出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/11 09:08:57」(JST)
| Basilar skull fracture | |
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| Classification and external resources | |
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A subtle temporal bone fracture as seen on CT in a person with a severe head injury
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| ICD-10 | S02.1 |
| ICD-9 | 801.1 |
| eMedicine | med/2894 |
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.[1][2]
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.[3]
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.[4]
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.[5]
Due to the proximity of the cranial nerves, injury to those nerves may occur.[3] This can cause palsy of the facial nerve or oculomotor nerve or hearing loss due to damage of cranial nerve VIII.[3]
Evidence does not support the use of prophylactic antibiotics regardless of the presence of a cerebral spinal fluid leak.[6]
Non-displaced fractures usually heal without intervention. Patients with basilar skull fractures are especially likely to get meningitis.[7] Unfortunately, the efficacy of prophylactic antibiotics in these cases is uncertain.[8]
Acute injury to the internal carotid artery (carotid dissection, occlusion, pseudoaneurysm formation) may be asymptomatic or result in life-threatening hemorrhage. They are almost exclusively observed when the carotid canal is fractured, although only a minority of carotid canal fractures result in vascular injury. Involvement of the petrous segment of the carotid canal is associated with a relatively high incidence of carotid injury.[9]
Basilar skull fractures are a common cause of death in many motor racing accidents. Drivers who have died as a result of basilar skull fracture include Formula One drivers Roland Ratzenberger and Ayrton Senna, Indianapolis 500 drivers Bill Vukovich, Tony Bettenhausen, Floyd Roberts, and Scott Brayton, NASCAR drivers Dale Earnhardt Sr., Adam Petty, Tony Roper, Kenny Irwin, Jr., Neil Bonnett, John Nemechek, J. D. McDuffie, and Richie Evans, CART drivers Jovy Marcelo, Greg Moore and Gonzalo Rodriguez, and ARCA drivers Blaise Alexander and Slick Johnson.
To prevent this injury, all major motor sports sanctioning bodies now mandate the use of head and neck restraints, such as the HANS device.
1. 2001 Daytona 500 and death of Dale Earnhardt
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| リンク元 | 「頭蓋底骨折」 |
| 関連記事 | 「basal」「fracture」「skull」 |