Foot (medial oblique view)

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The medial oblique projection is part of the three view series examining the phalanges, metatarsals and tarsal bones that make up the foot.

Indications

This view demonstrates the location and extent of fractures in the foot and joint space abnormalities. It is also used in the determination of osteomyelitis and examination of foreign bodies.

Patient position

  • the patient may be supine or upright depending on comfort
  • the affected leg must be flexed enough that the plantar aspect of the foot is resting on the image receptor
  • the foot is medially rotated until the plantar surface sits at a 45° angle to the image receptor

Technical factors 

  • AP oblique projection
  • centering point
    • x-ray beam centered to the base of the 3 metatarsal
    • the beam will be perpendicular to the image receptor 
  • collimation
    • lateral to the skin margins
    • anterior to the skin margins of the distal phalanges
    • posterior to the skin margins of the calcaneum
  • orientation  
    • portrait
  • detector size
    • 18 cm x 24 cm
  • exposure
    • 50-55 kVp
    • 3-4 mAs
  • SID
    • 100 cm
  • grid
    • no

Image technical evaluation

  • superimposition is evident at the bases of the of 1and 2metatarsals 
  • there is no superimposition of the 3 to 5 metatarsal
  • base of the 5th metatarsal is free of superimposition from any structure 
  • tarsal sinus is visible 
  • joint spaces around the cuboid are open and equal
  • cuboid is free of superimposition

Practical points

The metatarsal and tarsal bones are the most reliable rotation indicator.

If the foot is over rotated the base of the 5 metatarsal will be superimposed by the tubercle of the 4metatarsal.

If the foot is under rotated the bases of the 4 and 5 metatarsals will overlap; the image may have a closer resemblance to the DP projection.