Knee - AP Bilateral Weightbearing

Radiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Knee - AP Bilateral Weightbearing
Area Covered	Distal femur, proximal tibia and fibula, bilateral tibiofemoral joint spaces under the effects of gravity
Pathology shown	Joint space narrowing due to cartilage degeneration or other knee joint pathologies
Radiographic Anatomy	Knee Radiographic Anatomy
IR Size & Orientation	35 x 43cm Landscape
Film / Screen Combination	Regular (CR and DR as recommended by manufacturer)
Bucky / Grid	Moving or stationary grid
Filter	No
Exposure	66 kVp 12 mAs
FFD / SID	100cm
Central Ray	CR perpendicular to IR or 5° to 10° caudad on thin patients Directed to a midpoint between the knee joints 1.2cm below the apex of the patella
Collimation	Collimate to bilateral knee joint region Include distal femur and proximal tibia / fibula to see alignment of joints
Markers	Distal and Lateral Marker orientation AP
Shielding	Gonadal (check your department's policy guidelines)
Respiration	Not applicable
Positioning	Patient erect, standing on a step to place patient high enough for horizontal ray (Some X-ray tubes dont go all the way down to the ground, to counter this you raise the patient on a step) Patient their back against the upright bucky Position feet straight ahead with weight evenly distributed on both feet (support handles may be required for some patients) Align and centre bilateral legs and knees to IR CR perpendicular to IR or 5° to 10° caudad on thin patients, directed to a midpoint between the knee joints,1.2cm below the apex of the patella
Critique PACEMAN	Positioning Area Covered Collimation Exposure
Special Notes