A skull fracture is a break in one or more of the eight bones that form the cranial portion of the skull, usually occurring as a result of blunt force trauma. If the force of the impact is excessive, the bone may fracture at or near the site of the impact and cause damage to the underlying structures within the skull such as the membranes, blood vessels, and brain. While an uncomplicated skull fracture can occur without associated  physical or neurological damage and is in itself usually not clinically significant, a fracture in healthy bone indicates that a substantial amount of force has been applied and increases the possibility of associated injury. Any significant blow to the head results in a concussion, with or without loss of consciousness. A fracture in conjunction with an overlying laceration that tears the epidermis and the meninges, or runs through the paranasal sinuses and the middle ear structures, bringing the outside environment into contact with the cranial cavity is called a compound fracture. Compound fractures can either be clean or contaminated. There are four major types of skull fractures: linear, depressed, diastatic, and basilar. Linear fractures are the most common, and usually require no intervention for the fracture itself. Depressed fractures are usually comminuted, with broken portions of bone displaced inward—and may require surgical intervention to repair underlying tissue damage. Diastatic fractures widen the sutures of the skull and usually affect children under three. Basilar fractures are in the bones at the base of the skull.
Basilar fractures have characteristic signs: blood in the sinuses; cerebrospinal fluid rhinorrhea (CSF leaking from the nose) or from the ears (cerebrospinal fluid otorrhea); periorbital ecchymosis  often called raccoon eyes (bruising of the orbits of the eyes that result from blood collecting there as it leaks from the fracture site); and retroauricular ecchymosis known as "Battles sign" (bruising over the mastoid process). Growing fracture
A growing skull fracture (GSF) also known as a craniocerebral erosion or leptomeningeal cyst due to the usual development of a cystic mass filled with cerebrospinal fluid is a rare complication of head injury usually associated with linear skull fractures of the parietal bone in children under 3. It has been reported in older children in atypical regions of the skull such as the basioccipital and the base of the skull base and in association with other types of skull fractures. It is characterized by a diastatic enlargement of the fracture.Various factors are associated with the development of a GSF. The primary causative factor is a tear in the dura mater. The skull fracture enlarges due, in part, to the rapid physiologic growth of the brain that occurs in young children, and brain cerebrospinal fluid (CSF) pulsations in the underlying leptomeningeal cystic mass. Cranial burst fracture
A cranial burst skull fracture, usually occurring with severe injuries in infants less than 1 year of age, is a closed, diastatic skull fracture with cerebral extrusion beyond the outer table of the skull under the intact scalp.Acute scalp swelling is associated with this type of fracture.