Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

2,503 results found
Article

Emery-Dreiffus muscular dystrophy

Emery-Dreifuss muscular dystrophy is a rare muscular dystrophy characterized by childhood onset of contractures, humeroperoneal muscle atrophy, and cardiac conduction abnormalities.  Clinical course Weakness is slowly progressive, but there is a broad spectrum of clinical severity.  Pathology...
Article

Emissary veins

Emissary veins (also known as the vena emissaria) are small valveless, thin-walled veins that pass via the foramina of the skull, providing a venous communication between the dural venous sinuses and veins of the scalp or veins inferior to the skull base (cranial-cerebral anastomosis). Thus, the...
Article

Empty delta sign (dural venous sinus thrombosis)

The empty delta sign is a CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect, which represents thrombus. It is only described with CECT-scan or MRI, not with NECT nor non-contrast MRI. An equivalent appearance can be note...
Article

Empty light bulb sign (brain death)

In brain death, on Tc-99m HMPAO imaging there is absent or reduced flow in the internal carotid arteries and increased flow within the external carotid arteries. This leads to absent uptake in the brain with subsequent increased perfusion in the nasal region. This appearance has been called the ...
Article

Empty sella

An empty sella, also known as an empty pituitary fossa, is a relatively common incidental finding and posed more of a diagnostic problem before modern cross-sectional imaging. In addition to being incidental, a well-established association with benign intracranial hypertension is also recognized...
Article

Empty thecal sac sign

The empty thecal sac sign or empty sac sign is when the thecal sac appears empty on MRI of the lumbar spine, best seen on T2-weighted images. If the empty thecal sac sign is present, a diagnosis of adhesive arachnoiditis can be made.​ Radiographic features MRI There is usually no gadolinium c...
Article

Empyema

Empyemas are purulent inflammatory collections within a body cavity. Contrast this with abscesses, which arise within parenchymal tissue, rather than occupying a pre-existing anatomical space. Terminology Colloquially, the standalone term empyema is used to refer to thoracic empyemas but there...
Article

Encephalitis due to herpesvirus family

Although sporadic viral encephalitis is most commonly due to herpes simplex virus 1 (HSV-1) the extended herpesvirus family consists of many other viruses many of which can also infect the central nervous system. Encephalitis due to herpesvirus family include 1:   herpes simplex virus 1 (HSV-1)...
Article

Encephalitis lethargica

Encephalitis lethargica, also known as von Economo encephalitis, is a rare disease of unknown etiology that affects the midbrain and basal ganglia.  Clinical presentation Symptoms are initially that of pharyngitis followed by lethargy, extrapyramidal movements (parkinsonism and dyskinesias), n...
Article

Encephalocele

Encephalocele, also known as meningoencephalocele, is a form of neural tube defect and a type of cephalocele where brain tissue and overlying meninges herniate out through a defect in the cranium.  Terminology It should be distinguished from cranial meningocele in which the lesion contains onl...
Article

Encephalocraniocutaneous lipomatosis

Encephalocraniocutaneous lipomatosis (ECCL), also known as Haberland syndrome, is a rare congenital neurocutaneous syndrome characterized by unilateral lipomas of the cranium, face, and neck, ipsilateral lipodermoids of the eye, and ipsilateral brain anomalies. The clinical features of ECCL ove...
Article

Encephaloduroarteriomyosynangiosis

Encephaloduroarteriomyosynangiosis (EDAMS) is a surgical procedure performed most commonly in children with moyamoya disease or less commonly in individuals with intracranial atherosclerotic disease as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or ...
Article

Encephaloduroarteriosynangiosis

Encephaloduroarteriosynangiosis (EDAS) is a surgical procedure performed most commonly in children with moyamoya disease or less commonly in individuals with intracranial atherosclerotic disease as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or circ...
Article

Encephalomalacia

Encephalomalacia is term given to describe softening or loss of brain parenchyma with or without surrounding gliosis, as a late manifestation of injury.  Clinical presentation asymptomatic  serve as a focus of seizure Pathology Encephalomalacia is the end result of liquefactive necrosis of ...
Article

Encephalomyosynangiosis

Encephalomyosynangiosis (EMS) is a surgical procedure performed most commonly in children with moyamoya disease as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or circle of Willis vessels 1.  It entails dissecting strips of vascularized temporalis m...
Article

Endolymphatic sac tumor

Endolymphatic sac tumors (ELSTs) are very rare, locally invasive tumors of endolymphatic sac. Early detection of these tumors is critical, because early surgical intervention may prevent further hearing loss. Endolymphatic sac tumors do not metastasize but are highly locally aggressive.  Epidem...
Article

Enlarged posterior fossa 'CSF' space

An enlarged posterior fossa 'CSF' space posterior to the cerebellum has a number of differentials that include: mega cisterna magna epidermoid cyst arachnoid cyst Careful attention to the cerebellum needs to paid as also to be considered are: cerebellar atrophy Dandy-Walker malformations ...
Article

Enlarged sella turcica (differential)

Enlargement of sella turcica can be seen in situations including the following: empty sella syndrome slight globular enlargement of the sella with no erosion, destruction or posterior displacement of dorsum sellae intracranial hypertension enlargement with erosion of anterior cortex of dorsu...
Article

En plaque meningioma

En plaque meningiomas refer to a specific meningioma macroscopic appearance characterized by diffuse and extensive dural involvement, usually with extracranial extension into calvarium, orbit, and soft tissues. These tumors are thought to have a collar-like or sheet-like growth along the dura ma...
Article

Enterovirus 71

Enterovirus 71 is one of the viruses that causes hand-foot-and-mouth disease in children. It is an enterovirus, one of the picornaviruses. Infection with enterovirus 71 predominantly results in a vesicular rash of the hands and feet that follows a prodrome of symptoms including fever, vomiting ...
Article

Enterovirus rhombencephalitis

Enterovirus rhombencephalitis is the most common neurological complication of enterovirus infection 1. Clinical presentation Enterovirus rhombencephalitis causes acute and severe neurologic disorders such as ataxia, nystagmus, oculomotor palsies, or bulbar palsy. In some cases, neurologic affe...
Article

Entorhinal cortex

The entorhinal cortex (Brodmann area 28) is located in the mesial temporal lobe and acts as the interface between the hippocampus and the neocortex. It has been considered part of the hippocampal formation (along with Ammon’s horn, subiculum and presubiculum), but is difficult to precisely local...
Article

Eosinophilia myalgia syndrome

Eosinophilia myalgia syndrome (EMS) is a fatal neurological condition caused by ingestion of improperly manufactured L-tryptophan. Impurities and/or metabolites that block histamine degradation result in peripheral blood eosinophilia and myalgia.  In the brain, cortical and basal ganglia atroph...
Article

Ependymal cells

Ependymal cells are one of the four main types of glial cells, and themselves encompass three types of cells 1:  ependymocytes: line the ventricles of the brain and central canal of the spinal cord tanycytes: line the floor of the third ventricle overlying the median eminence of the hypothalam...
Article

Ependymal cyst

Ependymal cysts are rare benign neuroepithelial cysts lined by ependymal cells. Most are small and asymptomatic and only cause symptoms if large. On imaging, these cysts are essentially indistinguishable from other intraventricular simple cysts (e.g. intraventricular arachnoid cysts). Epidemio...
Article

Ependymal dot-dash sign

The ependymal dot-dash sign has been described as an early MRI imaging feature of multiple sclerosis before other more florid white matter changes (e.g. Dawson's fingers) become evident 1. It has also been suggested as a feature that can be used to distinguish multiple sclerosis from neuromyelit...
Article

Ependymal rosettes (ependymoma)

Ependymal rosettes correspond to a histologic architectural pattern that very characteristic of ependymomas, as tumor cells form structures similar to the lining of normal ventricles. They are characterized by a halo or spoke-wheel arrangement of tumor cells surrounding an empty central tubule l...
Article

Ependymitis granularis

Ependymitis granularis sounds far more worrying than it actually is. The term refers to symmetrical foci of periventricular high T2 and FLAIR signal hyperintensity anterior and lateral to the frontal horns. It is just an anatomical variant, usually small, less than 1 cm, and has a triangular mor...
Article

Ependymocytes

Ependymocytes are one of the three types of ependymal cells, which in turn are one of the four principles types of glial cells, and are found lining the ventricular system of the brain and the central canal of the spinal cord 1.  They do not form a water-tight barrier between the cerebrospinal ...
Article

Ependymoma

Ependymomas represent a relatively broad group of glial tumors most often arising from the lining the ventricles of the brain or the central canal of the spinal cord. They account for ~5% of all neuroepithelial neoplasms, ~10% of all pediatric brain tumors and up to 33% of brain tumors occurring...
Article

Ependymoma RELA fusion-positive

Ependymoma RELA fusion-positive is a recently accepted molecular variant of ependymoma, only recognized in the 2016 update to the WHO classification of CNS tumors. They are the most common type of supratentorial ependymoma in children, and not found in the posterior fossa or spinal cord.  Epide...
Article

Ependymoma vs astrocytoma of the spinal cord

A number of factors are useful when differentiating between spinal cord ependymoma and spinal cord astrocytoma.  Ependymoma child or adult more central in location bone remodelling is common low T1 signal well-defined enhancement syrinx is more common hemorrhage is more common Astrocyto...
Article

Epidermoid cyst

Epidermoid cysts are nonneoplastic inclusion cysts derived from ectoderm that are lined solely by squamous epithelium. These are discussed separately by anatomic location: epidermal inclusion cyst intracranial epidermoid cyst splenic epidermoid cyst spinal epidermoid cyst testicular epiderm...
Article

Epidural angiolipoma

Epidural angiolipomas are rare benign tumors composed of mature adipocytes and abnormal vessels.  Epidemiology Epidural angiolipomas are more frequently encountered in women, and typically in middle age (40-50 years of age) 1.  Clinical presentation In keeping with the slow growth of these t...
Article

Epidural blood patch

Epidural blood patch is a treatment option for patients with craniospinal hypotension or post lumbar puncture headaches. The procedure can be done blind or under fluoroscopic or CT guidance, and is performed predominantly by radiologists and anesthesiologists.  Indications craniospinal hypoten...
Article

Epidural ligaments

The epidural ligaments, also known as meningovertebral ligaments, are variably thick bands of connective tissue located within the spinal epidural space attaching the outer surface of the theca to the inner borders of the spinal canal (vertebrae and ligaments).  They are somewhat variable in nu...
Article

Epidural lipomatosis

Epidural lipomatosis refers to an excessive accumulation of fat within the spinal epidural space resulting in compression of the thecal sac. In severe cases, compression may be symptomatic. The lumbar region is most frequently affected. Epidemiology The demographics of affected individuals ref...
Article

Epilepsy

Epilepsy is a common neurological disorder that has a varied presentation and requires two or more unprovoked seizures at least 24 hours apart for diagnosis. MRI is the modality of choice for epilepsy, most often investigating for an underlying cause, especially in adults.  Epidemiology Epilep...
Article

Epilepsy protocol (MRI)

MRI protocol for epilepsy is a group of MRI sequences put together to improve sensitivity and specificity in identifying possible structural abnormalities that underlie seizure disorders (e.g. mesial temporal sclerosis and malformation of cortical development). MRI is the imaging procedure of ch...
Article

Epiphora

Epiphora (plural: epiphoras) represents excessive tearing of the eye and is a common clinical presentation to ophthalmological practice. It is most frequently due to an obstruction of the nasolacrimal drainage apparatus. Less commonly, overproduction of tears may be responsible.  Epidemiology ...
Article

Episodic spontaneous hypothermia with hyperhidrosis syndrome

Episodic spontaneous hypothermia with hyperhidrosis syndrome (ESHH) is a rare syndrome characterized by periodic hypothermia and hyperhidrosis. This occurs in the absence of agenesis of the corpus callosum, thus differentiating it from Shapiro syndrome 1. Epidemiology Episodic spontaneous hypo...
Article

Epithalamus

The epithalamus is a dorsal posterior segment of the diencephalon that includes the habenula, stria medullaris, pineal gland, and posterior commissure. Its function is the connection between the limbic system to other parts of the brain.
Article

Epithelial membrane antigen (EMA)

Epithelial membrane antigen (EMA) is a commonly used target for immunohistochemisty, found on the surface of many epithelial cells and thus present in a wide variety of tumors. It also is sometimes seen within the cytoplasm of cells (e.g. perinuclear dot in ependymomas). 
Article

Epithelioid glioblastoma

Epithelioid glioblastoma is a variant of glioblastoma (along with gliosarcoma and giant cell glioblastoma) only recently added to the WHO classification of CNS tumors as part of the 2016 update 1.  Terminology Whether or not epithelioid glioblastomas are distinct from rhabdoid glioblastomas is...
Article

Epstein-Barr virus encephalitis

Epstein-Barr virus (EBV) encephalitis is an uncommon manifestation of EBV infection and an uncommon causative organism of encephalitis in general. Epidemiology Most reported cases have been in children, although adults can rarely be affected 5. Clinical presentation Primary EBV infection is ...
Article

Erdheim-Chester disease

Erdheim-Chester disease is a rare non-Langerhans cell, non-familial multisystemic histiocytosis, with widespread manifestations and of highly variable severity. The most common presenting symptom is bone pain. Epidemiology Erdheim-Chester disease is a rare, non-inherited disease of middle age ...
Article

État criblé

État criblé, also known as status cribrosum, is a term that describes the diffusely widened perivascular spaces (Virchow-Robin spaces) in the basal ganglia, especially in the corpus striatum on MRI. It is usually symmetrical, with the perivascular spaces showing CSF signal and without diffusion ...
Article

État lacunaire

État lacunaire is a term describing the presence of multiple lacunar infarcts, which are ischemic strokes due to occlusion of penetrating cerebral arterioles, especially in the basal ganglia. The term has been strongly described as a pathological substrate for a multi-infarct vascular dementia 4...
Article

Ethylene glycol toxicity

Ethylene glycol toxicity is a type of toxic leukoencephalopathy. Ethylene glycol, best known as a component of antifreeze, has been ingested both deliberately and accidentally, resulting in neurotoxicity and renal failure. Clinical presentation A delay is present between ingestion and developm...
Article

Evans' index

The Evans' index is the ratio of maximum width of the frontal horns of the lateral ventricles and the maximal internal diameter of the skull at the same level employed in axial CT and MRI images. This ratio varies with the age and sex. It is useful as a marker of ventricular volume and thus has...
Article

Exencephaly

Exencephaly is a lethal congenital fetal brain developmental anomaly (neural tube defect) considered to be a precursor to anencephaly in the acrania-exencephaly-anencephaly sequence. Pathology It is characterized by calvarial absence and loss of fetal brain tissue to variable degrees and is co...
Article

Expanded treatment in cerebral ischemia (eTICI) score

The expanded treatment in cerebral infarction (eTICI) score was further modified from the modified treatment in cerebral infarction (mTICI) and thrombolysis in cerebral infarction (TICI) scale by the HERMES investigators in 20191. Using modified Rankin scale (mRs) shift at 90 days as the outcome...
Article

External auditory canal atresia

External auditory canal atresia (EACA) is characterized by complete or incomplete bony atresia of the external auditory canal (EAC) and, especially when seen in the setting of an associated syndrome, a dysplastic auricle and an abnormal middle ear cavity. Epidemiology The incidence is 1 in 10,...
Article

External capsule

The external capsule is a series of white matter tracts in the brain situated between the putamen and claustrum. It is composed of claustrocortical fibers dorsally and the combined mass of the uncinate fasciculus and inferior frontal occipital fasciculus ventrally. Relationships The putamen se...
Article

External petrosal nerve

The external petrosal nerve is one of the three branches from the geniculate ganglion. It carries sympathetic fibers to the middle meningeal artery.
Article

External ventricular drain

External ventricular drains (EVDs) are a common neurosurgical procedure used to monitor and treat raised intracranial pressure in the acute setting.  Treatment and prognosis Complications infection EVD malfunction EVD malposition intracranial hemorrhage (e.g. subdural, intraventricular) s...
Article

Extra-axial

Extra-axial is a descriptive term to denote lesions that are external to the brain parenchyma, in contrast to intra-axial which describes lesions within the brain substance.  Radiographic features Often it is trivially easy to distinguish an intra-axial from an extra-axial mass. In many cases,...
Article

Extra-axial collection (summary)

This is a basic article for medical students and other non-radiologists Extra-axial collections are collections of fluid within the skull, but outside the brain parenchyma. They may be comprised of CSF, blood or pus and may exist in the extradural, subdural or subarachnoid space.  Reference ar...
Article

Extra-axial masses (differential)

Extra-axial masses of the intracranial compartment have a wide range of differentials, ranging from benign developmental cysts to malignant tumors.  Differential diagnosis neoplasms chordoma choroid plexus papilloma/carcinoma cranial nerve schwannoma meninges meningioma solitary fibrous ...
Article

Extraconal orbital lesions

Extraconal orbital lesions include lesions which arise from structures within the extraconal orbital space and those extending from adjacent structures into the orbits. Differential diagnosis Intraorbital lesions dermoid cyst: most common lesion in pediatrics  lacrimial gland lesions dacryo...
Article

Extracranial brain herniation

Extracranial brain herniation refers to herniation of brain tissue external to the calvaria through a skull bone defect, which may be post-traumatic or post-surgical. Unlike encephaloceles, brain herniation is not surrounded by the meninges.  Craniectomy may be performed to decompress intracran...
Article

Extracranial meningioma

Extracranial meningiomas, also known as primary extradural meningiomas are a form of ectopic meningioma, are a rare location-specific type of meningioma that arise outside the dural covering of the brain and spinal cord. They are essentially extracranial tumors, most often occurring in the head ...
Article

Extradural hematoma vs subdural hematoma

Differentiating extradural (EDH) from subdural (SDH) hemorrhage in the head is usually straightforward, but occasionally it can be challenging. SDHs are more common and there are a few distinguishing features which are usually reliable. Pathology History and mechanism of injury Extradural hem...
Article

Extradural hemorrhage

Extradural hematoma (EDH), also known as an epidural hematoma, is a collection of blood that forms between the inner surface of the skull and outer layer of the dura, which is called the endosteal layer. They are usually associated with a history of head trauma and frequently associated skull fr...
Article

Extradural hemorrhage (summary)

This is a basic article for medical students and other non-radiologists Extradural hemorrhages (EDH) represent collections of blood in the extradural (epidural) space. The hemorrhage sits between the skull superficially and the dura which overlies the brain parenchyma. The bleed in relation to...
Article

Extradural hemorrhage (venous)

Venous extradural hemorrhages are a relatively uncommon subtype of extradural hemorrhages, differing from arterial extradural hemorrhages not only in etiology, but also location and prognosis.  They occur as a result of damage to the dural venous sinuses and often result in the displacement of ...
Article

Extradural neural axis compartment

Extradural neural axis compartment (EDNAC) exists from the tip of the coccyx all the way to the back of the globe, and yet it is relatively unknown as a concept. It is bounded externally by the periosteum of the vertebrae and sacrum inferiorly and the skull superiorly, and the visceral layer of ...
Article

Extradural space

The extradural (epidural) space is a potential space between the cranial bones and the endosteal layer of the dura mater, which is otherwise adherent to the cranial bone.  Gross anatomy The extradural space is a potential space inside the cranial vault and is not normally appreciable unless th...
Article

Extraneural spread of intracranial neoplasm

Extraneural spread of primary intracranial neoplasm is distinctly uncommon, occurring far less frequently than CSF spread.  The most frequent neoplasms to do so, in decreasing order of frequency, are: glioblastoma (GBM) meningioma medulloblastoma
Article

Extraocular muscle involvement in thyroid associated orbitopathy (mnemonic)

A mnemonic to remember the order in which extraocular muscles are involved in thyroid-associated orbitopathy (TAO) is: I'M SLOw Mnemonic I: inferior rectus M: medial rectus S: superior rectus L: lateral rectus O: obliques muscles (superior oblique and inferior oblique) There is some deba...
Article

Extraocular muscle nerve supply (mnemonic)

A mnemonic to remember the nerve supply to the extraocular muscles: LR6SO4O3 (mock 'chemical formula') Mnemonic The letters represent the extraocular muscles and numbers represent their respective cranial nerve supply: LR6: lateral rectus, innervated by the 6th (abducens) nerve  SO4: superi...
Article

Extrapontine myelinolysis

Extrapontine myelinolysis (EPM) is one of the complications occurring secondary to rapid correction of hyponatremia, and is, along with central pontine myelinolysis encompassed by the more recent term osmotic demyelination syndrome. In the vast majority of cases it is associated with central po...
Article

Extrapulmonary tuberculosis

Extrapulmonary tuberculosis (TB) refers to the haematogenous spread of Mycobacterium tuberculosis. Pathology Extrapulmonary tubercuosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can ...
Article

Extrapyramidal system

The extrapyramidal system is the part of the motor system involved in modulation and regulation of movement. As its name suggests, it is distinct from the motor fibers that are relayed through the pyramids of the medulla oblongata (corticospinal and corticobulbar tracts). It is composed of nerv...
Article

Extraventricular neurocytoma

Extraventricular neurocytomas, previously known as cerebral neurocytomas, are rare WHO grade II primary CNS neoplasms usually arising in the cerebral hemispheres. They are, as the name implies, extraventricular versions of central neurocytomas.  Epidemiology These tumors are reported at essent...
Article

Extreme capsule

The extreme capsule is a series of white matter tracts in the brain that run between the claustrum and insular cortex.
Article

Eye of the tiger sign (globus pallidus)

The eye of the tiger sign refers to abnormal low T2 signal on MRI (due to abnormal accumulation of iron) in the globus pallidus with a longitudinal stripe of high signal (due to gliosis and spongiosis).  The eye of the tiger sign is most classically associated with pantothenate kinase-associate...
Article

F-18 fluorodeoxyglucose

F-18 fluorodeoxyglucose (FDG) is the most common PET radiotracer. Structure The radiopharmaceutical consists of the fluorine-18 radionuclide substituting the hydroxyl group at the C-2 position of glucose. The IUPAC chemical name is 2-deoxy-2-[F-18]fluoroglucose. Production F-18 fluoride ion ...
Article

Fabry disease

Fabry disease, also known as Anderson-Fabry disease, is a multisystem disorder resulting from an X-linked inborn error of metabolism and is a lysosomal storage disorder. The disease results from genetic mutations that cause decreased or absent expression of hydrolase alpha-galactosidase A, ultim...
Article

Facial-cavernous anastomoses

The facial-cavernous anastomoses are the communications of the facial and deep facial veins with the cavernous sinus. Gross anatomy At the medial canthus of the eye there is a communication with the ophthalmic veins, which drain into the cavernous sinus. Blood from the frontal scalp normally f...
Article

Facial colliculus

The facial colliculus is an elevation on the floor of the fourth ventricle and is not formed by the facial nerve nucleus, but by the fibers of the facial nerve arching backwards around the abducens nerve (CN VI) nucleus before turning forwards once more in the caudal pons. Related pathology A ...
Article

Facial colliculus syndrome

Facial colliculus syndrome refers to a constellation of neurological signs due to a lesion at the facial colliculus, involving: abducens nerve (CN VI) nucleus facial nerve (CN VII) fibers at the genu medial longitudinal fasciculus Clinical presentation lower motor neuron facial nerve palsy ...
Article

Facial nerve

The facial nerve is one of the key cranial nerves with a complex and broad range of functions. Although at first glance it is the motor nerve of facial expression which begins as a trunk and emerges from the parotid gland as five branches (see facial nerve branches mnemonic), it has taste and p...
Article

Facial nerve branches (mnemonic)

There are many mnemonics to recall the branches of the facial nerve (superior to inferior) as they exit the anterior border of the parotid gland. Examples include: Tall Zulus Bear Many Children Two Zebras Bit My Coccyx Ten Zebras Buggered My Car To Zanzibar By Motor Car Two Zombies Buggered...
Article

Facial nerve choristoma

Facial nerve choristomas are rare, being characterized by non-neoplastic proliferation of smooth muscle cells and fibrous tissue. Facial nerve choristomas presumably can occur anywhere along the course of the facial nerve (CN VII), although the only cases reported are in the internal acoustic me...
Article

Facial nerve schwannoma

Facial nerve schwannoma (FNS), also known as facial nerve neuroma/neurilemoma, is a schwannoma that arises from the facial nerve. They are generally uncommon, and when involving the temporal bone, make up less than 1% of all temporal bone tumors. Epidemiology FNS is a rare tumor 2. Clinical p...
Article

Facial nerve segments (mnemonic)

Helpful mnemonics for remembering the segments of the facial nerve include: I Love Going To Makeover Parties 1 I Love Grinning, Then Making Pouts both grinning and pouting are performed by muscles which are innervated by the facial nerve I Must Learn To Make (facial) Expressions Mnemonics ...
Article

Facial palsy

Facial palsy refers to the neurological syndrome of facial paralysis. It can result from a broad range of physiological insults to the facial nerve or its central nervous system origins. The most common causes of this is Bell palsy.  Terminology While facial palsy refers to the clinical presen...
Article

Fahr syndrome

Fahr syndrome, also known as bilateral striatopallidodentate calcinosis, is characterized by abnormal vascular calcium deposition, particularly in the basal ganglia, cerebellar dentate nuclei, and white matter, with subsequent atrophy. It can be either primary (usually autosomal dominant) or se...
Article

Falciform crest

The falciform crest, also known as the crista falciformis, is a horizontal ridge that divides the lateral portion of the internal acoustic meatus (IAM) into superior and inferior portions. Superior The facial nerve (VII) and superior vestibular nerve (SVN) travel in the superior portion of the...
Article

Falx cerebelli

The falx cerebelli is a small infolding of the dura in the sagittal plane over the floor of the posterior cranial fossa. It partially separates the two cerebellar hemispheres 1. Gross anatomy The falx cerebelli is attached posteriorly in the midline to the internal occipital crest of the occip...
Article

Falx cerebri

The falx cerebri (plural: falxes/falces cerebrorum) is the largest of the four main folds (or septa) of the intracranial dura mater, separating the cerebral hemispheres 1.  Gross anatomy The falx cerebri is a double-fold of dura mater that descends through the interhemispheric fissure in the m...
Article

Falx ossification

In discussing mineralization of the falx cerebri, many radiology textbooks use the term falx calcification and make no mention of falx ossification.  Epidemiology Ossification of dural folds is relatively unusual; one study suggested a prevalence of falx ossification of 0.7% 1. Even though, os...

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.