Foot (lateral view)

The lateral foot projection is part of the three view series examining the phalanges, metatarsals and tarsal bones that make up the foot. This view additionally examines the talocrural joint.

Indications

This view is useful in the assessment for joint abnormalities, determining the degree of dorsal or plantar displacement in fractured bones, soft tissue effusions or gas (i.e. osteomyelitis) and in locating opaque foreign bodies.

Patient position

• the patient may be supine or upright depending on comfort 
• the affected leg is externally rotated until the distal limb is parallel to the table, in many cases, the patient will have to half roll onto the affected side
• the lateral aspect of the foot will be in contact with the image receptor 
• the non-affected side is kept posterior to prevent over rotation 
• the foot is in slight dorsiflexion 
• the planter surface should be perpendicular to the image receptor 

Technical factors 

• mediolateral projection
• centring point
  • base of metatarsals or midfoot 
• collimation
  • anteriorly to skin margin of the distal phalanges
  • posteriorly to skin margin of the calcaneus
  • superior to the talocrural joint
• orientation
  • landscape
• detector size
  • 18 cm x 24 cm
• exposure
  • 55-60 kVp
  • 4-6 mAs
• SID
  • 100 cm
• grid
  • no

Image technical evaluation

• the metatarsals are almost completely superimposed with only the tuberosity of the 5^th metatarsal seen in profile 
• the domes of the superior aspect of the talus are superimposed 
• tibiotalar joint is open

Practical points

If the patient has a larger distal limb it may be difficult to position it parallel to the image receptor, in these cases a foam block can be used to raise the height of the foot to maintain an optimal position. 

Anterior-posterior malalignment of the talar domes is due to over or under rotation of the foot. To adjust this, check the heel is not raised too far or alternately the toes if the patient cannot correct this position it can be aided with a small wedge sponge.