Kin 188 Mechanisms And Types Of Injuries


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Kin 188 Mechanisms And Types Of Injuries

  1. 1. KIN 188 – Prevention and Care of Athletic Injuries Mechanisms and Types of Injuries Terminology
  2. 2. Introduction <ul><li>Injury mechanisms </li></ul><ul><li>Soft tissue injuries </li></ul><ul><li>Bone injuries </li></ul><ul><li>Nerve injuries </li></ul>
  3. 3. Injury Mechanisms <ul><li>Force and its effects </li></ul><ul><li>Torque and its effects </li></ul>
  4. 4. Force <ul><li>Force is a push or pull acting on the body </li></ul><ul><li>There are 2 potential effects of force application </li></ul><ul><ul><li>Acceleration or change in velocity </li></ul></ul><ul><ul><li>Deformation or change in shape </li></ul></ul><ul><ul><ul><li>Greater stiffness of material = less likelihood that deformation will be seen </li></ul></ul></ul><ul><ul><ul><li>Greater elasticity of material = more likelihood that deformation will be temporary </li></ul></ul></ul>
  5. 5. Force <ul><li>When tissues exposed to force, 2 factors determine whether or not injury will occur </li></ul><ul><ul><li>Size or magnitude of force </li></ul></ul><ul><ul><li>Material properties of involved tissues </li></ul></ul>
  6. 6. Force <ul><li>Load deformation curve </li></ul><ul><li>With small loads, response of tissue is elastic </li></ul><ul><ul><li>When load removed, material returns to normal shape and size </li></ul></ul><ul><ul><li>Within elastic region, greater material stiffness leads to a steeper slope of the line </li></ul></ul><ul><li>With higher loads (exceeding yield point of material), response is plastic </li></ul><ul><ul><li>When load removed, some amount of deformation will remain </li></ul></ul><ul><ul><li>Loads exceeding ultimate failure point of material result in mechanical failure of the tissue </li></ul></ul>
  7. 7. Load-Deformation Curve
  8. 8. Force <ul><li>Direction of force application also has injury implication potential </li></ul><ul><li>Many tissues are anisotropic – better able to resist force from certain directions that others </li></ul><ul><li>Force acting along long axis of structure is axial force </li></ul><ul><ul><li>Axial loading producing a crushing/squeezing effect is called compressive force </li></ul></ul><ul><ul><li>Axial loading opposite compressive forces is called tensile force </li></ul></ul><ul><li>Force acting parallel to plane passing through structure is shear force </li></ul>
  9. 9. Compression, Tension and Shear
  10. 10. Force <ul><li>Stress </li></ul><ul><ul><li>Magnitude of stress produced by force application also factors into injury mechanism </li></ul></ul><ul><ul><li>Stress is force divided by surface area over which the force is applied </li></ul></ul><ul><ul><li>When given force distributed over large area, resulting stress is less than if force were concentrated over smaller area and vice versa </li></ul></ul><ul><ul><li>High magnitude of stress, rather than high magnitude of force, tends to result in injury to tissue </li></ul></ul>
  11. 11. Stress
  12. 12. Force <ul><li>Strain </li></ul><ul><ul><li>Amount of deformation a structure undergoes in response to an applied force </li></ul></ul><ul><ul><li>Compressive forces produce shortening and widening of structure </li></ul></ul><ul><ul><li>Tensile forces produce lengthening and narrowing of structure </li></ul></ul><ul><ul><li>Shear forces result in internal changes in structure </li></ul></ul><ul><ul><li>Ultimate strength of tissues determines amount of strain a structure can withstand before being injured </li></ul></ul>
  13. 13. Torque <ul><li>Generically thought of as a rotary force </li></ul><ul><li>Excessive torque in the body can produce injury </li></ul><ul><ul><li>Simultaneous application of forces from opposite directions at different points along a structure generates torque known as bending moment – compression on one side and tension on the other </li></ul></ul><ul><ul><li>Application of torque about the long axis of a structure causes torsion (twisting) which results in shear forces throughout the structure </li></ul></ul>
  14. 14. Torque
  15. 15. Soft Tissue Injuries <ul><li>Skin injuries </li></ul><ul><li>Contusions </li></ul><ul><li>Strains </li></ul><ul><li>Sprains </li></ul><ul><li>Cramps/spasms </li></ul><ul><li>Myositis/fasciitis </li></ul><ul><li>Tendinitis and tenosynovitis </li></ul><ul><li>Myositis ossificans </li></ul><ul><li>Bursitis </li></ul>
  16. 16. Skin Injuries <ul><li>Abrasions </li></ul><ul><ul><li>Shear injuries occurring when skin scraped, usually in one direction, against a rough surface </li></ul></ul><ul><li>Blisters </li></ul><ul><ul><li>Caused by repeated applications of shear forces in one or more directions with formation of fluid pocket between dermis and epidermis </li></ul></ul><ul><li>Incisions </li></ul><ul><ul><li>Clean cut produced by application of tensile force to skin as it’s stretched along a sharp edge </li></ul></ul>
  17. 17. Skin Injuries <ul><li>Lacerations </li></ul><ul><ul><li>Irregular tear in skin typically resulting from a combination of tension and shear forces </li></ul></ul><ul><li>Avulsions </li></ul><ul><ul><li>Severe laceration resulting in complete separation of skin from underlying tissue </li></ul></ul><ul><li>Punctures </li></ul><ul><ul><li>Results when sharp, cylindrical object penetrates the skin with tensile loading </li></ul></ul>
  18. 18. Contusions <ul><li>Commonly referred to as bruises </li></ul><ul><li>Result from direct compressive forces </li></ul><ul><li>Severity based upon area and depth over which blood vessels are ruptured </li></ul><ul><ul><li>Mild – little or no ROM restriction </li></ul></ul><ul><ul><li>Moderate – noticeable reduction in ROM </li></ul></ul><ul><ul><li>Severe – may rupture associated fascia causing muscle tissue to protrude from injured area </li></ul></ul><ul><li>Ecchymosis - discoloration </li></ul><ul><li>Hematoma – hard mass composed of blood and dead tissue at site of trauma </li></ul>
  19. 19. Strains/Sprains <ul><li>Strains occur to muscles and tendons </li></ul><ul><li>Sprains occur to ligaments and joint capsules </li></ul><ul><li>Typically occur from application of abnormally high tensile forces that damages the tissue </li></ul><ul><li>Most susceptible area of muscle/tendon injury is at/near musculotendinous junction </li></ul><ul><li>Most susceptible area of ligament/joint capsule is mid-substance (strongest near bony attachments) </li></ul>
  20. 20. Strains/Sprains <ul><li>Strains and sprains categorized as first, second or third degree injuries </li></ul><ul><li>First degree (mild) </li></ul><ul><ul><li>Microtrauma with minimal associated symptoms </li></ul></ul><ul><li>Second degree (moderate) </li></ul><ul><ul><li>Partial tearing of tissue, detectable weakness and joint instability </li></ul></ul><ul><li>Third degree (severe) </li></ul><ul><ul><li>Complete rupture of tissue, loss of ROM and joint stability </li></ul></ul>
  21. 21. Cramps/Spasms <ul><li>Painful, involuntary muscle contractions </li></ul><ul><li>Cramps appear to be brought on by biochemical imbalance and/or muscle fatigue </li></ul><ul><li>Spasms can be caused by biochemical action or secondary to trauma (natural splinting mechanism) </li></ul>
  22. 22. Myositis/Fasciitis <ul><li>Inflammation of muscle connective tissue (myositis) or inflammation of sheaths of fascia surrounding portions of muscle (fasciitis) </li></ul><ul><li>Develop over time from repeated stresses that irritate those tissues </li></ul>
  23. 23. Tendinitis/Tenosynovitis <ul><li>Tendinitis </li></ul><ul><ul><li>Inflammation of tendon itself – little blood supply </li></ul></ul><ul><ul><li>Associated with degenerative changes in tendon (tendinosis) </li></ul></ul><ul><li>Tenosynovitis </li></ul><ul><ul><li>Inflammation of tendon sheath – highly vascular </li></ul></ul><ul><ul><li>If acute, often accompanied by crepitus and swelling </li></ul></ul><ul><ul><li>If chronic, of presents with nodule formation in sheath </li></ul></ul>
  24. 24. Overuse Injuries <ul><li>Typically classified in four stages </li></ul><ul><ul><li>Stage 1: pain after activity only </li></ul></ul><ul><ul><li>Stage 2: pain during activity, does not restrict performance </li></ul></ul><ul><ul><li>Stage 3: pain during activity, restricts performance </li></ul></ul><ul><ul><li>Stage 4: chronic, unremitting pain, even at rest </li></ul></ul>
  25. 25. Myositis Ossificans <ul><li>Accumulation of mineral deposits in muscle (ectopic calcification) secondary to prolonged chronic inflammation </li></ul><ul><li>If occurs in tendons, referred to as calcific tendinitis </li></ul><ul><li>Common site is quadriceps muscle group secondary to moderate or severe contusion </li></ul><ul><li>Hardened mass often palpable and can be visualized on x-ray after ~3 weeks </li></ul>
  26. 26. Bursitis <ul><li>Irritation of fluid-filled sacs that serve to reduce friction in the tissues surrounding joints </li></ul><ul><li>May be associated with single traumatic event or secondary to repeated applications of stress with overuse conditions </li></ul><ul><li>Common to olecranon area (elbow) and pre-patellar area (knee) </li></ul>
  27. 27. Bone Injuries <ul><li>Fracture – disruption in continuity of a bone </li></ul><ul><li>Type of fracture depends upon type of mechanical loading that caused it as well as on health of bone at the time of injury </li></ul><ul><li>Closed fracture – bone ends remain intact within surrounding soft tissue </li></ul><ul><li>Open/compound fracture – one or both bone ends protrudes from the skin </li></ul>
  28. 28. Fracture Types <ul><li>Depressed </li></ul><ul><ul><li>Broken bone portion driven inward – most common on flat bones of skull </li></ul></ul><ul><li>Transverse </li></ul><ul><ul><li>Break in straight line across axis of bone </li></ul></ul><ul><li>Comminuted </li></ul><ul><ul><li>Bone fragments into several pieces </li></ul></ul><ul><li>Oblique </li></ul><ul><ul><li>Break diagonally across axis of bone </li></ul></ul>
  29. 29. Fracture Types <ul><li>Spiral </li></ul><ul><ul><li>S-shaped fracture from torsion forces </li></ul></ul><ul><li>Greenstick </li></ul><ul><ul><li>Incomplete fractures – children (like green stick) </li></ul></ul><ul><li>Avulsion </li></ul><ul><ul><li>Bone fragment pulled off by attached ligament or tendon </li></ul></ul><ul><li>Impacted </li></ul><ul><ul><li>Bone driven into another bone causing injury </li></ul></ul>
  30. 30. Fracture Types
  31. 31. Fracture Types <ul><li>Stress fractures (aka “fatigue fractures”) </li></ul><ul><ul><li>From repeated low-magnitude forces (overuse injury) </li></ul></ul><ul><ul><li>Worsen over time if untreated </li></ul></ul><ul><ul><li>Begin as small disruption in continuity of outer layer of bone and can progress to through fracture with or without displacement </li></ul></ul><ul><ul><li>Most common in metatarsals, tibia, femoral neck, pubis bone, pars interarticularis of spine segments </li></ul></ul>
  32. 32. Fracture Types <ul><li>Epiphyseal injuries (Salter classifications) </li></ul><ul><ul><li>Type I: complete separation of epiphysis from metaphysis with no fracture to bone </li></ul></ul><ul><ul><li>Type II: separation of epiphysis and a small portion of the metaphysis </li></ul></ul><ul><ul><li>Type III: fracture of the epiphysis </li></ul></ul><ul><ul><li>Type IV: fracture of a part of the epiphysis and metaphysis </li></ul></ul><ul><ul><li>Type V: compression of the epiphysis without fracture resulting in compromised epiphyseal function </li></ul></ul>
  33. 33. Epiphyseal Fractures
  34. 34. Nerve Injuries <ul><li>Tension vs. compression </li></ul><ul><li>Tensile injury grades </li></ul><ul><li>Compression considerations </li></ul><ul><li>Symptoms of nerve injuries </li></ul>
  35. 35. Tension vs. Compression <ul><li>Tensile nerve injuries typically associated with high-speed impacts/collisions in contact sports </li></ul><ul><li>Nerve roots particularly susceptible to tensile forces – cervical spine/brachial plexus “stingers” </li></ul><ul><li>Compressive forces “pinch” on nerves </li></ul><ul><ul><li>Direct – mechanical force on nerve tissue </li></ul></ul><ul><ul><li>Indirect – pressure from swelling in associated area </li></ul></ul>
  36. 36. Tensile Injury Grades <ul><li>Grade I – neuropraxia </li></ul><ul><ul><li>Temporary loss of sensation/motor function without axon disruption </li></ul></ul><ul><ul><li>Typically resolves in a few days to a few weeks </li></ul></ul><ul><li>Grade II – axonotmesis </li></ul><ul><ul><li>Significant motor and mild sensory function loss from axon disruption </li></ul></ul><ul><ul><li>Typically lasts at least a couple of weeks </li></ul></ul><ul><li>Grade III – neurotmesis </li></ul><ul><ul><li>Complete rupture of nerve tissue with associated motor and sensory deficits that are typically permanent </li></ul></ul>
  37. 37. Compression Considerations <ul><li>Severity of nerve compression injury dependent upon magnitude and duration of loading and on whether the applied compression is direct or indirect </li></ul><ul><li>Nerve function highly dependent upon oxygen, so associated vascular injury caused by compressive injury results in further damage to the nerve </li></ul>
  38. 38. Symptoms of Nerve Injuries <ul><li>Hypoesthesia </li></ul><ul><ul><li>Altered sensation of nerve </li></ul></ul><ul><li>Hyperesthesia </li></ul><ul><ul><li>Heightened sensitivity of nerve </li></ul></ul><ul><li>Paresthesia </li></ul><ul><ul><li>Numbness, prickling, tingling sensations </li></ul></ul><ul><li>Neuralgia </li></ul><ul><ul><li>Chronic pain along nerve distribution/path secondary to irritation and/or inflammation </li></ul></ul>
  39. 39. Terminology
  40. 40. Anatomic Position
  41. 41. Planes of the Body <ul><li>Sagittal </li></ul><ul><ul><li>Separates into left and right segments </li></ul></ul><ul><li>Frontal/coronal </li></ul><ul><ul><li>Separates into anterior and posterior segments </li></ul></ul><ul><li>Transverse </li></ul><ul><ul><li>Separates into superior and inferior segments </li></ul></ul>
  42. 42. Terminology <ul><li>Anterior – toward front of body </li></ul><ul><li>Posterior – toward back/rear of body </li></ul><ul><li>Superior (cephal) – toward head </li></ul><ul><li>Inferior (caudal) – toward “tail” </li></ul><ul><li>Proximal – closer to trunk </li></ul><ul><li>Distal – further from trunk </li></ul>
  43. 43. Terminology <ul><li>Medial – toward midline of body </li></ul><ul><li>Lateral – away from midline of body </li></ul><ul><li>Abduction – movement away from midline </li></ul><ul><li>Adduction – movement toward midline </li></ul><ul><li>Pronation – foot: lowering medial arch, hand: turning palm down </li></ul><ul><li>Supination – foot: raising medial arch, hand: turning palm up </li></ul>
  44. 44. Terminology <ul><li>Flexion – to bend (joint angle increases) </li></ul><ul><li>Extension – to extend (joint angle decreases) </li></ul><ul><li>Internal rotation – rotary movement toward midline </li></ul><ul><li>External rotation – rotary movement away from midline </li></ul><ul><li>Varus – distal segment of body part toward midline </li></ul><ul><li>Valgus – distal segment of body part away from midline </li></ul>