It is important to visualize the inferior gluteal artery medially next to the sacral margin. It indicates the correct level of needle insertion and it is a safeguard that allows you to avoid piercing the artery during needle insertion.
Sacral plexus (red arrow), inferior gluteal artery (red shadow), iliac bone (magenta asterix), sacral bone (green asterix), piriformis (white asterix), L = lateral, M = medial.
