Hip X-Ray "Frog Leg"

Pelvis Frog-leg lateral STD
Objective

Femoral head and neck.

Positioning

Patient supine.
Limb flexed, abducted and externally rotated.
Sole of the foot against the contralateral knee.
Central ray: perpendicular to the IR.

Centering

Hip joint

DR Parameters

75–85 kV · 20–30 mAs
SID ~100–115 cm · grid if indicated

CR Parameters

75–85 kV · 30–50 mAs · SID ~100–115 cm

Quality criteria

Femoral head and neck visible.
No excessive rotation.

Common errors

Incorrect limb position.
Incorrect centring.
Movement.

Practical notes

Check for metallic objects.
CONTRAINDICATED in suspected SCFE (Slipped Capital Femoral Epiphysis): forced abduction and external rotation may worsen acute epiphyseal slippage. → Perform the Löwenstein (cross-table lateral) view instead without mobilising the limb.
Routine gonadal shielding is no longer recommended (AAPM 2021); apply dose optimisation according to the local protocol.