Acute CT Brain
Scalp and skull injury

Key points

  • Assess the brain and bone windows on every brain CT
  • Skull sutures are jagged
  • Acute skull fractures are straight and are not corticated

Assessment of every brain CT requires systematic viewing of both the bone windows and the brain windows.

The bone windows should be given particular attention in the context of head injury to look for a fracture. The brain windows are used to look for intracranial haemorrhage.

Both bone and brain window images provide detail of scalp injury, also visible clinically.

Scalp haematoma and skull fracture - CT brain

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Scalp haematoma and skull fracture - CT brain

  • The bone window images show a clearly defined skull fracture
  • The brain window image shows a small intracranial collection of blood in the subarachnoid space
  • A small scalp haematoma is seen on both the bone and the brain window images

Fracture or suture?

In the context of head injury, a knowledge of the appearance of normal sutures is essential to avoid misinterpretation.

The sutures are found in typical anatomical locations and are characteristically jagged in appearance. Sutures have corticated edges whereas the edge of fractured skull bones are not corticated.

Skull fracture v suture - CT brain

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Skull fracture v suture

  • Only one of these is a fracture - but which one?
  • The suture is in the typical position of the lambdoid suture and it appears jagged and corticated
  • The fracture passes across both inner and outer table of the skull in a straight line

Skull fracture v suture - CT brain

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Skull fracture v suture

  • At the interface of a suture the surface of each bone is covered by a layer of cortical bone which is continuous with inner and outer tables of the skull
  • At the site of a skull fracture the bones are not corticated
  • Note how straight the fracture is compared to the jagged suture

Depressed skull fracture - CT brain

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Depressed skull fracture

  • Severe trauma to the skull may result in depression of the skull bones
  • The bone window images provide good detail of the depressed skull fracture
  • The brain windows show the accompanying intracranial haematoma

Basal skull fracture - CT brain

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Basal skull fracture

  • Fractures of the basal skull can be difficult to identify
  • In the setting of acute head injury, a fluid level (blood) in the sphenoid sinus can be a helpful sign of a basal skull fracture