Calcaneus (lateral view)

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The calcaneus lateral view is part of the two view calcaneus series; this projection is used to assess the calcaneus, talocrural, talonavicular and talocalcaneal joint.

As technology advances, computed tomography (CT) has widely been used  to better visualize and characterize calcaneum fragment displacements and fracture lines. Yet, there remain many institutions (especially in rural areas) where CT is not readily available.

Indications

This view is able to assess for bony lesions and also helps in determining the extent and alignment of fractures (i.e. Böhler and Gissane angle).

Patient position

  • the patient is in a lateral recumbent position on the table
  • the lateral aspect of the knee and ankle joint should be in contact with the table resulting in the tibia lying parallel to the table
  • the leg can be bent or straight 
  • foot in dorsiflexion 
  • place the opposite leg behind the injured limb to help avoid over-rotation

Technical factors

  • mediolateral projection
  • centering point
    • 2.5 cm inferior to the prominence of the medial malleolus of the distal tibia
  • collimation
    • anteriorly from the hindfoot to the extent of the skin margins of the most posterior portion of the calcaneus
    • superior to examine talocrural joint
    • inferior to the skin margins of the plantar aspect of the foot
  • orientation  
    • landscape
  • detector size
    • 18 cm x 24 cm
  • exposure
    • 50-60 kVp
    • 3-5 mAs
  • SID
    • 100 cm
  • grid
    • no

Image technical evaluation 

The calcaneus is in profile with the talonavicular joint open; the distal fibula is superimposed by the posterior portion of the distal tibia, the tarsal sinus should appear open.

The talar domes are superimposed allowing for adequate inspection of the superior articular surface of the talus.

The joint space between the distal tibia and the talus is open and uniform.

Practical points

Superior-inferior malalignment of the superior aspect of the talus is resultant of the tibia not lying parallel to the image receptor. To adjust this, either lower the knee to better match the ankle or place the ankle on a small sponge to better match the knee.

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. 

In trauma, it may not be possible to position the patient as above, in these cases the same principles can be applied with a modified horizontal beam view. The patient can remain supine with an image receptor placed vertically adjacent to the lateral aspect of the upright foot; the X-ray beam is directed horizontally, centered 2.5 cm inferior to the prominence of the medial malleolus of the distal tibia.