Spinopelvic parameters

• Pelvic tilt (PT) - angle b/w vertical reference line (femoral head) & midpoint of sacral end plate
• Sacral slope (SS) - angle b/w sacral end plate & horizontal reference line
• Pelvic incidence (PI) - angle b/w perpendicular line of the sacral end plate & center of femoral head

• PI = SS + PT
• PI תמיד קבוע
  • if ↑PT → ↓SS;
  • if ↓PT → ↑SS;