LATERAL WEIGHT-BEARING PROJECTION: FOOT

Lateral

Lateral weight bearing foot

• Have patient stand erect, with weight evenly distributed.
• Have patient stand on wood blocks placed on a step stool or the foot rest attached to the table, You also may use a special  wooden box with a slot for the cassette. (It has to be high enough form the floor to get the xray tube down into a horizontal beam position.)
• Provide some support for patient to hold onto for security.
• support vertical cassette between feet, with long axis of foot aligned to long axis of IR.
• Changed cassettes and turn patient for lateral of other foot for comparison after first lateral has been taken.

Cenral Ray:

• Direct CR horizontally to level of base of third metatasals.
• Minimum SID of 40 inches (100cm)

Collimation:

• Collimate to margins of feet (foot).

Radiographic Criteria on Lateral Foot Weight Bearing:

Structure Shown for Lateral Foot Weight Bearing

• The entire foot should be demonstrated, along with a minimum of 1 inch or 2 cm of distal tibia-fibula.
• Distal fibula should be seen superimposed over posterior half of the tibia, and plantar surfaces of heads of metatarsals should appear directly superimposed if no rotation is present.

Collomation and Central Ray:

• Center of collimated field (CR) should be to level of base of third metatarsal.
• Four sided collimation should include all surrounding soft tissue from the phalanges to the calcaneus and from the dorsum to the plantar surface of the foot with approximately 1 inch or 2 cm of the distal tibia fibula demonstrated.

Exposure Criteria of Lateral Foot Weight Bearing:

• Optimal density and contrast should visualize soft tissue and bony borders of superimposed tarsals and metatarsals.
• Adequate penetration of x-ray in the midfoot region.
• Bone trabecular marking should be sharp.