Facial bone x-rays

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There are two views – occipito-mental view and occipito-mental 30o view

The occipito-mental view demonstrates the upper and middle thirds of the face including the orbital margins, frontal sinuses, zygomatic arches and maxillary antra

The occipito-mental 30o view shows 30o of caudal angulation. The orbits are seen less well, but zygomatic arches and the walls of the maxillary antra are seen clearly.

Look at the McGrigor lines on these two views:

Line 1:

Look for

  • Widening of the zygomatico-frontal sutures
  • Fractures of the superior rim of the orbits
  • ‘Black eyebrow’ sign due to orbital emphysema
  • Opacification/air-fluid level in the frontal sinuses

Line 2:

Look for

  • Fractures of the superior aspect of the zygomatic arch
  • Fractures of the inferior rim of the orbits
  • Soft tissue shadow in the superior maxillary antrum
  • Fractures of the nasoethmoid bones and medial orbits

Line 3:

Look for

  • Fractures of the inferior aspect of the zygomatic arch
  • Fractures of the lateral maxillary antrum
  • Opacification/air-fluid level in the maxillary sinuses
  • Fractures of the alveolar ridge

 


 

Common fractures and their management

Orbital fractures

Blowout fracture

  • A direct blow to the eye causes the intraocular pressure to rise
  • This causes a fracture to the orbital floor (the weakest part of the orbit)
  • Muscle/fat herniates down into the maxillary sinus
  • Results in a ‘teardrop’ of soft tissue in the roof of the maxillary sinus
  • Can be associated with tropia in upward gaze
  • Will require a facial bones CT (with reconstruction) and urgent maxillofacial referral

Image from RCEMLearning

Orbital emphysema

  • The medial wall of the orbit can also fracture
  • There can be movement of air from the ethmoid sinuses into the orbit
  • This causes the ‘black eyebrow’ sign

Case courtesy of Dr Brendon Friesen, Radiopaedia.org. From the case rID: 41399

Zygoma fractures

Image from Wikipedia

  • The zygoma is made up of three arms:
  • The orbital process leads up to the zygomatic-frontal suture
  • The zygomatic arch
  • The maxillary process
  • A fracture in one can be accompanied by fractures in the others (tripod fracture)

Zygomatic arch fracture

  • Always check the other arms to make sure this is not a tripod fracture
  • Does not usually require surgical intervention unless there is an issue with mouth opening
  • The temporalis muscle can become trapped in a depressed zygomatic arch fracture
zygomatic-arch

Image from RCEMLearning

Tripod fracture (zygomaticomaxillary complex fracture)

  • Look for widening of the zygomatic-frontal suture
  • Look at the arch itself
  • If there is an inferior orbital rim fracture, then look along to see if there is a maxillary sinus wall fracture
  • Can be associated with an air-fluid level in the maxillary sinus
  • Can be associated with trismus due to temporalis muscle impingement
  • Can be associated with infraorbital nerve damage – infraorbital numbness

Image from RCEMLearning

  • If there is any diplopia or reduced visual acuity then urgent maxillofacial surgery referral is required, otherwise this can be done as an outpatient
  • Advise the patient:
    • Not to blow their nose
    • Not to hold their nose closed when they sneeze
  • The reason for this advice is that it could cause surgical emphysema

Maxilla fractures

These are classified using the Le Fort classification system. Fracture of the pterygoid process is mandatory for a Le Fort fracture to be diagnosed.

Le Fort 1 (floating palate):

  • Horizontal maxillary fracture at the level of the nasal fossa
  • Leaves a ‘floating’ palette
  • Fractures are through the lateral and inferior walls of the maxillary sinus, and the alveolar ridge

 

Le Fort 2 (floating maxilla):

  • Pyramid shape
  • Base of pyramid is the alveolar ridge
  • Fractures pass through the lower nasal bridge, the inferior orbital rim, lateral wall of the maxillary sinus, and the lacrimal bones
lefort-ii

Image from LITFL

Le Fort 3 (floating face):

  • The entire facial skeleton is separated from the skull
  • Fractures go through the nasofrontal suture, the maxillo-frontal suture,  the orbital wall, and the zygomatic arch
  • The fracture line runs parallel to the base of the skull
lefortclassification

Image from LITFL

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