Injection inside the paraneural
sheath of the sciatic nerve: Direct comparison among ultrasound imaging, macroscopic anatomy, and histologic analysis.
Lin, "Ultrasound standard for popliteal sciatic block: Circular expansion of the paraneural
sheath with the needle in-plane fromlateral-to-medial in the 'reverse Sim's position'," British Journal of Anaesthesia, vol.
If needed, the skin incision and muscle dissection were extended to identify the most proximal spread of dye within the paraneural sheath.
In all cases, the SN and its branches were easily visualized with ultrasound and paraneural injection was achieved.
Interestingly, in the anatomic study, blue dye was observed to extend within the paraneural sheath to a much greater degree than that seen under ultrasound in the case series (mean 14.5 cm compared with 4.7 cm, resp.).
Finally the paraneural
fascia, the outermost connective layer that surrounds the whole fascicles within the epineurium, is hyperintense in the 3D SPGR fat suppressed images and hypointense in the TSE T1 weighted images.