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.
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.
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
