Trauma X-ray - Axial skeleton
Skull

Key points

  • Skull X-ray is not indicated for identification of skull fractures
  • CT is usually required if there is history of sufficient trauma to cause a fracture
  • Specific X-ray views are required to look for foreign bodies in the scalp

Bones and fractures

X-rays are rarely indicated for detection of skull fractures. If there is a history of sufficient force to result in suspected fracture then CT is usually required. CT is necessary to look for underlying intracranial haemorrhage.

This page discusses normal skull anatomy as seen on X-ray, and the occasional indications for post traumatic views of the skull.

Normal skull - Lateral

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Normal skull - Lateral

  • Anatomically the skull has inner and outer surfaces or 'tables'
  • Skull X-rays show the course of vessels which indent the inner table
  • These vascular indentations branch and taper - whereas fractures do not usually branch or taper

Normal skull - AP

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Normal skull - AP

  • Sutures have a saw-tooth appearance which distinguishes them from fractures which form smooth lines

Skull fractures - AP

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Skull fractures - AP

  • The black lines represent skull fractures
  • These lines are too smooth to be sutures and do not branch like the vascular markings of the skull

Basal skull fractures

Fractures of the skull base are not readily visible on plain X-rays. If injury to the skull base is suspected clinically then CT is usually indicated.

Blood or cerebrospinal fluid (CSF) may leak into the para-nasal sinuses following basal skull fracture. In the context of trauma an air/fluid level seen in the sphenoid sinus is radiographic evidence of basal skull fracture.

Sphenoid air-fluid level

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Sphenoid air-fluid level

  • No fracture is visible
  • The air-fluid level seen in the sphenoid sinus is due to haemorrhage or CSF leakage due to basal skull fracture
  • The other paranasal sinuses also contain blood due to facial bone injury

Skull - Depressed fracture

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Skull - Depressed fracture

  • Displaced or depressed skull fractures may result in overlapping bone which causes white lines of increased density
  • Note: The sphenoid sinus is clear - however this does not exclude a basal skull fracture

Scalp foreign body X-ray

To look for foreign bodies in the scalp specific radiographic settings are required and the X-ray beam is aimed tangential to the area of injury. It is therefore essential to specify that 'foreign body X-rays' are required.

Material that is not very dense, such as wood, will not show up on X-ray. Good quality X-rays will show denser material such as glass.

Scalp foreign bodies

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Scalp foreign bodies

  • A dedicated soft tissue X-ray taken at an appropriate angle clearly shows several foreign body fragments in the scalp - glass in this case