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male child with open fracture of right humerus and a closed broken right…

- - - - no blood vessels or nerves
        
        mostly water
        
        highly resilient
        
        made up of chondrocytes
        
        wrapped in perichondrium
        
        chondrocytes
        
        encased in lacunae within ECM
        
        perichondrium
        
        girdle-like membrane around cartilage
        
        resists outward expansion of cartilage
        
        contains blood vessels that nourish cartilage
      - 3 main types of cartilage
        
        hyaline:
        
        flexible, resilient support
        
        most common cartilage in body
        
        mostly tough collagen fibers
        
        structures made of hyaline cartilage:
        joint cartilage, costal cartilage, upper respiratory cartilage &nasal cartilage
        
        fibrocartilage:
        
        tensile strength allows compression shock to be aborbed.
        
        contains thick collagen fibers
        
        structures make of fribrocartilage:
        intervertebral discs & knee menisci
        
        elastic:
        
        similar properties to hyaline except elastic fibers make up majority rather than collagen fibers.
        
        allows for structure to maintain shape while allowing great flexibility
        
        structures made of elastic cartilage:
        external ear & epiglottis
      - cartilage growth
        (2 ways)
        
        appositional growth:
        
        chondroblasts in perichondrium secrete matrix on external surface of cartilage, adding new cartilage on top.
        
        interstitial growth:
        
        chondrocytes in lacunae divide and secrete new matrix from within. Causing expansion from within
  - - - hematopoiesis:
        RBC are produced in red bone marrow cavities
      - storage:
        
        calcium
        
        phosphorus
        
        growth factors
        
        triglycerides
      - movement:
        act as levers for muscles to move on
      - support:
        supports body shape/posture as well as supporting soft organs
      - protection:
        protects brain, spinal cord and other vital organs
      - hormone production:
        a hormone called osteocalcin is secreted by bones to regulate insulin secretion, blood glucose levels and metabolism
    - - bones are made up of osseous tissue as well as nervous tissue, cartilage, fibrous connective tissue, muscle cells, epithelial cells and blood vessels.
      - 3 levels of structure
        
        gross anatomy
        
        microscopic anatomy
        
        chemical composition:
        organic and inorganic
        
        organic components:
        
        includes cells and osteoid
        
        allow tension resistance
        
        resilience of bone is in part due to bonds between collagen molecules that stretch and break to dissipate energy and prevent bone damage
        
        osteoid:
        organic part of matrix secreted by osteoblasts and consists of collagen fibers and ground substance
        
        inorganic components:
        
        allows for compression resistance
        
        remains long after the body had died due to mineral make-up
        
        made of hydroxyapatites which are mineral salts
        *65% of bone by mass is inorganic components
        
        compact bone
        consists of:
        
        osteon
        
        canals & canaliculi
        
        interstitial and circumferential lamellae
        
        osteon:
        
        structural unit of compact bone consisting of elongated cylinder that runs parallel to long axis of bone
        
        osteon cylinder composed of multiple rings of lamellae
        
        lamellae:
        
        contains collagen fibers running in different directions in adjacent rings
        
        resists twisting stress
        
        bone salts located between collagen fibers
        
        canals & canaliculi
        
        central canal:
        runs through osteon core
        contains blood vessels and nerve fibers
        
        perforating canals:
        located at right angles to central canal
        connects vessels and nerves of periosteum, medullary cavity and central
        
        lacunae:
        small cavities where osteocytes live
        
        canaliculi:
        thin hair-like canals connecting lacunae to each other and to central canal
        
        interstitial & circumferential lamellae
        
        interstitial lamellae:
        (not part of osteon)
        either fill gaps between forming osteons or is a remnant from a remodeled portion of bone
        
        circumferential lamellae:
        directly under periosteum and superfical to endosteum.
        extend around entire surface of diaphysis
        help prevent twisting of long bones
        
        spongy bone
        
        porous spaces are specifically organized to resist stress and withstand different pressures on bones
        
        "pores" are present due to organized network of trabeculae
        
        trabeculae contain irregularly arranged lamellae and osteocytes interconnected by canaliculi
        
        endosteum supplies nourishing capilaries
        
        compact bone:
        dense outer layer on every bone that appears smooth and solid
        
        spongy bone:
        honey-comb network of small flat branches of bone called trabeculae
        
        open spaces between trabeculae are filled with red or yellow bone marrow
        
        structure of short, irregular and flat bones
        
        diploe: thin plates of spongy bone covered by compact bone
        
        in compact bone:
        periosteum covers outside surfaces
        **endosteum covers inside surfaces
        
        bone marrow is scattered throughout spongy bone
        
        hyaline cartilage covers articulation surfaces
        
        bone membranes
        
        periosteum:
        
        white, double-layered
        
        contains nerves and blood vessels
        
        covers all external bone surfaces besides joints
        
        outer layer of dense connective tissue
        
        osteogenic layer inner layer. contains osteogenic stem cells that produce more bone cells
        
        anchoring for for tendons and ligaments
        
        endosteum:
        
        delicate connective tissue
        
        covers internal bone surface
        
        lines canals that pass through compact bone
        
        contains osteogenic cells that can become other bone cells
        
        structure of long bones
        
        diaphysis
        
        epiphyses
        
        ends of long bones
        compact bone externally
        spongy bone internally
        
        epiphyseal line:
        remnant of epiphyseal plate where bone growth occures in childhood
        
        located between diaphysis and epiphysis
        
        long tubular shaft of bone
        
        contains medullary cavity filled with yellow bone marrow (in adults)
        
        hematopoietic tissue in bone:
        
        yellow bone marrow can convert to red bone marrow when RBC count is low
        
        red bone marrow
        
        in newborns: all cavities (medullary and spongy bone spaces) contain red marrow
        
        in adults: red bone marrow found in heads of limb bones, flat bone diploe (most active in hematopoetic) and some irregular bones
        
        can be transplanted from a donor into a patient with bone marrow issue. injected into blood stream and find their way to appropriate locations for marrow
        
        bone markings
        (3 main categories):
        
        1) projections that allow muscle and ligament attachment
        
        2) surfaces for joints
        
        3) depressions and openings for vessels and nerves
        
        1 more item...
        
        head
        
        facet
        
        condyle
        
        tuberosity
        
        crest
        
        trochanter
        
        line
        
        tubercle
        
        epicondyle
        
        spine
        
        process
    - - osteogenic cells
        (aka osteoprogenitor cells)
        
        osteoblasts
        
        osteocytes
        
        osteoclasts
        
        large multi-nucleated cells whose function is to breakdown and reabsorb bones
        derived from hematopoietic stem cells that become macrophages
        
        mature bone cells located in lacunae
        
        no longer undergo mitosis
        
        maintain bone matrix
        
        communicate with other bone cells to aid in bone remodeling
        
        bone forming cells that secrete an unmineralized bone matrix (osteoid)
        
        Osteoid is made of collagen fibers and calcium-binding proteins.
        (collagen makes up 90% of bone protein)
        
        stem cells in the membranes surrounding internal and external bone that are actively undergoing mitosis.
        differentiate into osteoblasts when stimulated
    - - bony skeleton begins to form within 2 months of development
        
        postnatal bone growth occurs into late adolescence and stops at early adulthood
        
        the repair and remodeling of bones is an ongoing process throughout life
        
        postnatal bone growth:
        
        long bones grow longer via interstitial growth of epiphyseal plate
        
        bones grow thicker via appositional growth
        
        bones cease growth near early adulthood
        
        long bone lengthening:
        
        chondroblast division decreases towards end of adolescence
        
        cartilage epiphyseal plate things and becomes bone known as the epiphyseal line
        
        epiphysis and diaphysis fuse
        
        bone lengthening decreased in early adulthood (sex-dependent)
        
        bone thickening growth:
        
        bones increase width via appositional growth
        
        stress from weight and muscle activity stimulates bone thickening
        
        osteroblasts beneath periosteum secretes bone matrix on external surfaces with osteoclasts remove bone from inner surfaces
      - formation of bony skeleton:
        endochondral ossification
        vs.
        intramembranous ossification
        
        endochondral ossification:
        
        bone replaces hyaline cartilage and become endochondral bones
        
        how most of the skeleton forms
        
        5 step process
        
        1)
        bone collar forms around diaphysis of cartilage model
        
        2)
        central cartilage in diaphysis calcifies and dies creating cavities
        
        3)
        periosteal bud invades cavities forming spongy bone
        
        2 more items...
        
        intramembranous ossification:
        
        bone develops from fibrous connective tissue membrane formed by mesenchymal cells
        
        forms: frontal, parietal, occipital, temporal and clavicle bones
        
        4 step process
        
        1)
        ossification centers form when mesenchymal cells come together to become osteoblasts
        
        2)
        osteoid is secretes and calcified
        
        3)
        osteoid is wrapped around blood vessels forming trabeculae
        (outer layer of spongy bone forms periosteum)
        
        1 more item...
    - - bone remodeling
        
        bone deposit + bone resorption
        
        occurs on surfaces of periosteum and endosteum
        
        groups of adjacent osteoblasts and osteoclasts coordinate the process
        
        occurs at different rates depending on bone and part of bone
        
        bone resorption
        
        function of osteoclasts
        
        enzymes and digestive products break down matrix
        
        osteoclasts undergo apoptosis once resorption is complete
        (osteoclast activation involves **parathyroid hormone and immune T cell proteins)
        
        bone deposit
        
        function of osteoblasts
        REQUIRES:
        vitamin d
        vitamin c
        calcium
        phosphate
      - control of remodeling
        
        hormonal controls
        I
        V
        parathyroid hormone:
        produced by parathyroid glands in response to low blood calcium levels
        
        stimulates osteoclasts to resorb bone
        
        calcium released into blood stream to raise blood calcium levels
        
        when blood calcium reaches homeostatic levels, secretion of parathyroid cease.
        
        = determines IF and WHEN remodeling occurs
        
        response to mechanical stress:
        bearing weight and muscle pulling causes stress to bones.
        bone adjusts to these stresses via growth and remodeling
        stress is usually off-center so bones curve to compensate
        
        = determines WHERE remodeling occurs
    - - fractures classifications
        
        a) position of bone ends after fracture
        
        nondisplaced = ends in appropriate position
        vs.
        displaced = ends are out of alignment
        
        b) completeness of break
        
        complete = bone broken all the way through
        vs.
        incomplete = bone partially broken
        
        c) whether skin is penetrated or not
        
        open/compound = skin is penetrated
        vs.
        closed/simple = no penetration
      - fraction types:
        
        comminuted
        
        spiral
        
        depressed
        
        compression
        
        epiphyseal
        
        greenstick
      - treatment and repair
        
        reduction:
        realigning of broken bone ends
        closed reduction:
        physical manipulation to return to correct position
        open reduction:
        patient undergoes procedure to have pins and wires secure internally
        
        immobilization:
        use of a cast of traction to help bone heal appropriately
        
        STAGES OF FRACTURE REPAIR
        
        1) hematoma formation:
        damaged blood vessels hemorrhage which forms a internal mass of clotted blood called a hematoma
        
        2) fibrocartilaginous callus formation:
        
        capillaries grow into hematoma
        
        fibroblasts, cartilage, osteogenic cells and osteoblasts reconstruct bone
        
        the mass of tissue made is the fribrocartilaginous callus
        
        3) bony callus formation:
        
        within the first week new trabeculae are made in the fibrocartilaginous callus which is converted into a bony callus of spongy bone
        
        4) bone remodeling:
        
        osteoclasts remove excess bony material
        
        compact bone begins to reconstruct diaphysis walls
        
        final structure very similar to original because it will most likely have to respond to the same stressors
  - - - protects, supports and carries other body parts
    - - allows movement of body from place to place and allows manipulation of environment
  - - - short bones
        
        flat bones
        
        irregular bones
        
        complicated shapes
        
        vertebrae and hip bones
        
        thing, flat, curved
        
        sternum, scapulae, ribs, most skull bones
        
        sesamoid bones
        
        short roundish bones within tendons
        
        cube-shaped
        
        wrist and ankle bones
      - longer than they are wide
        
        limb bones
- - - - bony callus formation:
        
        new trabeculae form in the fribrocartilaginous callus within a week
        
        converted to bony callus of spongy bone
        
        bone remodeling:
        
        excess bone material removed by osteoclasts
        
        shaft walls are reconstructed with compact bone
        
        without complications, bone should eventually return to it's normal structure since it should be remodeling/responding to the same mechanical stressors it underwent prior to the fracture
        
        If the patient does not change their lifestyle in such a way that the appropriate vitamins and minerals required for a healthy skeletal system are obtained regularly then the bones will heal and still be as fragile as the were before the accident
        
        If the patient makes lifestyle changes such as ingesting calcium rich foods of taking daily supplements, then all his bones including his right arm will gradually become stronger than they were prior to this accident
  - - - especially as he ages because all skeletal systems, even healthy ones, begin to degrade and become less strong and resilient with time
        
        other age-related changes he will experience in older age will exacerbate the issues/