CT Brain Anatomy
Skull bones and sutures

Key points

  • Main skull bones - frontal, parietal, occipital, ethmoid, sphenoid and squamous temporal
  • Main sutures - coronal, sagittal, lambdoid and squamosal
  • Injury to the pterion area may lead to formation of extradural haematoma due to injury of the middle meningeal artery

The brain is located inside the cranial vault, a space formed by bones of the skull and skull base. Everything inside the cranial vault is 'intra-cranial' and everything outside is 'extra-cranial'.

Skull bones

Bones of the skull and skull base - frontal, parietal, occipital, ethmoid, sphenoid and temporal bones - all ossify separately and gradually become united at the skull sutures.

The skull has inner and outer tables of cortical bone with central cancellous bone called 'diploe'.

Skull bone structure - CT brain - (bone windows)

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 bone structure - CT brain - (bone windows)

  • Note the appearance of the skull sutures which are jagged - not to be confused with fractures which are typically straight

Bone windows

  • Bones of the skull are assessed viewing the 'bone window' CT images
  • Note that no detail of brain structure is provided on these window settings

Sutures

The main sutures of the skull are the coronal, sagittal, lambdoid and squamosal sutures. The metopic suture (or frontal suture) is variably present in adults.

Coronal suture - unites the frontal bone with the parietal bones

Sagittal suture - unites the 2 parietal bones in the midline

Lambdoid suture - unites the parietal bones with the occipital bone

Squamosal suture - unites the squamous portion of the temporal bone with the parietal bones

Metopic suture - (if present) unites the 2 fontal bones

Skull bones and sutures - (lateral view)

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 bones and sutures - (lateral view)

  • Coronal suture (BLUE)
  • Lambdoid suture (GREEN)
  • Squamosal suture (RED)
  • Other sutures (BLACK DOTTED)

Pterion

  • The frontal, parietal, temporal and sphenoid bones unite at the 'pterion' - the thinnest part of the skull
  • The middle meningeal artery runs in a groove on the inner table of the skull in this area

Pterion - clinical significance

  • Fractures to the pterion area can be complicated by injury to the middle meningeal artery and formation of an extradural haematoma

Skull bones and sutures - (superior view)

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 bones and sutures - (superior view)

  • Coronal suture (BLUE)
  • Lambdoid suture (GREEN)
  • Squamosal suture (RED)
  • Sagittal suture (PURPLE)
  • Metopic suture (ORANGE) - variably present in adults

Cranial fossae

At the skull base the bones of the cranial vault form the cranial fossae which accommodate and support the brain.

Cranial fossae - CT brain - (bone windows)

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Cranial fossae - CT brain - (bone windows)

  • Anterior cranial fossa - accommodates the anterior part of the frontal lobes
  • Middle cranial fossae - accommodate the temporal lobes
  • Posterior cranial fossa - accommodates the cerebellum and brain stem
  • Pituitary fossa (PF) - accommodates the pituitary gland