Have a shaft with heads at both ends  Contain mostly compact bone • Examples: Femur, humerus Classification of Bones  Short bones  Generally cube-shape  Contain mostly spongy bone  Examples: Carpals, tarsals Classification of Bones on the Basis of Shape Classification of Bones  Flat bones  Thin and flattened  Usually curved  Thin layers of compact bone around a layer of spongy bone  Examples: Skull, ribs, sternum Classification of Bones  Irregular bones  Irregular shape  Do not fit into other bone classification categories  Example: Vertebrae and hip Structure of a Typical Long Bone • Diaphysis – “shaft or body ” of the bone • Epiphysis – ends of the bone • Blood vessels – well vascularized • Medullary or bone marorw cavity – hollow cavity – filled with marrow • Membranes – periosteum, Sharpey’s fibers, and endosteum Structure of Short, Irregular, Flat and Sesamoid Bones The Skeleton • Consists of bones, joints, cartilage, and ligaments • Composed of 207 named bones grouped into two divisions • Axial skeleton (81 bones) • Appendicular skeleton (126 bones) Bony Markings • Projections{ ‫زوائد‬.‫} بروز‬that provide attachment for muscles and ligaments (tubercle{‫}حدبة‬, spine, process, line, ridge…..) • Projections that help form joints (condyle) • Depressions (fossa, grove) and openings (foramen) for passage of nerves and blood vessels Anatomical Terms Used to Describe Bone Features • Terms • Body: main part • Head: enlarged end • Neck: constriction between head and body • Margin or border: edge • Angle: bend • Ramus: branch off body • Condyle: smooth rounded articular surface • Facet: small flattened articular surface • Projections • Process: prominent projection • Tubercle: small rounded bump • Tuberosity: knob • Trochanter: tuberosities on proximal femur • Epicondyle: near or above condyle 7-18 Anatomical Terms Used to Describe Bone Features • Ridges • Line or linea: low ridge • Crest or crista: prominent ridge • Spine: very high ridge • Openings • • • • Foramen: hole Canal or meatus: tunnel Fissure: cleft Sinus or labyrinth: cavity • Depressions • Fossa: general term for a depression • Notch: depression in bone margin • Fovea: little pit • Groove or sulcus: deeper, narrow depression 7-19 20 7-21 The Skeleton Axial skeleton Appendicular Skull Hyoid Girdles Shoulder Vertebrae Sternum Clavicle Ribs Scapula Limbs Pelvic Two hip bones Upper Lower Arm humerus Thigh femur Forearm radius & ulna patella Hand carpus metacarpus phalanges Leg tibia & fibula Foot tarsus, metatarsus phalanges Joints • Functional junctions between bones • Classified according to the type of tissue that binds the bones together. • Joints (articulations) are unions or junctions between two or more bones or rigid parts of the skeleton. Joints exhibit a variety of forms and functions. Some joints have no movement, such as the epiphysial plates between the epiphysis and diaphysis of a growing long bone; others allow only slight movement, such as teeth within their sockets; and some are freely movable, such as the glenohumeral (shoulder) joint. 23 Fibrous Joints • Tightly joined by a layer of fibrous connective tissue. • Little or no movement occurs • Examples: • Suture between a pair of flat bones of the skull • Distal ends of tibia and fibula 24 The articulating bones of fibrous joints are united by fibrous tissue. The amount of movement occurring at a fibrous joint depends in most cases on the length of the fibers uniting the articulating bones. The sutures of the cranium are examples of fibrous joints . These bones are held close together, either interlocking along a wavy line or overlapping. A syndesmosis type of fibrous joint unites the bones with a sheet of fibrous tissue, either a ligament or a fibrous membrane. Consequently, this type of joint is partially movable. The interosseous membrane in the forearm is a sheet of fibrous tissue that joins the radius and ulna in a syndesmosis. A dento-alveolar syndesmosis (gomphosis or socket) is a fibrous joint in which a peg-like process fits into a socket, forming an articulation between the root of the tooth and the alveolar process of the jaw. Mobility of this joint (a loose tooth) indicates a pathological state affecting the supporting tissues of the tooth. 25 26 Cartilaginous Joints • A layer of cartilage joins bones • Allow limited movement. • Examples: • Intervertebral disks, composed of fibrocartilage separate the vertebrae of the vertebral column • 1st rib and sternum • Symphysis pubis 27 The articulating structures of cartilaginous joints are united by hyaline cartilage or fibrocartilage. In primary cartilaginous joints, or synchondroses, the bones are united by hyaline cartilage, which permits slight bending during early life. Primary cartilaginous joints are usually temporary unions, such as those present during the development of a long bone ,where the bony epiphysis and the shaft are joined by an epiphysial plate. Primary cartilaginous joints permit growth in the length of a bone. When full growth is achieved, the epiphysial plate converts to bone and the epiphyses fuse with the diaphysis. Secondary cartilaginous joints, or symphyses, are strong, slightly movable joints united by fibrocartilage. The fibrocartilaginous intervertebral discs between the vertebrae consist of binding connective tissue that joins the vertebrae together. Cumulatively, these joints provide strength and shock absorption as well as considerable flexibility to the vertebral column (spine). 28 29 30 Synovial Joints • Most joints with in the skeletal system • Bones covered with hyaline cartilage and held together by a fibrous joint capsule. 31 The articulating bones of synovial joints are united by a joint (articular) capsule (composed of an outer fibrous layer lined by a serous synovial membrane) spanning and enclosing a joint or articular cavity. The joint cavity of a synovial joint, like the knee, is a potential space that contains a small amount of lubricating synovial fluid, secreted by the synovial membrane. Inside the capsule, articular cartilage covers the articulating surfaces of the bones; all other internal surfaces are covered by synovial membrane. 32 33 Synovial Joints • Joint capsule consists of an outer layer of ligaments and an inner lining of synovial membrane. • Synovial membrane secretes synovial fluid which lubricates joint 34 Bursae • Located between the skin and underlying bony prominences. • Aid movement of tendons that pass over these bony parts or over tendons • Found in the elbow and knee 35 36 Types of Synovial Joints • Classified by: • Shapes of their parts • Movements they permit. 37 Ball-and-Socket joint • Ball-shaped head articulates with cup shaped cavity • Allows wider range of motion than any other kind • Movements in all planes as well as rotational movement around central axis • Examples: shoulder, hip 38 39 40 41 Condyloid joint • Oval-shaped bone fits into elliptical cavity • Variety of movements in different planes, but not rotational movement • Examples: metacarpals and phalanges 42 43 44 Hinge joint • Convex surface fits into concave surface • Permits movement in only one plane like a door hinge. Flexion and extension • Examples: elbows, and phalanges 45 46 47 Pivot joint • Cylindrical surface rotates with in ring of another bone and fibrous tissue • Rotation around a central axis • Examples: joint between proximal ends of radius and ulna 48 49 50 Saddle joint • Bones whose articulating surfaces have both concave and convex regions. Complementary surfaces fit together. • Permits a variety of movements • Examples: carpal and metacarpal of the thumb 51 Plane joints permit gliding or sliding movements in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement limited by their tight joint capsules. Plane joints are numerous and are nearly always small. An example is the acromioclavicular joint between the acromion of the scapula and the clavicle. 52 53 54 Types of Synovial Joints Based on Shape Figure 5.29a–c Slide 55 Types of Synovial Joints Based on Shape Figure 5.29d–f Slide 56 57 Synovial joints Axial Uniaxial Plane Biaxial Pivot Multiaxial Condyloid Hinge Ball & socket Metacarpophalangeal Radioulnar Acromioclavicular joint Shoulder Saddle Elbow Sterncostal Elipsoid Wrist 58 59 Joint Movements • Muscles fastened on either side of a joint produce movement of synovial joints. 60 Joint Movements • When the muscle contracts, its fibers pull its movable end (insertion) toward its fixed end (origin) and movement occurs at the joint. 61 62 63 Types of Joint Movements • Rotation: Moving a part around an axis (twisting the head from side to side) • Circumduction: Moving a part so that its end follows a circular path (moving a finger in a circular motion without moving the hand) 64 Types of Joint Movements • Pronation: Turning the hand so that the palm is downward or turning the foot so that the medial margin is lowered. • Supination: Turning the hand so that the palm is upward or turning the foot so that the medial margin is raised. 65 66 Types of Joint Movements • Eversion: Turning the foot so that the sole is outward • Inversion: Turning the foot so that the sole is inward 67 Types of Joint Movements • Retraction: Moving a part backward (pulling the chin backward) • Protraction: Moving a part forward (thrusting the chin forward) 68 Types of Joint Movements • Elevation: Raising a part (shrugging the shoulders) • Depression: Lowering a part (drooping the shoulders) 69 JOINT VASCULATURE AND INNERVATION Joints receive blood from articular arteries that arise from the vessels around the joint. The arteries often anastomose (communicate) to form networks (periarticular arterial anastomoses) to ensure a blood supply to and across the joint in the various positions assumed by the joint. 70 Joints have a rich nerve supply provided by articular nerves with sensory nerve endings in the joint capsule. However, most articular nerves are branches of nerves that supply the muscles that cross and therefore move the joint. The Hilton law states that the nerves supplying a joint also supply the muscles moving the joint and the skin covering their distal attachments. Articular nerves transmit sensory impulses from the joint that contribute to the sense of proprioception, which provides an awareness of movement and position of the parts of the body. The synovial membrane is relatively insensitive. Pain fibers are numerous in the fibrous layer of the joint capsule and the accessory ligaments, causing considerable pain when the joint is injured. The sensory nerve endings respond to the twisting and stretching that occurs during sports activities. 71 Arthritis • Disease that causes inflamed, swollen and painful joints • More than 100 different types affect 50 million people in the United States 72 73 THE END 74