Sonological Correlation of the Caudal Block Triangle with Surface Anatomy in Children Under Two Years: A Cross-sectional Study

Abstract Background: Caudal epidural block is commonly used for infraumbilical surgeries in children, with the sacral hiatus traditionally identified using surface landmarks of the posterior superior iliac spines and sacral cornua. Ultrasound enables verification of this technique, though data in the Indian pediatric population are limited. This prospective cross-sectional study evaluated the correlation between landmark-based and ultrasound identification of the sacral hiatus. Methodology: During the study period, 159 American Society of Anesthesiologists I–II children under 2 years of age undergoing elective anorectal or urogenital surgery were included in this study. After induction of general anesthesia, the caudal block triangle was identified with the landmark technique, followed by ultrasound-guided localization of the sacral hiatus. The triangle’s sides were measured in the left lateral position.