Knee X-Ray AP
Objective
Femoral condyles and tibial plateau.
Positioning
Patient supine with knee as extended as possible (0–5° of flexion to open the joint line).
Leg in neutral position, patella facing anteriorly.
Central ray: perpendicular to the IR.
Correct alignment.
Centering
Joint line
DR Parameters
65–75 kV · 8–12 mAs
SID ~100–115 cm · grid if indicated
CR Parameters
65–75 kV · 12–20 mAs · SID ~100–115 cm
Quality criteria
Femoral condyles and tibial plateau visible.
Joint line open.
No rotation.
Common errors
Knee rotation.
Incorrect centring.
Movement.
Practical notes
Check for metallic objects.
Always mark the examined side (R/L) before exposure.