Basilar skull fracture

Basilar skull fracture
A subtle temporal bone fracture as seen on CT in a person with a severe head injury
Classification and external resources
Specialty	emergency medicine
ICD-10	S02.1
ICD-9-CM	801.1
eMedicine	med/2894
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A basilar skull fracture (or basal skull fracture) is a fracture of the base of the skull, typically involving the temporal bone, occipital bone, sphenoid bone, and/or ethmoid bone.

This type of fracture is rare, occurring as the only fracture in just 4% of severe head injury patients.

Such fractures can cause tears in the membranes surrounding the brain, or meninges, with resultant leakage of the cerebrospinal fluid (CSF). The leaking fluid may accumulate in the middle ear space, and dribble out through a perforated eardrum (CSF otorrhea) or into the nasopharynx via the eustachian tube, causing a salty taste. CSF may also drip from the nose (CSF rhinorrhea) in fractures of the anterior skull base, yielding a halo sign. These signs are characteristic for basilar skull fractures.

Basilar skull fractures include breaks in the posterior skull base or anterior skull base. The former involve the occipital bone, temporal bone, and portions of the sphenoid bone; the latter, superior portions of the sphenoid and ethmoid bones. The temporal bone fracture is encountered in 75% of all basilar skull fractures and may be longitudinal, transverse or mixed, depending on the course of the fracture line in relation to the longitudinal axis of the pyramid.

Bones may be broken around the foramen magnum, the hole in the base of the skull through which the spinal cord exits and becomes the brain stem, creating the risk that blood vessels and nerves exiting the hole may be damaged.

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