Fig. 2. Ultrasound images illustrating the in-plane needle positioning (  arrowheads ) to place the needle tip (  dashed arrows ) (  A ) first in the extraneural compartment and then (  B ) into the intraneural space of the longitudinally viewed sciatic nerve (SN) before transecting the nerve (  C ) to enter the opposing extraneural compartment. Immediately before the transection, the needle tip was often seen to distend the opposing epineurium (  B ).