Sensory Examination Continued...


Large sensory fibers subserve discriminative touch, vibration sense and position sense (posterior columns/medial lemniscus system)
  • Large fibers are myelinated and conduct faster
  • Only large fibers can be evaluated with nerve conduction studies

Small sensory fibers subserve crude touch, pain and temperature (anterolateral system)
  • Lightly myelinated or unmyelinated axons that conduct more slowly
  • That is why is takes a few seconds before you feel the pain when you are injured
  • Autonomic fibers that are involved in urination, defecation, erection and maintenance of blood pressure on standing also travel with the small sensory fibers
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