Which of the following is most sensitive to the inhibition by local anesthetics -
Sensitivity of nerve fibres to inhibition by local anesthetics is determined by axonal diameter, myelination and other anatomical & physiological features. In comparing nerve fibers of the serve type smaller diameter increases sensitivity to local anesthetics. Thus larger Aa fibres less sensitive to local anesthetics then smaller, slower conducting As fibres. For sensitivity B>C=Adelta>Agama>Ab>Aa Most sensitive - Least sensitive for L.A. B>C>A Autonomic > Sensory > Motor Temperature (Cold) >Pain> Touch> proprioception Recovery from block is in opposite direction
B fibre
Dorsal root
As
Aa
Regional Anesthesia