A skull fracture refers to structural alterations in the normal architecture of the skull caused by external trauma. Approximately 15% to 20% of closed craniocerebral injuries involve skull fractures. The significance of a skull fracture often lies not in the fracture itself but in concurrent injuries to the dura mater, brain tissue, intracranial blood vessels, or cranial nerves.
Mechanism of Injury
The occurrence of a skull fracture following external force depends on factors such as the magnitude, direction, and nature of the force, the contact area between the object and the skull, and the anatomical characteristics of the affected cranial region. Upon impact, the skull undergoes bending deformation. If the external force dissipates, the skull typically returns to its original shape. However, when the deformation exceeds the elastic limits of the cranial bone, a fracture results.
Classification
Classification by morphology:
- Linear fracture
- Depressed fracture
- Comminuted fracture (often accompanied by depression)
- Penetrating fracture (commonly associated with projectile injuries)
Classification by location:
- Calvarium (skull vault) fracture
- Skull base fracture
Classification by communication with external environment:
- Closed fracture
- Open fracture
Skull base fractures, although not directly exposing intracranial structures, are classified as open fractures if accompanied by dura mater tears leading to cerebrospinal fluid leakage or intracranial pneumocephalus.
To be continued