Patient Positioning:
The patient is placed in a prone position with the heels rotated laterally and a cushion pillow is used as an iliac wedge to facilitate the exposure of the skin surface in the coccygeal area.
Probe Positioning:
Use a transverse image for the sacral hiatus and dorsal sacrococcygeal ligament between the bilateral sacral cornua first, then rotate the probe by 90 ° to show the longitudinal view of the sacral hiatus and coccyx.
Note: patient with acute local pain after epidural sacral injections with steroids. Epidural lipomatosis refers to an accumulation of fat within the spinal epidural space which can lead to compression of the thecal sac. The ultrasound with bulging of the sacrococcygeal ligament – covering the hiatus – was confirmed by MRI.