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Fractured right elbow joint and humerus (Anatomy of long bones, micro to…

- - - - II. Growth: Interstitial Growth (Length)
        1. Zone of resting cartilage: Composed of small chondrocytes distributed throughout a cartilage matrix, this region secures the epiphysis to the epiphyseal plate.
        2. Zone of proliferating cartilage: Chondrocytes in this region undergo rapid mitosis and align into vertical columns of flattened lacunae parallel to the diaphysis.
        3. Zone of hypertrophic cartilage: Chondrocytes cease dividing and enlarge in size (hypertrophy). The walls of the lacunae thin as chondrocytes resorb bone matrix.
        4. Zone of calcified cartilage: Minerals are deposited in the matrix between columns of lacunae. Such calcification destroys the chondrocytes and makes the matrix appear opaque.
        5. Zone of ossification: Walls between lacunae break down, forming vertical channels. Channels invaded by capillaries and osteoprogenitor cells from medullary cavity. New matrix of bone deposited on remaining calcified matrix.
        
        III. Remodeling:
        Process of bone resorption followed by replacement, occurring throughout life. Regulates calcium homeostasis, repairs day-to-day damage, shapes skeleton during growth.
        1. Stimulation of osteoclasts, which break down peptide bonds in collagen and make bone matrix more soluble; breakdown releases calcium into circulation for use throughout body.
        2. Osteoblasts come to prominence once involved osteoclasts die, differentiating and layering osteoid (new bone matrix) at site of resorption.
        3. Osteocytes are activated on new bone's surface once osteoblasts differentiate.
        4. Mineralization with hydroxyapatite occurs, hardening bone. "Curing" takes several months.
      - II. Growth: Appositional Growth (Width)
        
        Osteoblasts beneath the periosteum secrete bone matrix, forming ridge that follow the course of periosteal blood vessels.
        
        As the bony ridges enlarge and meet, the groove containing the blood vessel forms a tunnel.
        
        Periosteum lining the tunnel transformed into endosteum; osteoblasts just deep to tunnel secrete bone matrix, narrowing the canal.
        
        Osteoblasts beneath the endosteum form layers (lamellae) and create new osteon. New circumferential lamellae on perimeter are elaborated beneath periosteum. Process is repeated, enlarging bone's diameter.
  - - - Raw Materials for Bone Growth & Repair:
        Calcium is primary mineral in hydroxyapatite, the substance which provides strength and hardness to osseous tissues.
        Vitamin C needed to produce collagen proteins, which form bones, tendons, cartilage and blood vessels.
        Vitamin D allows bones to absorb calcium from blood. Stimulates cells involved in bone formation.
        Vitamin K strengthens bones' osteocalcin, a protein component of bone.
        
        Additional Notes Re: Patient's Diet:
        Patient's diet consists of many processed foods. Picky eating and lactose intolerance has led to a calcium and nutrient deficiency.
        Impeded bone density, vitamin absorption, bone modeling and resorption; susceptible to additional injury and breakage well before old age and following recovery from injuries.
    - - Salter-Harris Classification:
        Type I: Slipped - Passes through growth plate, spares the bone.
        Type II: Above - Passes growth plate, affects metaphysis.
        Type III: Lower - Passes along growth plate, disrupts epiphysis.
        Type IV: Through/transverse - Fracture at growth plate, metaphysis and epiphysis together.
        Type V: Ruined/rammed - Growth plate impacted and crushed.
        
        Type IV:
        
        10% of all growth plate fractures; considered critical
        
        Occurs most commonly at the end of the humerus near the elbow
        
        Fracture runs through epiphysis, across growth plate and into metaphysis
        
        Surgery is needed to restore joint surface to normal and restore alignment of growth plate
        
        Unless perfect alignment is achieved and maintained during healing, prognosis for growth is poor
      - III. Open (or Compound):
        
        All open fractures should be considered to be contaminated
        
        Likelihood of bacterial entry dependent on severity of injury, damage to soft-tissues, and the environment where injury occurred
        
        Treatment of established bone infections often requires multiple surgeries, prolonged antibiotics and long-term problems.
        
        Orthopedic surgeons suggest surgery take place within six hours of injury
  - - - Organ level: Structures & Structural Accessories
        Periosteum: Protective fibrous membrane covering the bone. Serves as protection for bone and channel for blood supply. Plays major role in bone growth and repair.
        Endosteum: Structure in middle of bone tissue and marrow. Thin covering surrounding medullary cavity. Covers loose structures found inside bone. Houses osteoprogenitor cells, which differentiate into osteoblasts, matrix-secreting cells or bone-lining cells.
        Blood vessels: Supplies nutrients needed to maintain and repair. Runs through Haversian canals/canaliculi in comact bone and spongy bone's trabeculae.
        Nerves: Bones are innervated by peripheral nerves to coordinate with CNS. Brain reads bone nerves' signals to avoid damage to bones and inner/adjacent tissues. Aligned with veins and arteries.
        Red bone marrow: Produces blood cells; contains mostly erythrocytes, leukocytes and platelets. Newly produced BCs enter bloodstream via sinusoid vessels. At birth almost all marrow is red. Found in handful of bones, including skull, vertebrae, sternum, ribs and end of humerus.
        Yellow bone marrow: Made of fat and salts, stored in medullary cavity in bone's center. Body uses to develop bone, fat, cartilage, muscle or as emergency nutrient supply.