A skull fracture is a break in one or more of the eight bones that form the cranial portion of the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
, usually occurring as a result of
blunt force trauma
Blunt trauma, also known as blunt force trauma or non-penetrating trauma, is physical traumas, and particularly in the elderly who fall. It is contrasted with penetrating trauma which occurs when an object pierces the skin and enters a tissue ...
. If the force of the impact is excessive, the
bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
may fracture at or near the site of the impact and cause damage to the underlying structures within the skull such as the
membranes
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...
,
blood vessel
The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...
s, and
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
.
While an uncomplicated skull fracture can occur without associated physical or
neurological
Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal ...
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
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, o ...
. Any significant blow to the head results in a
concussion
A concussion, also known as a mild traumatic brain injury (mTBI), is a head injury that temporarily affects brain functioning. Symptoms may include loss of consciousness (LOC); memory loss; headaches; difficulty with thinking, concentration, ...
, with or without loss of
consciousness
Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
.
A fracture in conjunction with an overlying
laceration
A wound is a rapid onset of injury that involves lacerated or punctured skin (an ''open'' wound), or a contusion (a ''closed'' wound) from blunt force trauma or compression. In pathology, a ''wound'' is an acute injury that damages the epiderm ...
that tears the
epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...
and the
meninges
In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...
, or runs through the
paranasal sinuses
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoid ...
and the
middle ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear).
The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...
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
Comminuted may refer to:
*Comminution, the process in which solid materials are reduced in size, by crushing, grinding and other processes
*Bone fracture, as in a crushed or splintered bone
*Comminuted skull fracture
A skull fracture is a break ...
, 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.
Types
Linear fracture
Linear skull fractures are breaks in the bone that transverse the full thickness of the skull from the outer to inner table. They are usually fairly straight with no bone displacement. The common cause of injury is blunt force trauma where the impact energy transferred over a wide area of the skull.
Linear skull fractures are usually of little clinical significance unless they parallel in close proximity or transverse a
suture, or they involve a venous sinus groove or vascular channel. The resulting complications may include suture
diastasis,
venous sinus thrombosis
Cerebral venous sinus thrombosis (CVST), cerebral venous and sinus thrombosis or cerebral venous thrombosis (CVT), is the presence of a blood clot in the dural venous sinuses (which drain blood from the brain), the cerebral veins, or both. Sympt ...
, and
epidural hematoma
Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain (dura mater) and the skull. Often there is loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciou ...
. In young children, although rare, the possibility exists of developing a growing skull fracture especially if the fracture occurs in the
parietal bone
The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...
.
Depressed fracture
![Depressed skull fracture2](https://upload.wikimedia.org/wikipedia/commons/3/34/Depressed_skull_fracture2.jpg)
A depressed skull fracture is a type of fracture usually resulting from blunt force trauma, such as getting struck with a hammer, rock or getting kicked in the head. These types of fractures—which occur in 11% of severe head injuries—are comminuted fractures in which broken bones displace inward. Depressed skull fractures present a high risk of increased
pressure on the brain, or a hemorrhage to the brain that crushes the delicate tissue.
Compound depressed skull fractures occur when there is a laceration over the fracture, putting the internal cranial cavity in contact with the outside environment, increasing the risk of contamination and infection. In complex depressed fractures, the
dura mater
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...
is torn. Depressed skull fractures may require
surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
to lift the bones off the brain if they are pressing on it by making burr holes on the adjacent normal skull.
[Singh J and Stock A. 2006]
"Head Trauma."
Emedicine.com. Retrieved on January 26, 2007.
Diastatic fracture
![Cleidocranial2](https://upload.wikimedia.org/wikipedia/commons/a/a3/Cleidocranial2.jpg)
Diastatic fractures occur when the fracture line transverses
one or more sutures of the skull causing a widening of the suture. While this type of fracture is usually seen in infants and young children as the sutures are not yet fused it can also occur in adults. When a diastatic fracture occurs in adults it usually affects the
lambdoidal suture
The lambdoid suture (or lambdoidal suture) is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture.
Structure
Th ...
as this suture does not fully fuse in adults until about the age of 60. Most adult diastatic fractures are caused by severe head injuries. Due to the trauma, diastatic fracture occurs with the collapse of the surrounding head bones. It crushes the delicate tissue, similarly to a depressed skull fracture.
Diastatic fractures can occur with different types of fractures and it is also possible for diastasis of the cranial sutures to occur without a concomitant fracture. Sutural diastasis may also occur in various congenital disorders such as
cleidocranial dysplasia
Cleidocranial dysostosis (CCD), also called cleidocranial dysplasia, is a birth defect that mostly affects the bones and teeth. The collarbones are typically either poorly developed or absent, which allows the shoulders to be brought close togethe ...
and
osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
.
Basilar fracture
Basilar skull fracture
A basilar skull fracture is a break of a bone in the base of the skull. Symptoms may include bruising behind the ears, bruising around the eyes, or blood behind the ear drum. A cerebrospinal fluid (CSF) leak occurs in about 20% of cases and m ...
s are linear fractures that occur in the floor of the cranial vault (skull base), which require more force to cause than other areas of the neurocranium. Thus they are rare, occurring as the only fracture in only 4% of severe head injury patients.
Basilar fractures have characteristic signs: blood in the
sinuses
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoid ...
;
cerebrospinal fluid rhinorrhea
Cerebrospinal fluid rhinorrhoea (CSF rhinorrhoea) refers to the drainage of cerebrospinal fluid through the nose (rhinorrhoea). It is typically caused by a basilar skull fracture, which presents complications such as infection. It may be diagnosed ...
(
CSF leaking from the nose) or from the ears (cerebrospinal fluid otorrhea);
periorbital
The periorbita is the area around the orbit. Sometimes it refers specifically to the layer of tissue surrounding the orbit that consists of periosteum. However, it may refer to anything that is around the orbit, such as in periorbital cellulitis
...
ecchymosis
A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close e ...
often called '
raccoon eyes
Raccoon eyes (also known in the United Kingdom and Ireland as panda eyes) or periorbital ecchymosis is a sign of basal skull fracture or subgaleal hematoma, a craniotomy that ruptured the meninges, or (rarely) certain cancers. Bilateral hemorrhage ...
' (bruising of the orbits of the eyes that result from blood collecting there as it leaks from the fracture site); and retro
auricular ecchymosis known as "
Battle's sign
Battle's sign, also known as mastoid ecchymosis, is an indication of fracture of middle cranial fossa of the skull. These fractures may be associated with underlying brain trauma. Battle's sign consists of bruising over the mastoid process as a re ...
" (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
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...
. The skull fracture enlarges due, in part, to the rapid physiologic growth of the brain that occurs in young children, and brain
cerebrospinal fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates.
CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...
(CSF) pulsations in the underlying
leptomeningeal
In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...
cyst
A cyst is a closed sac, having a distinct envelope and cell division, division compared with the nearby Biological tissue, tissue. Hence, it is a cluster of Cell (biology), cells that have grouped together to form a sac (like the manner in which ...
ic 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
The scalp is the anatomical area bordered by the human face at the front, and by the neck at the sides and back.
Structure
The scalp is usually described as having five layers, which can conveniently be remembered as a mnemonic:
* S: The ski ...
.
Acute scalp swelling is associated with this type of fracture. In equivocal cases without immediate scalp swelling the diagnosis may be made via the use of
magnetic resonance imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
thus insuring more prompt treatment and avoiding the development of a "growing skull fracture".
Compound fracture
![Meninges-en](https://upload.wikimedia.org/wikipedia/commons/8/8e/Meninges-en.svg)
A fracture in conjunction with an overlying
laceration
A wound is a rapid onset of injury that involves lacerated or punctured skin (an ''open'' wound), or a contusion (a ''closed'' wound) from blunt force trauma or compression. In pathology, a ''wound'' is an acute injury that damages the epiderm ...
that tears the epidermis and the
meninges
In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...
—or runs through the
paranasal sinuses
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoid ...
and the
middle ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear).
The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...
structures, putting the outside environment in contact with the cranial cavity—is a compound fracture.
Compound fractures may either be clean or contaminated. Intracranial air (
pneumocephalus
Pneumocephalus is the presence of air or gas within the cranial cavity. It is usually associated with disruption of the skull: after head and facial trauma, tumors of the skull base, after neurosurgery or otorhinolaryngology, and rarely, spont ...
) may occur in compound skull fractures.
The most serious complication of compound skull fractures is infection. Increased risk factors for infection include visible contamination, meningeal tear, loose bone fragments and presenting for treatment more than eight hours after initial injury.
Compound elevated fracture
A compound elevated skull fracture is a rare type of skull fracture where the fractured bone is elevated above the intact outer table of the skull. This type of skull fracture is always compound in nature. It can be caused during an assault with a weapon where the initial blow penetrates the skull and the underlying meninges and, on withdrawal, the weapon lifts the fractured portion of the skull outward. It can also be caused by the skull rotating while being struck in a case of blunt force trauma, the skull rotating while striking an inanimate object as in a fall, or it may occur during transfer of a patient after an initial compound head injury.
Anatomy
The human skull is anatomically divided into two parts: the
neurocranium
In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria (skull), ...
, formed by eight cranial bones that houses and protect the brain—and the facial skeleton (
viscerocranium) composed of fourteen bones, not including the three
ossicle
The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ...
s of the inner ear. The term ''skull fracture'' typically means fractures to the neurocranium, while fractures of the facial portion of the skull are ''
facial fracture
Facial trauma, also called maxillofacial trauma, is any physical trauma to the face. Facial trauma can involve soft tissue injuries such as burns, lacerations and bruises, or fractures of the facial bones such as nasal fractures and fractur ...
s'', or if the jaw is fractured, a ''
mandibular fracture
Mandibular fracture, also known as fracture of the jaw, is a break through the mandibular bone. In about 60% of cases the break occurs in two places. It may result in a decreased ability to fully open the mouth. Often the teeth will not feel pr ...
''.
The eight cranial bones are separated by
sutures : one
frontal bone
The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, par ...
, two
parietal bone
The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...
s, two
temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. Th ...
s, one
occipital bone
The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobe ...
, one
sphenoid bone
The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...
, and one
ethmoid bone
The ethmoid bone (; from grc, ἡθμός, hēthmós, sieve) is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a ...
.
The bones of the skull are in three layers: the hard compact layer of the external table (''
lamina externa''), the
diploë
Diploë ( or ) is the spongy cancellous bone separating the inner and outer layers of the cortical bone of the skull.
In the cranial bones, the layers of compact cortical tissue are familiarly known as the tables of the skull; the outer one is ...
(a spongy layer of
red bone marrow
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...
in the middle, and the compact layer of the inner table (''Lamina interna'').
Skull thickness is variable, depending on location. Thus the traumatic impact required to cause a fracture depends on the impact site. The skull is thick at the
glabella
The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to ...
, the
external occipital protuberance
Near the middle of the squamous part of occipital bone is the external occipital protuberance, the highest point of which is referred to as the inion. The inion is the most prominent projection of the protuberance which is located at the posterioin ...
, the
mastoid process
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, t ...
es, and the external angular process of the frontal bone. Areas of the skull that are covered with muscle have no underlying diploë formation between the internal and external lamina, which results in thin bone more susceptible to fractures.
Skull fractures occur more easily at the thin squamous
temporal and
parietal bone
The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...
s, the
sphenoid sinus
The sphenoid sinus is a paired paranasal sinus occurring within the within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, ...
, the
foramen magnum
The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblon ...
(the opening at the base of the skull that the spinal cord passes through), the
petrous temporal ridge, and the inner portions of the
sphenoid wings at the base of the skull. The
middle cranial fossa
The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest.
It is bounded in front by the pos ...
, a depression at the base of the cranial cavity forms the thinnest part of the skull and is thus the weakest part. This area of the cranial floor is weakened further by the presence of multiple
; as a result this section is at higher risk for basilar skull fractures to occur. Other areas more susceptible to fractures are the
cribriform plate
In mammalian anatomy, the cribriform plate (Latin for lit. ''sieve-shaped''), horizontal lamina or lamina cribrosa is part of the ethmoid bone. It is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities. It supp ...
, the roof of orbits in the
anterior cranial fossa
The anterior cranial fossa is a depression in the floor of the cranial base which houses the projecting frontal lobes of the brain. It is formed by the orbital part of frontal bone, orbital plates of the Frontal bone, frontal, the cribriform plate ...
, and the areas between the mastoid and
dural sinuses in the
posterior cranial fossa
The posterior cranial fossa is part of the cranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum.
This is the most inferior of the fossae. It houses the cerebellum, medulla and pons. ...
.
Prognosis
Children with a simple skull fracture without other concerns are at low risk of a bad outcome and rarely require aggressive treatment.
The presence of a concussion or skull fracture in people after trauma without intracranial
hemorrhage
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
or
focal neurologic deficits was indicated in long term cognitive impairments and emotional lability at nearly double the rate as those patients without either complication.
Those with a skull fracture were shown to have "neuropsychological dysfunction, even in the absence of intracranial pathology or more severe disturbance of consciousness on the GCS".
See also
*
Le Fort facial fracture
*
Facial fracture
Facial trauma, also called maxillofacial trauma, is any physical trauma to the face. Facial trauma can involve soft tissue injuries such as burns, lacerations and bruises, or fractures of the facial bones such as nasal fractures and fractur ...
*
Mandibular fracture
Mandibular fracture, also known as fracture of the jaw, is a break through the mandibular bone. In about 60% of cases the break occurs in two places. It may result in a decreased ability to fully open the mouth. Often the teeth will not feel pr ...
References
Bibliography
* Forensic Neuropathology By Jan E. Leestma Publisher: CRC Press; 2 edition (October 14, 2008) Language: English
* Neuroimaging: Clinical and Physical Principles By Robert A. Zimmerman, Wendell A. Gibby, Raymond F. Carmody Publisher: Springer; 1st edition (January 15, 2000) Language: English
External links
Medscape: Imaging in Skull Fractures*
ttps://web.archive.org/web/20051106231525/http://www.radiology.co.uk/srs-x/tutors/cttrauma/tutor.htm "Tutorial: CT in Head Trauma"Head Trauma at Emedicine.comSkull Fractures at MedPix
{{DEFAULTSORT:Skull Fracture
Bone fractures
Neurotrauma
Injuries of head