Anatomical Evaluation of the Sacral Hiatus Using Ultrasound Imaging: Factors That Inhibit Needle Insertion During Caudal Epidural Block Procedures.

The mean distance from the skin to the sacral cornua and BMI were found to be associated with the palpability of the sacral hiatus, and sacral base protrusion was demonstrated to be associated with the difficulty of needle insertion into the sacral hiatus.