Skeletal system


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Skeletal system

  1. 1. Skeletal system 206 bones (in adults) Cartilages Joints with ligaments and tendons
  2. 2. Divisions of the skeleton <ul><li>Axial - </li></ul><ul><ul><li>Ribs, sternum, vertebrae, skull </li></ul></ul><ul><li>Appendicular – </li></ul><ul><ul><li>Arm and leg bones, clavicle, scapula, hip bones </li></ul></ul>
  3. 3. Functions <ul><li>1.    Supports body as a whole, supports individual organs and organ systems. </li></ul><ul><li>2.    Directs the forces of skeletal muscle contraction, producing movement. </li></ul><ul><li>3.    Individual bones store minerals. </li></ul><ul><li>4.    Protect delicate tissues and organs by storing them within bones or surrounding them with a bony shield. Ex: brain. </li></ul><ul><li>5.    Blood cell formation in bone marrow of flat bones. </li></ul>
  4. 4. Parts of a Long Bone <ul><li>Periosteum </li></ul><ul><li>Epiphysis </li></ul><ul><ul><li>Articular cartilage </li></ul></ul><ul><li>Diaphysis </li></ul><ul><ul><li>Medullary cavity - endosteum </li></ul></ul><ul><ul><ul><li>Bone marrow </li></ul></ul></ul><ul><ul><ul><ul><li>Yellow </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Red - hematopoiesis </li></ul></ul></ul></ul><ul><li>Processes , grooves, openings, depressions etc. </li></ul>
  5. 5. Bone Development and Growth <ul><li>Intramembranous bones </li></ul><ul><li>Endochondral bones </li></ul><ul><li>Osteoblast – bone forming cell </li></ul><ul><li>Osteoclast – bone eroding cell </li></ul>
  6. 6. Development of Endochondral Bones <ul><li>1. Develop from masses of hyaline cartilage. </li></ul><ul><li>2. Primary ossification center forms in center of bone. Cartilage begins to break down. Periosteum forms Blood vessels and osteoblasts invade disintegrating cartilage, spongy bone is formed in its place. </li></ul><ul><li>3. Compact bone forms around p.o.c. Ends of bones are still cartilage and continue to grow </li></ul>
  7. 7. <ul><li>4. Secondary ossification centers appear in each epiphysis, spongy bone forms in all directions from them </li></ul><ul><li>5. Epiphyseal disk is a band of cartilage that remains between p.o.c. and s.o.c. This still grows to increase bone length </li></ul><ul><li>6. Epiphyseal disk becomes ossified, bone can not get any longer. </li></ul><ul><li>* Bone is continually broken down and reformed throughout life. </li></ul>
  8. 8. Repair of Bone Fracture <ul><li>Fracture – break in bone – both blood vessels within bone and Periosteum are ruptured. Periosteum probably torn. </li></ul><ul><li>Hematoma – blood escaping from broken blood vessels forms a clot. </li></ul><ul><li>Cartilaginous callus – fibrocartilage that fills gap between the ends of the broken bone. </li></ul><ul><li>Bony callus – cartilaginous callus is broken down, area is invaded by blood vessels and osteoblasts. More bone is produced than necessary. Over time, osteoclasts remove excess and shape it. </li></ul>
  9. 9. Types of breaks <ul><li>Simple fracture – just the bone and Periosteum break. </li></ul><ul><li>Compound fracture – ends of broken bone protrude through the skin. Much more dangerous; susceptible to infection. </li></ul><ul><li>Hairline – bone breaks but does not separate. </li></ul><ul><li>Transverse – straight across the bone </li></ul>
  10. 10. <ul><li>Spiral – diagonally across the bone, usually from a twisting pressure. </li></ul><ul><li>Greenstick – bone splinters – usually happens in younger more supple bone. Looks like a fresh branch broken off a tree. </li></ul><ul><li>Colles – Processes of bones in the wrist break off. </li></ul><ul><li>Potts – Processes of bones in the ankle break off. </li></ul>
  11. 11. <ul><li>Compression – Usually in vertebrae, from a hard fall on the rear end or the head. </li></ul><ul><li>Epiphyseal plate – a break that occurs in the cartilage band of a growing bone. May stunt growth as epiphyseal plate ossifies during healing. Bone will stop growing at that end. </li></ul>
  12. 12. Joints – functional junctions between bones – articulations <ul><li>1.    Immovable joints – synarthroses </li></ul><ul><li>Bones are fastened tightly together by a thin layer of fibrous connective tissue. Occur between bones that come in close contact with one another. </li></ul><ul><li>Ex: sutures between flat bones of the cranium. </li></ul>
  13. 13. 2.    Slightly movable joints – amphiarthroses <ul><li>Bones are connected by fibrocartilage or ligaments. </li></ul><ul><li>Ex: Vertebrae, sacroiliac joints (in pelvis); each joint only moves a little. The combination of many gives us motion in many directions. </li></ul>
  14. 14. 3.    Freely movable joints – diarthroses/synovial joints <ul><li>surrounded by a capsule of synovial fluid inside a membrane. Lubricates articular cartilage of joint. Bursae – fluid filled sacs inside the joint that act as ball bearings and aid in movement of tendons that pass over bony parts or over other tendons. </li></ul>
  15. 15. Types of freely movable joints <ul><li>Ball and Socket </li></ul><ul><ul><li>Ball shaped head fits into cup shaped socket. Widest range of motion of any joint. Movement in all planes and rotation </li></ul></ul><ul><ul><li>Ex: hips and shoulders </li></ul></ul><ul><li>Condyloid </li></ul><ul><ul><li>Oval shaped condyle of one bone fits into an elliptical cavity of another bone. Movement in different planes but no rotation. </li></ul></ul><ul><ul><li>Ex. Joints between metacarpals and phalanges </li></ul></ul>
  16. 16. <ul><li>Gliding </li></ul><ul><ul><li>Articulating surfaces nearly flat or slightly curved. Sliding and twisting motion. </li></ul></ul><ul><ul><li>Ex: carpals, tarsals </li></ul></ul><ul><li>Hinge </li></ul><ul><ul><li>Convex surface of one bone fits into concave of another. Movement in one plane only. </li></ul></ul><ul><ul><li>Ex: Knee and elbow, phalanges </li></ul></ul>
  17. 17. <ul><li>Pivot </li></ul><ul><ul><li>Cylindrical surface of one bone rotates within a ring formed of bone and fibrous tissue. Movement is rotation about a central axis. </li></ul></ul><ul><ul><li>Ex: joint between proximal ends of radius and ulna, top 2 vertebrae of spine (atlas and axis.) </li></ul></ul><ul><li>Saddle </li></ul><ul><ul><li>Articulating surfaces have both concave and convex regions. Surface of one bone fits the complementary surfaces of the other. Movement in all planes but no rotation. </li></ul></ul><ul><ul><li>Ex: carpal and metacarpal of thumb (only place) </li></ul></ul>
  18. 18. Movements of Joints <ul><li>Flexion – bending in toward the body or forward. </li></ul><ul><ul><li>Ex: make a fist </li></ul></ul><ul><li>Extension – straighten or bend away from the body. </li></ul><ul><ul><li>Ex: kick a ball, extension of knee </li></ul></ul><ul><li>Hyperextension – bend past straight </li></ul><ul><ul><li>Ex: bend head back </li></ul></ul>
  19. 19. <ul><li>Adduction – move medially </li></ul><ul><ul><li>Ex: legs together at attention </li></ul></ul><ul><li>Abduction – move laterally </li></ul><ul><ul><li>Ex: legs apart at ease </li></ul></ul><ul><li>Elevation – raise up </li></ul><ul><ul><li>Ex: shrug shoulders up </li></ul></ul><ul><li>Depression – lower </li></ul><ul><ul><li>Ex : open mouth (depress jaw) </li></ul></ul>
  20. 20. <ul><li>Rotation – pivot on an axis </li></ul><ul><ul><li>Ex: shake head no </li></ul></ul><ul><li>Circumduction – move in circles </li></ul><ul><ul><li>Ex: giant arm circles </li></ul></ul><ul><li>Protraction – move anteriorly </li></ul><ul><ul><li>Ex: grasp upper lip in teeth </li></ul></ul><ul><li>Retraction – move posteriorly </li></ul><ul><ul><li>Ex: grasp lower lip in teeth </li></ul></ul>
  21. 21. <ul><li>Supination – rotate hand palm up </li></ul><ul><li>Pronation – rotate hand palm down </li></ul><ul><li>Plantar flexion – point toes down </li></ul><ul><li>Dorsiflexion – point toes up </li></ul><ul><li>Inversion – turn sole of foot medially </li></ul><ul><li>Eversion – turn sole of foot laterally </li></ul>