skull fractures

Epidurales

Hämatom bei Schädelfraktur bei einem Säugling.

Wachsende

Schädelfraktur: Die Fraktur der Kalotte war primär nur schmal, fissural (linkes Bild, frische Fraktur, Alter 6 Monate). Im Verlauf weitet sich der Frakturspalt deutlich (rechtes Bild, Alter 14 Monate). Pathogenetisch geht man von einer Mitverletzung der Dura mit Verlagerung von Anteilen derselben in den Frakturspalt aus. Dadurch wird die ossäre Überbauung verhindert und durch den positiven Druck von innen der Spalt eben sogar erweitert. Es besteht in der Folge die Gefahr einer Meningozele oder Enzephalozele.

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Fracture of

sinus frontalis in axial computertomography. Dorsal wall not affected.

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CT- Aufnahme

einer Schußverletzung

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Our DDX For

This Week IsLateral radiograph of the skull shows bilateral linear parietal lucencies coursing across the skull.The diagnosis was bilateral linear skull fractures in a child abuse patient.

pediatricimaging.org • CC-by-nc-sa 4.0

Preschooler

hit in the head with a golf clubAxial CT without contrast of the brain shows depression of the skull in the left temperoparietal region with an associated subgaleal hematoma containing subcutaneous air.The diagnosis was a depressed skull fracture.

pediatricimaging.org • CC-by-nc-sa 4.0

Infant who

fell 3 feet out of bed onto a wooden floor3D reconstruction from CT without contrast of the brain (left) shows a linear straight lucency that connects to the left lambdoid suture. Coronal CT (right) shows the same linear lucency lying under a large subgaleal hematoma.The diagnosis was a linear skull fracture and not an accessory suture of the skull based on the soft tissue swelling associated with the linear lucency.

pediatricimaging.org • CC-by-nc-sa 4.0

Toddler who

is unresponsiveAxial CT without contrast of the brain shows high density material in the subgaleal tissues posteriorly, a wide lucency in the right posterior skull along with two areas of depressed lucency in the left frontal skull, a rounded high-density lesion in the midline of the cerebellum, and decreased density of the cerebrum when compared to the normal density of the cerebellum along with loss of the normal gray matter-white matter differentiation.The diagnosis was a posterior subgaleal hematoma, a right posterior diastatic skull fracture and a left frontal depressed skull fracture, cerebellar contusion and diffuse cerebral edema in a child abuse patient.

pediatricimaging.org • CC-by-nc-sa 4.0

Radiopaedia • CC-by-nc-sa 3.0 • de

Skull fractures are common in the setting of both closed traumatic brain injury and penetrating brain injury. Their importance is both as a marker of the severity of trauma and because they are, depending on location, associated with a variety of soft tissue injuries.

This article will focus on a general terminology of fractures and delegate discussion of particular fracture patterns to separate articles (e.g. base of skull fractures). Facial fractures are also discussed separately.

Terminology

Skull fractures can be broadly divided in a variety of way:

anatomically
- base of skull
- skull vault
associated with overlying wound
- open (compound)
- closed
degree of displacement
- undisplaced
- depressed (5-10 mm)
number of fracture lines/fragments
- linear
- comminuted

Pathology

Fractures of the skull, as with fractures of any bone, occur when biomechanical stresses exceed the bone's tolerance. The pattern of fracturing depends on the location, direction and kinetic properties of the impact as well as intrinsic features of the skull .

Radiographic features

Plain radiograph

Plain radiographs have a limited role and are superseded by CT scans. They are no longer recommended to assess head injuries unless as part of a skeletal survey for a suspected non-accidental injury of a child .

CT

Skull fractures are best imaged with CT of the brain. Not only is CT sensitive to the detection fractures but it is also able to exquisitely characterize their extent and allow for surgical planning. Furthermore, it is obtained at the same time as the brain is imaged.

CT of the skull should be obtained volumetrically with small (<1 mm) voxels and be able to be reconstructed in multiple planes. It is essential that a bone algorithm is used if undisplaced fractures are to be visualized.

Fractures will appear as discontinuities in the bone and may or may not be displaced. They need to be distinguished from normal sutures, which have corticated margins that fractures lack. Almost invariably, if the fracture involves a paranasal sinus, middle ear or mastoid air cells, then they will contain some blood, which is a helpful clue to the presence of an underlying fracture.

When a fracture is identified, a careful search for adjacent soft tissue injury should be undertaken. Examples of soft tissue injuries include:

vascular
- arterial dissection, occlusion or rupture
  - arterial extradural hemorrhage
- arteriovenous fistula (e.g. direct caroticocavernous fistula)
- dural venous sinus injury
  - venous extradural hemorrhage
  - dural venous sinus thrombosis
extension through cranial nerve foramina or canals with neural damage
underlying cerebral hemorrhagic contusions
dural tears leading to CSF leak and intracranial hypotension

MRI

MRI is insensitive to fractures and it is often frightening how difficult it is to visualize fractures even when they are prominent and already known about on CT.

Treatment and prognosis

Skull fractures, if closed and undisplaced, rarely need any direct management, with treatment being aimed at any associated injury (e.g. extradural hematoma). In contrast, depressed fractures will often require surgical intervention for cosmesis and reduction in the incidence of post-traumatic epilepsy . Open (compound) fracture will usually require debridement to reduce the risk of subsequent infection .