A summary of how to use ultrasound imaging of the spine to guide a paraspinous approach to spinal anesthesia, lumbar epidurals, or lumbar puncture. I recommend and practice the preprocedural ultrasoundassisted method in almost all cases. A realtime ultrasoundguided approach is theoretically feasible, but requires advanced skills and is highly challenging to perform when interlaminar spaces are small or hard to visualize.
The PPUSA method described works particularly well if the vertebral canal (anterior complexes) cannot be visualized.
If anterior complexes can be identified, a more refined and accurate method of marking is "Spinning on the AC" described here    • "Spinning on the AC"  US Imaging for...  

[This video is an extract from a longer video that also discusses the principles and rationale for the paraspinous (paramedian) approach to neuraxial blockade    • Paraspinous (Paramedian) Approach to ...  ]