Mandible x-rays

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An orthopantomogram (OPG) is a good view to demonstrate most mandibular fractures.

 

A PA mandible shows the displacement of fractures. It also demonstrates symphysis menti fractures which can be missed on the OPG.

pa-anatomy

Image from WikiRadiography

If an OPG cannot be obtained, a lateral view can be helpful. The body and ramus can be viewed along with the TMJ articulation.

lateral-anatomy

Image from WikiRadiography

 

Know your anatomy

mandible-anatomy

Image from WikiRadiography

 

 

Follow the line of the mandible.

  • Remember that the air-filled oesophagus often means that black lines cross the mandible near the angle of the mandible (see image above).

 

Look at the condylar and coronoid process, rami and body, submental symphysis, and alveolar ridge for fractures

  • Condylar process fractures can occur at the base so look carefully as they are easily missed.
  • In general, if you see one mandibular fracture then look for another one as it is common to have more than one, or TMJ dislocation.

 

A Guardsman’s fracture is where there is a fracture of the symphysis and both condyles. This is due to a fall with impact on the midpoint of the chin.


Management

  • Favourable fractures are held in alignment.
  • Unfavourable fracture are displaced by the muscles pulling them.
  • Mandibular fractures of the body or angle of the mandible can be managed conservatively, unless they are displaced, in which case reduction and internal fixation may be required.
  • Condylar fractures are usually managed conservatively, unless there is occlusion of normal movement due to dislocation of the condylar head.

If you want to test yourself then Norwich Image Interpretation Course has a great online facial x-ray quiz.

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About 

Tessa Davis is a paediatric emergency registrar from Glasgow and Sydney, but currently living in London. Tessa tries to spend time with her 3 kids in between shifts. @tessardavis | + Tessa Davis | Tessa's DFTB posts