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.
Probe Positioning:
To identify the correct level, start with a saggital plane of the spinous processes. Then rotate the probe by 90 ° to show the spinous process and adjacent structures (lamina of the vertebral arch, facet joint,
accessory process, and mamillary process). The facet joints can be demonstrated in either longitudinal (sagittal) or transverse planes.
Note: osteophytes and sometimes effusion (if activated) can be detected by ultrasound in osteoarthritis of the facet joints.