Mechanisms and Characteristic of Nerve Trauma

  • Trauma
    • Physical injury or wound that is produced by an external or internal force
    • Mechanical Injury - force or mechanical energy is that which changes that state of rest or uniform motion of matter
    • When a force applied to any part of the body results in a harmful disturbance in function and/or structure - a mechanical injury occurs
  • 5 Types of Tissue Loading
    • Compression - shortens and widens tissue
    • Tension - pulls or stretches tissue
    • Shearing - rubbing (blisters)
    • Bending - tension and compression
    • Torsion - twisting 
  • Traumatic vs. Overuse Injuries
    • Injuries are either caused by trauma or overuse
    • All  injuries are acute, if the injury does not heal properly it becomes chronic 
    • Injuries that result from overuse occur with the repetitive dynamics of running, throwing, or jumping
  • Anatomical Characteristics of Muscles
    • Muscle → Fascicles → Muscle fibers (cells) → Myofibrils → Thick and thin filaments
    • Muscle: Tissue of the body which primarily functions as a source of power
    • Responsible for moving extremities and external areas of the body are called skeletal muscle
  • Muscle Strains
    • When a muscle is overstretched by tension or forced to contract against too much resistance, separation or tearing of the muscle fibers occurs. 
    • A muscle strain can be a stretch, tear or rip in the muscle or its tendon. 
    • Grade 1: some muscle fibers have been stretched or torn
    • Grade 2: a number of muscle fibers have been torn 
    • Grade 3: a complete rupture of the muscle has occurred
  • Muscle Cramps
    • Extremely painful involuntary muscle contractions that occur commonly in the calf, abdomen or hamstrings
    • Heat cramps is related to excessive loss of water and some extent several electrolytes or ions that are essential elements in muscle contraction
  • Muscle Guarding 
    • Muscle contracting in response to pain
    • Body’s defense mechanism to act as a splint 
  • Muscle Spasms
    • A reflex reaction caused by trauma to the musculoskeletal system
    • Clonic - involuntary muscle contraction characterized by alternate contraction and relaxation in rapid succession
    • Tonic- muscle contraction characterized by constant contraction that lasts for a period of time 
  •  Muscle Soreness
    • Pain caused by overexertion in exercise 
    • Acute onset muscle soreness - fatigue, occurs immediately after exercise  
    • Delayed onset muscle soreness (DOMS) - increased muscle tension, swelling, and stiffness
      • causes include small tears in the muscle tissue or disruption in connective tissue that holds muscle tendon fibers together
  • Anatomical Characteristics of Tendons  
    • Tough band of connective tissue that attaches muscle to bone
    • Concentrates a pulling force in a limited area
    • Because a tendon is usually double the strength of the muscle it serves, tears commonly occur at the muscle belly, musculotendinous junction or bony attachment 
  • Tendinitis/Tendinosis
    • Tendinitis- inflammation of the tendon
    • Moves or slides on the other structures around it whenever the muscle contracts, if the movement is performed repeatedly the tendon can become irritated and inflamed
    • Crepitus - a crackling feel or sound that occurs by tendon’s tendency to stick to the surrounding structure while it slides back and forth 
    • Tendinosis - breakdown of a tendon without inflammation (degeneration)
    • Tenosynovitis - inflammation of a tendon and its synovial sheath (thin layer of tissue)
  • Contusion
    • Compression of soft tissue that results in bleeding into surrounding tissue
    • Ecchymosis - bluish-purple discoloration of the skin 
  • Joints
    • A point where two bones interest
    • Necessary for all types of movement in the body involving bones
    • The force generated by muscles is used to carry out movement through various joints 
    • Synovial joints
    • Articulations of two bones surrounded by a joint capsule lined with synovial membrane
    • Bursitis: inflammation of bursae (pieces of synovial membrane that contain a small amount of fluid)  at sites of bony prominences between muscle and tendon
  • Dislocations and Subluxations
    • Dislocation occurs when at least one bone in a joint is forced completely out of its normal alignment 
    • Subluxation is like a dislocation except that a bone comes partially out of its normal articulation then goes right back into place
  • Anatomical Characteristics of Ligaments
    • Ligaments are composed of dense connective tissue arranged in parallel bundles of collagen composed of rows of fibroblasts 
    • Ligaments connect bone to bone
  • Ligaments Sprains
    • Occur when stress is applied to a joint that forces motion beyond its normal limits or planes of movement
    • Grade 1 Sprain - stretch or separation 
    • Grade 2 Sprain - tearing and separation with instability 
    • Grade 3 Sprain - total tear of ligament which leads to instability of joint
  • Classification and Load Characteristics of Injuries

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