LAUSR

561 Saudi Journal of Anesthesia / Volume 14 / Issue 4 / October‐December 2020 ligament, the body of sacrum, caudal space could be seen we saw the thick hyperechoic line, which was starting from coccyx towards the sacral area, same structure was seen in the midline, when the probe was moved left/right, the structure disappeared. This structure could be a fibro‐fatty structure, suggesting the presence of a fibrous band/septum. The unilateral block is rare with caudal anesthesia. Causes of unilateral caudal anesthesia can be misdirected needle or anatomical difficulties or congenital fibrous/connective tissue bands in the caudal epidural space. We emphasize the importance of ultrasound when performing caudal epidural injection to identify the anatomical details and avoiding complications and failed block.