LATERAL PROJECTIONS : ANKLE XRAY

Mediolateral and Alternate Lateromedial Projection

Xray examination of ankle normally is taken mediolateral as some departments rules. An alternate lateromedial projection can also be taken but it more uncomfortable for the patient specially on broken ankle or when patient is a child. This projection is useful in the evaluation of fractures (broken ankles), sprains, dislocations, and joint effusions associated with other joint pathologies.

Technical Factors:

Mediolateral Lateral

IR size - 24 x 30 cm (10 x 12 inches)
Divide in half crosswise
Detail screen
Digital IR - use lead masking
60 +- 5 kV range
mAs 5

Shielding:

Place lead shield over pelvic area.

Patient Position:

Place patient in the lateral recumbent position, affected side down; give pillow for head; flex of affected limb about 45 degree; place opposite leg behind the injured limb to prevent overrotation.

Latera-Mediolateral Ankle

Part Position (Mediolateral Projection)
Center and align ankle joint to CR and to long axis of portion of IR being exposed.
Place support under knee as needed to place leg and foot in a true lateral position.
Dorsiflex foot so plantar surface is at right angle to leg or as far as patient can tolerate; do not force. (This will help maintain a true lateral position.)

Central Ray:

CR perpendicular to IR, directed to medial malleolus
Minimum SID of 40 inches (100 cm)

Lateral View Ankle

Collimation:

Collimation to include distal tibia and fibula to midmetatasal area.

CR or DR:

Close collimation and lead masking are important over unused portions of image plate.

Alternate Lateromedial Projection:

This lateral may be taken rather than the more commonly preferred mediolateral projection. (This position is more uncomfortable for the patient but may make it easier to achieve a true lateral position.)

Radiographic Criteria: Lateral Ankle

Structure Shown:

The distal one-third of the tibia and fibula with the distal fibula superimposed by the distal tibia, the talus, and calcaneus will appear in lateral profile.
The tuberosity of the fifth metatasals, the navicular, and cuboid also will be visualized.

Position:

No rotation is evidenced by the distal fibula being superimposed over the posterior half of the tibia. The tibiotalar joint will be open with uniform joint space.

Collimation and CR:

The center of the four-sided collimation (CR) should be to the mid-ankle joint. The collimation field should include the distal one-third of the lower leg, the calcaneus, the tuberosity of the fifth metatasal, and surrounding soft tissue structures.

Exposure Criteria:

No motion, as evidenced by sharp bony margins and trabecular patterns. The lateral malleolus should be seen through the distal tibia and talus, and soft tissue must be demonstrated for evaluation of joint effussion.