Basilar skull fractures, breaks in bones at the base of the skull, require more force to cause than cranial vault fractures. Thus they are rare, occurring as the only fracture in only 4% of severe head injury patients. Caused by a blow to the back of the head, basilar fractures have characteristic signs: blood in the sinuses; a clear fluid called cerebrospinal fluid (CSF) leaking from the nose or ears; raccoon eyes (bruising of the orbits of the eyes that result from blood collecting there as it leaks from the fracture site); and battle sign (caused when blood collects behind the ears and causes bruising). Patients with basilar skull fractures are especially likely to get meningitis. Bones may be broken around the foramen magnum, the hole in the base of the skull through which the spinal cord enters and becomes the brain stem, creating the risk that blood vessels and nerves exiting the hole may be damaged.

Basilar skull fractures, breaks in bones at the base of the skull, require more force to cause than cranial vault fractures. Thus they are rare, occurring as the only fracture in only 4% of severe head injury patients (Graham and Gennareli, 2000; Orlando Regional Healthcare, 2004). Caused by a blow to the back of the head, basilar fractures have characteristic signs: blood in the sinuses; a clear fluid called cerebrospinal fluid (CSF) leaking from the nose or ears; raccoon eyes (bruising of the orbits of the eyes that result from blood collecting there as it leaks from the fracture site); and battle sign (caused when blood collects behind the ears and causes bruising). Patients with basilar skull fractures are especially likely to get meningitis (Downie, 2001). Bones may be broken around the foramen magnum, the hole in the base of the skull through which the spinal cord enters and becomes the brain stem, creating the risk that blood vessels and nerves exiting the hole may be damaged.