Musculoskeletal patho

• osteoclasts


  digest the bone within a sealed resorption vacuole
• osteoblasts


  build bone / osteoid tissue

  mineralization
• resorption


  removal of bone by breakdown and absorption into the circulation
• bone mineralization/ formation chemicals

  OPG

  TGF-B

  estrogen
• resorption signals

  GM-CSF

  IL-1

  IL-6

  inflammation cytokines help with bone resorption
• cartilage


  provides cushion
• bursa


  produces synovial fluid

  connected to joint itself
• How does aging affect bones?

  Bones become less dense, less strong, and brittle.
• How does aging affect joints?

  Cartilage becomes rigid, fragile, and susceptible to injury/fraying due to decreased water content. Tendons shrink and harden.DEHYDRATED
• How does aging affect muscles?

  Musclesremain trainablebut there isreduced RNA synthesisandloss of mitochondrial function.
• Types of Injuries

  Sprains and strains

  Muscle contusions

  Bone fractures

  Soft tissue injury Neurovascular injury Compartment syndrome Rhabdomyolysis

  DVT and pulmonary embolism

  Fat embolism

  Avascular necrosis
• ligament vs tendon

  ligament- bone to bone

  tendon- muscle to bone
• What is a sprain?

  An overstretching or tearing of a ligament, commonly occurring around joints like the ankle.
• What is a

  strain?An overstretching oftendons and muscles, common in areas like the lower back and hamstring.
• Muscle Contusions

  A bruise occurs when muscle and connective tissues are crushed. Torn blood vessels may result in bluish discoloration (de-oxygenated blood)issue with muscle and connective tissue
• Types of Bone Fractures

  Closed; Open (compound) ;Transverse; Spiral Avulsion ;Comminuted; Compression ;Greenstick; Stress; Pathological
• Open and Closed Fractures

  Is the skin broken? Relative risk of infection

  open: bone is visible

  closed: bone is not visible
• What is a transverse fracture?

  A clean horizontal closed fracture
• What is a spiral fracture?

  When a bone breaks in a spiral segment
• What is an avulsion fracture?

  It occurs around major joints (like knees) where the bone, to which the tendon is connecting, breaks off, leading to extreme joint instability and possible buckling of the knee
• comminuted fracture

  fracture in which the bone is splintered or crushedmany bone fragmentsneeds artificial to make up for that gapRequires titanium plate and screwsMay need bone graft
• compression fracture


  occurs when the bone is pressed together (compressed) on itself consequence of osteoporosis loss of bones -> pressure compresses on the vertebral bodies and causes them to fracture poor bone density treatment: strengthen vertebral bodies via vertebroplasty
• greenstick fracture

  bending and incomplete break of a bone; most often seen in children
• stress fracture


  a small crack in the bone that often develops from chronic, excessive impactfractures from high levels of stress often from susceptible bones
• pathological fracture

  break in a bone weakened by some other diseasebone is already weakened like for example from a tumor (malignancy or metastatic deposit) to make bone unstable so the bone fractures spontaneouslyexamples of tumors that metastasize to bone: lung, prostate, breast
• pelvic fracture

  Car crashes in younger

  Falls in elderly

  Can result in serious hemorrhage -> can knick or cut a vessel

  "a leading cause of killing old ladies"
• Soft Tissue Injury

  swelling

  Along side fracture

  Can happen in isolation(contusion - tissue is crushed between outside force and a bone)

  Generally, swelling and redness is to keep us from using an injured body part
• Neurovascular Injuries


  Done by displaced bone due to fracture or dislocation OR the force that caused the injury
• What is Compartment Syndrome?

  Tissue pressure exceeds perfusion pressure
• How are muscles contained in Compartment Syndrome?

  Muscles are contained within a fascial membrane
• treatment of compartment syndrome

  fasciotomy: making an incision through the tough membrane surrounding the muscles (fascia) to restore blood flow and prevent tissue damage
• What happens during Rhabdomyolysis?

  Breakdown of skeletal muscle releases myoglobinwhich istoxic to nephronskidney damage could lead to death -> need hydration to flush it out
• How long can muscle withstand compartment syndrome before irreversible damage occurs

  Irreversible damage occurs within 6 hours due to the limitation of swelling and/or bleeding
• What are some complications associated with orthopedic injuries or surgeries?

  DVT, pulmonary embolism, fat embolism, avascular necrosis
• Which specific type of injury can lead to fat embolism?

  Fracture of long bones such as the femur
• What is avascular necrosis?

  Insufficient blood supply leading tobone necrosisdead tissue = playground for bacteria to get there
• thrombus


  stationary clot
• embolus

  mobile clot that travels then blocks
• osteoporosis


  porous bone / bone lossComplex, multifactorial, chronicDecreased bone densityResporption gets favored so bone gets broken down at a faster rate than bone gets built
• osteoporosis risk factors

  More common in Asians and whitessmokingwomen more susceptible than men- women who have low BMIexcessive alcoholpeople who take chronic glucocorticosteroids bc accelerates osteoclast activityvitamin D deficiencyLow estrogen levels can lead to an increase in the activity of osteoclasts, the cells responsible for breaking down bone tissueanything chronically being treated by steroids(autoimmune, asthma)