Local & Regional Anaesthesia · NEET PG Preparation Anaesthesia
Which of the following nerve fibre types is blocked first by local anaesthetics, typically resulting in the earliest loss of sensation?
Practice question from Local & Regional Anaesthesia (NEET PG Preparation Anaesthesia), with the correct answer and a step-by-step solution.
easy · MCQ · Q-4882BC
Which of the following nerve fibre types is blocked first by local anaesthetics, typically resulting in the earliest loss of sensation?
- A.A-alpha fibres (motor and proprioception)
- B.A-beta fibres (touch and pressure)
- C.A-gamma fibres (muscle tone)
- D.B and C fibres (autonomic and pain/temperature)Correct answer
Solution
Small, unmyelinated C fibres (pain and temperature) and preganglionic B fibres are blocked first by local anaesthetics due to their small diameter and lack of myelin sheath (or thin myelination), leading to early loss of pain and temperature sensation before motor blockade.
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