RESUMEN
BACKGROUND: Navigation and robotics are important tools in the spine surgeon's armamentarium and use of these tools requires placement of a reference frame. The posterior superior iliac spine (PSIS) is a commonly used site for reference frame placement, due to its location away from the surgical corridor and its ability to provide solid fixation. Placement of a reference frame requires not only familiarity with proper technique, but also command of the relevant anatomy. OBSERVATIONS: Cadaveric analysis demonstrates a significant difference in PSIS location in males versus females, and additionally provides average thickness for accurate placement. LESSONS: In this technical note, the authors describe the precise technique for PSIS frame placement in addition to relevant anatomy and offer solutions to commonly encountered problems.