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
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  • 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 
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• 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
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  • 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
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• 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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