Authors of section


Florian Gebhard, Phil Kregor, Chris Oliver

Executive Editor

Chris Colton

Open all credits

Supine position knee flexed 30°

1. General considerations

The supine position with the knee flexed 30° provides good support for the knee and relaxes the tendency of the gastrocnemius muscle to pull the condyles into hyperextension. It has the disadvantage that, for lateral image intensifier use, the limb may need to be lifted up.

2. Positioning

Position the patient supine on a radiolucent table with the knee in 30° flexion. The knee is supported by a cushion, or rolled sheets.

It is useful to have a small sandbag just behind the same buttock to prevent external rotation of the limb.

supine position knee flexed 30

3. Carbon triangle

Alternatively, a carbon triangle may be used.

supine position knee flexed 30