system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Tinel sign is seen in ?
assistant
The correct answer is  Ans. is 'b' i.e., Nerve regeneration Pathological changes after nerve injury After nerve injury, nerve first degenerates and then tries to regenerate. Nerve degeneration The pa of the neurone distal to the point of injury undergoes secondary or Wallerian degeneration; the proximal pa undergoes primary or retrograde degeneration upto a single node. Nerve regeneration As regeneration begins, the axonal stump from the proximal segment begins to grow distally. If the endoneural tube with its contained Schwann cells is intact, the axonal sprout may readily pass along its primary course and reinnervate the end-organ. The rate of recovery of axon is 1 mm per day. The muscles nearest to the site of injury recovers first, followed by others as the nerve reinnervates muscles from proximal to distal, the so-called motor march. When the skin over the nerve is percussed gently from distal to proximal, the patient gets a tingling sensation if the nerve is recovering. This is called Tinel's sign and is a sign of recovery.