skeletal system

• 206 bones in the adult body

• axial & appendicular

  • axial = connected to the vertebrae / spinal column (skull, spine, ribs, & sternum)

  • appendicular = branching off axial (shoulder & pelvic girdles & attached limb bones)

• functions

  • body mvmnt

  • supports & protects internal body organs

  • produces red & white blood cells

  • provides a storehouse for minerals

• bones made of osteocytes (mature bone cells)

  • 35% organic material

  • 65% inorganic mineral salts & water

  • osteoclasts = break down

  • osteoblasts = build up

• formation

  • initially collagenous protein fibers secreted by osteoblasts

  • cartilage deposited btwn fibers

  • ossification begins & bone formed

• long bone structure

  • epiphysis = ends

  • shaft/diaphysis = middle

  • epiphysis & diaphysis divided by growth plate (open growth plate = still growing)

  • bone marrow w/i diaphysis medullary cavity

  • periosteum = outer covering of diaphysis

• bone types

  • long = upper & lower arms & legs

  • short = cube-like

  • flat = skull & ribs

  • irregular = spinal column

  • most flat bones are also irregular

• degree of mvmnt at joint based on bone shape & joint structure

• fractures can be classified by degree of injury to bone

  • simple or closed = not breaking through skin

  • compound or open = fractured end penetrates skin & causes danger of infection

  • greenstick = mostly children bc bones are more flexible/malleable

  • comminuted = bone shatters in three or more places

  • stress = overuse, poor muscle balance, lack of flexibility, weakness in soft tissue caused by previous injuries, gradual deterioration of bones

  • epiphyseal plate = more often in children ages 10-16 form sport participation

• fracture signs & symptoms

  • not all fractures show deformity

  • swelling, deformity, pain, tenderness, & discoloration

• treatment

  • bones must be put back in proper position (reduction)

  • immobilization w/ cast (external fixation)

  • surgery (internal fixation)