Isolated skull fractures are not very serious injuries, but usually the presence of a skull fracture indicates that significant enough impact occurred to cause brain trauma, which is quite serious.

Skull fractures can cause significant harm: Broken fragments of skull can lacerate or bruise the brain or damage blood vessels. If the fracture occurs over a major blood vessel, significant bleeding can occur within the skull, so head injury patients with skull fracture have many more intracranial hematomas than those without fractures.