Introduction to Human Skeletal System


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Introduction to Human Skeletal System

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  • Skeleton includes bones and cartilages.It forms the main supporting framework
  • hape and supportMuscular attachment Act as leversProtection of organsErythropoiesisStorage of minerals
  • Introduction to Human Skeletal System

    1. 1. For the students of Gulf Medical University, Ajman, DMD Dr. Seyed Morteza Mahmoudi, MBBS Gulf Medical University, Ajman
    2. 2.  At the end of the session students should be able to:  1) Name the parts of human skeleton  2) Identify and explain the purpose of some bones in the human skeleton  3) List the bones forming every part  4) Classify bones according to origin, shape and structure
    3. 3.  Skeleton is a system made up of bones and cartilages and supported and supplemented by ligaments, tendons and muscles.  It serves as a scaffold which supports organs, anchors muscles, and protects organs.
    4. 4. What are Bones (Oss)? What are their functions?
    5. 5.  Bone is a specialized connective tissue, consisting of cells, fibers and extracellular matrix. It’s a hard clacific, with adynamic structure.  Functions:  Mechanical     Protection Movement Structure Sound transduction  Synthetic,  Hematopoiesis  Metabolic  Mineral storage  Acid base balance  Endocrine function
    6. 6.  8 cranial  14 facial  6 ear bones  Hyoid bone  26 vertebrae (7 cervical, 12 thorax, 5 lumbar, the sacrum which is five fused vertebrae, and the coccyx which is four fused vertebrae)  24 ribs plus the sternum  The shoulder girdle (2 clavicles and 2 scapulae)  The pelvic girdle (2 fused bones)  30 bones in our arms and legs (a total of 120);  Total No. 206
    7. 7. How do we classify bones?
    8. 8. Contents Classification of bones Shape Development Region Structure
    9. 9. Shape Long bones Short bones Flat bones Irregular bones Pneumatic bones Sesamoid bones Accessory bones
    10. 10.  Long bones:  Shaft with two ends  Develop by intracartilagenous ossification  Three centers of ossification  Central medullary cavity  Nutrient foramina  E.g. humerus, ulna, femur etc.  Short long bones:  Shaft with one end  Have two centers of ossification  E.g. metacarpal and metatarsal bones  Modified long bones:  No medullary cavity  E.g. clavicle
    11. 11.  Have no shaft or ends  Shape is cuboid, trapizoid or cuniform.  Carpal and tarsl bones
    12. 12.  Skull  Ribs  Sternum  Scapula
    13. 13.  Bone that contain air-filled spaces
    14. 14.  Bony nodules embedded in tendons/ joints  No periosteum and ossify after birth  E.g. Patella, pisiform
    15. 15. Contents Classification of bones Shape Development Region Structure
    16. 16. Development Crtilaginous bones Membraneous bones Membrano-cartilaginous bones
    17. 17.  All bones: mesodermal origin.  Process of bone formation: ossification Endochondral Formed in a hyaline cartilage model. Results in the formation of the long bones, Intramembraneous Bone laid dawn directly in fibrous mesenchymal connective tissue. Results in the formation of the cranial bones and the clavicles.
    18. 18. Osteoblasts Osteocytes Osteoclasts
    19. 19.  Cartilaginous bones: ossify over a cartilagenous tissue: bones of limbs, vertebral column  Membraneous bones: ossify over mesenchymal tissue: vault, facial bones  Membrano-cartilaginous bones: partly from cartilage and partly from mesenchymal ossification: clavicle, mandible
    20. 20. Contents Classification of bones Shape Development Region Structure
    21. 21. Region Axial Skeleton Appendicular Skeleton
    22. 22. Contents Classification of bones Shape Development Region Structure
    23. 23. Structure Macroscopic Microscopic • Compact: dense, cortex of long bones • Cancellous: meshwork of trabeculae • Lamellar : mature human bones • Fibrous: young fetal bones
    24. 24. Diaphysis Epiphysis Epiphyseal growth plate Metaphysis
    25. 25. Periosteum Endosteum Bone marrow (yellow/red) Hyaline cartilage
    26. 26.  Diaphysis: shaft of a long bone which ossifies from primary      center Epiphysis: ends and tips of bone which ossify from secondary centre Pressure epiphysis: articular and takes part in transmission of weight. Eg. Head of femur, lower end of radius Traction epiphysis: non articular- provides attachment of one or more tendons which exert a traction on epiphysis. These ossify later than the pressure epiphysis. Atavistic epiphysis: independent bone- which in man is fused to another bone- coracoid process of scapula Aberrant epiphysis: not always present- head of the 1st metacarpal and base of the other metacarpals
    27. 27.  Epiphyseal plate of cartilage: separates epiphysis from metaphysis. Proliferation of cells lengthwise growth of a long bone in cartilage-  Metaphysis: ends of diaphysis merging into the epiphysis. Zone of active growth. Richly supplied by blood vessels. Common site for osteomyelitis because of entrapment of bacteria and emboli in the bend of the blood vessels
    28. 28.  Covering the long bone in all area, except the articular surfaces is periosteum.  Deep to the periosteum is a layer of compact bone This layer is thicker in the diaphysis than the epiphysis  Covering the articular surfaces is articular cartilage, or hyaline cartilage.
    29. 29.  In the diaphysis of the long bone deep to the compact bone is the medullary cavity.  In the adult it is full of yellow bone marrow.  The medullary cavity is lined with endosteom.  In the epyphysis deep to the layer of compact bone is spongy bone.  Between the trabacula of the spongy bone is red bone marrow.
    30. 30.  Nutrient artery  Periosteal artery  Epiphyseal artery  Metaphyseal artery