Basilar skull fracture
Encyclopedia
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 pathognomonic
for basilar skull fracture.
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.
Due to the proximity of the cranial nerves, injury to those nerves may occur. This can cause palsy
of the facial nerve
or oculomotor nerve
or hearing loss due to damage of cranial nerve VIII.
s regardless of the presence of a cerebral spinal fluid leak.
. Unfortunately, the role of prophylactic antibiotics in these cases is unclear.
(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.
To prevent this injury, all major motor sports sanctioning bodies now mandate the use of head and neck restraints, such as the HANS device
.
Fracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
of the base of the skull, typically involving the temporal bone
Temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum.The temporal bone supports that part of the face known as the temple.-Parts:The temporal bone consists of four parts:* Squama temporalis...
, occipital bone
Occipital bone
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoidal in shape and curved on itself...
, sphenoid bone
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
, and/or ethmoid bone
Ethmoid bone
The ethmoid bone is a bone in the skull that separates the nasal cavity from the brain. As such, it is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction. The ethmoid bone is one of the bones that makes up the orbit of the eye...
.
This type of fracture
Bone fracture
A bone fracture is a medical condition in which there is a break in the continuity of the bone...
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
Meninges
The meninges is the system of membranes which envelopes the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.-Dura...
, with resultant leakage of the cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF). The leaking fluid may accumulate in the middle ear space, and dribble out through a perforated eardrum (CSF otorrhea) or into the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
via the eustachian tube
Eustachian tube
The Eustachian tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi...
, causing a salty taste. CSF may also drip from the nose (CSF rhinorrhea
Rhinorrhea
Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant amount of mucous fluid. The condition, commonly known as "runny nose", occurs relatively frequently and is not usually considered dangerous. Rhinorrhea is a common symptom of allergies or certain diseases,...
) in fractures of the anterior skull base, yielding a halo sign
Halo sign
In radiology, the halo sign is a finding on ultrasound that suggests the diagnosis of temporal arteritis. The standard diagnostic test for temporal arteritis is biopsy; however, ultrasound and MRI show promise for replacing it....
. These signs are pathognomonic
Pathognomonic
Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...
for basilar skull fracture.
Signs and symptoms
- Battle's signBattle's signIn medical terminology, Battle's sign, also mastoid ecchymosis, is an indication of fracture of middle cranial fossa of the skull, and may suggest underlying brain trauma. Battle's sign consists of bruising over the mastoid process, as a result of extravasation of blood along the path of the...
- is ecchymosisEcchymosisAn ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...
of the mastoid processMastoid processThe mastoid process is a conical prominence projecting from the undersurface of the mastoid portion of the temporal bone. It is located just behind the external acoustic meatus, and lateral to the styloid process...
of the temporal bone. - Raccoon eyesRaccoon eyesRaccoon eyes or periorbital ecchymosis is a sign of basal skull fracture, a craniotomy that ruptured the meninges, or certain cancers. Bilateral subconjunctival hemorrhage occurs when damage at the time of a facial fracture tears the meninges and causes the venous sinuses to bleed into the...
- is periorbital ecchymosisEcchymosisAn ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...
i.e. "black eyes" - Cerebrospinal fluid rhinorrhea
- Cranial nerve palsyPalsyIn medicine, palsy is the paralysis of a body part, often accompanied by loss of sensation and by uncontrolled body movements, such as shaking. Medical conditions involving palsy include cerebral palsy , brachial palsy , and Bell's palsy ....
- Bleeding from the nose and ears
- HemotympanumHemotympanumHemotympanum, or hematotympanum, refers to the presence of blood in the tympanic cavity of the middle ear. Hemotympanum is often the result of basilar skull fracture....
- conductive or perceptive deafness, nystagmus, vomitus
- In 1 to 10% of patients, ocular nerve entrapment occurs: the ocular nerve is pressed by The broken skull bones, causing irregularities in vision.
- Serious cases usually result in deathDeathDeath is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
Pathophysiology
Bones may be broken around the foramen magnum, the hole in the base of the skull through which the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
exits and becomes the brain stem
Brain stem
In vertebrate anatomy the brainstem is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves...
, creating the risk that blood vessels and nerves exiting the hole may be damaged.
Due to the proximity of the cranial nerves, injury to those nerves may occur. This can cause palsy
Palsy
In medicine, palsy is the paralysis of a body part, often accompanied by loss of sensation and by uncontrolled body movements, such as shaking. Medical conditions involving palsy include cerebral palsy , brachial palsy , and Bell's palsy ....
of the facial nerve
Facial nerve
The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...
or oculomotor nerve
Oculomotor nerve
The oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...
or hearing loss due to damage of cranial nerve VIII.
Management
Evidence does not support the use of prophylactic antibioticAntibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s regardless of the presence of a cerebral spinal fluid leak.
Prognosis
Non-displaced fractures usually heal without intervention. Patients with basilar skull fractures are especially likely to get meningitisMeningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
. Unfortunately, the role of prophylactic antibiotics in these cases is unclear.
Temporal bone fractures
Acute injury to the internal carotid arteryCarotid artery
Carotid artery can refer to:* Common carotid artery* External carotid artery* Internal carotid artery...
(carotid dissection, occlusion, pseudoaneurysm
Pseudoaneurysm
A pseudoaneurysm, also known as a false aneurysm, is a hematoma that forms as the result of a leaking hole in an artery. Note that the hematoma forms outside the arterial wall, so it is contained by the surrounding tissues. Also it must continue to communicate with the artery to be considered a...
formation) may be asymptomatic or result in life-threatening hemorrhage. They are almost exclusively observed when the carotid canal
Carotid canal
On the interior surface of the temporal bone, behind the rough surface of the apex, is the large circular aperture of the carotid canal, which ascends at first vertically, and then, making a bend, runs horizontally forward and medialward.-Contents:...
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.
Society and culture
Basilar skull fracture is a common cause of death in auto racing accidents:- Formula OneFormula OneFormula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...
driver Roland RatzenbergerRoland RatzenbergerRoland Ratzenberger was an Austrian racing driver who raced in Formula Nippon, Formula 3000 and Formula One...
in the 1994 San Marino Formula One Grand Prix1994 San Marino Grand PrixThe 1994 San Marino Grand Prix was a Formula One motor race held on May 1, 1994 at the Autodromo Enzo e Dino Ferrari, Imola, Italy. It was the third race of the 1994 Formula One season... - Indianapolis 500Indianapolis 500The Indianapolis 500-Mile Race, also known as the Indianapolis 500, the 500 Miles at Indianapolis, the Indy 500 or The 500, is an American automobile race, held annually, typically on the last weekend in May at the Indianapolis Motor Speedway in Speedway, Indiana...
drivers Bill VukovichBill VukovichBill Vukovich was a Serbian American automobile racing driver. He won the 1953 and 1954 Indianapolis 500 plus two more American Automobile Association National Championship races...
, Tony BettenhausenTony BettenhausenMelvin E. "Tony" Bettenhausen was an American racing driver, who won the National Championship in 1951 and 1958....
, Floyd RobertsFloyd RobertsFloyd Roberts is a former Championship Car racing driver from Jamestown, North Dakota. He won the Indianapolis 500 in 1938 with a record speed of . He led for 92 laps. The following year, 1939, driving the same car, he was killed in a crash on the backstretch after hitting a wooden fence at near...
, and Scott BraytonScott BraytonScott Everets Brayton was a race car driver from Coldwater, Michigan, on the American open-wheel circuit. He competed in 14 Indianapolis 500s, beginning with the 1981 event...
. - NASCARNASCARThe National Association for Stock Car Auto Racing is a family-owned and -operated business venture that sanctions and governs multiple auto racing sports events. It was founded by Bill France Sr. in 1947–48. As of 2009, the CEO for the company is Brian France, grandson of the late Bill France Sr...
drivers Dale Earnhardt Sr., Adam PettyAdam PettyAdam Kyler Petty was a professional racing driver. He was the first fourth-generation driver in NASCAR history.-Early life:...
, Tony RoperTony RoperAnthony Dean "Tony" Roper was a NASCAR driver. He was born in Springfield, Missouri, to Dean Roper and Shirley Medley. Growing up his family was heavily involved in auto racing. Roper started racing in 1986. For the next six years Tony raced in IMCA Modifieds and late models on Midwest dirt and...
, Kenny Irwin, Jr.Kenny Irwin, Jr.Kenneth Dale Irwin, Jr. was a NASCAR stock car driver. He had driven in all three major of forms of NASCAR and had two total victories. Before that, he raced in the United States Auto Club against Tony Stewart, who was one of his fiercest rivals...
, Neil BonnettNeil BonnettLawrence Neil Bonnett was a NASCAR driver who compiled 18 victories and 20 poles over his 18-year career. The Alabama native currently ranks 35th in all-time NASCAR Cup victories. He appeared in the 1983 film Stroker Ace and the 1990 film Days of Thunder...
, John NemechekJohn NemechekJohn Nemechek , was a race car driver who was killed in an accident during a Craftsman truck race at Homestead, Florida.-Life and racing career:...
, J. D. McDuffie, and Richie EvansRichie EvansRichard Ernest Evans , was an American racing driver who won nine NASCAR National Modified Championships, including eight in a row from 1978 to 1985. The International Motorsports Hall of Fame lists this achievement as "one of the supreme accomplishments in motorsports"...
. - CARTChamp CarChamp Car was the name for a class and specification of open wheel cars used in American Championship Car Racing for many decades, primarily for use in the Indianapolis 500 auto race...
drivers Jovy MarceloJovy MarceloEdward Jovy Marcelo was a Filipino race car driver from Quezon City, Philippines, who was killed in practice for the 1992 Indianapolis 500....
, Greg MooreGreg Moore (race car driver)Greg Moore was a racecar driver who competed in the Indy Lights and CART World Series, where he had great success with several wins in both series and a championship in the 1995 Indy Lights series...
and Gonzalo Rodriguez - ARCAAutomobile Racing Club of AmericaAutomobile Racing Club of America is an auto racing sanctioning body in the United States, founded in 1953 by John Marcum. The current president of ARCA is Ron Drager. The ARCA RE/MAX Series races stock cars similar to those seen in past years in the NASCAR Sprint Cup Series, and indeed most cars...
driver Blaise AlexanderBlaise AlexanderBlaise Alexander was a stock car racer from Montoursville, Pennsylvania. He began racing at the age of 12 in go-karts, winning the coveted World Karting Association East Regional championship in 1992. In 1995, he moved south to Mooresville, North Carolina and was named Rookie of the Year in the... - IndyCar driver Dan WheldonDan WheldonDaniel Clive "Dan" Wheldon was a British racing driver from England. He was the 2005 Indy Racing League IndyCar Series champion, and winner of the Indianapolis 500 in both 2005 and 2011...
.
To prevent this injury, all major motor sports sanctioning bodies now mandate the use of head and neck restraints, such as the HANS device
HANS device
The HANS device is a safety item compulsory in many car racing sports...
.