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.

2,131 results found
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Foramen caecum (disambiguation)

Foramen caecum can refer to a number of different anatomical structures: foramen caecum (tongue) foramen caecum (anterior cranial fossa)
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Foramen magnum

The foramen magnum is the largest foramen of the skull and is part of the occipital bone 1. It is oval in shape with a large antero-posterior diameter 2. Gross anatomy The foramen magnum is found in the most inferior part of the posterior cranial fossa 3. It is traversed by vital structures in...
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Foramen of Magendie

The foramen of Magendie (also called median aperture) is one of the foramina in the ventricular system and links the fourth ventricle and the cisterna magna. It is one of the three ways that cerebrospinal fluid (CSF) can leave the fourth ventricle and enter the subarachnoid space. The two other ...
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Foramen ovale (skull)

Foramen ovale is an oval shaped opening in the middle cranial fossa located at the posterior base of the greater wing of the sphenoid bone, lateral to the lingula. It transmits the mandibular division of the trigeminal nerve (CN Vc), accessory meningeal artery, emissary veins between the caverno...
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Foramen rotundum

The foramen rotundum is located in the middle cranial fossa, inferomedial to the superior orbital fissure at the base of greater wing of the sphenoid bone. Its medial border is formed by lateral wall of sphenoid sinus. It runs downwards and laterally in an oblique path and joins the middle crani...
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Foramen spinosum

The foramen spinosum is located in the posteromedial part of greater wing of sphenoid bone posterolateral to foramen ovale which connects the middle cranial fossa with the infratemporal fossa. It transmits the middle meningeal artery, middle meningeal vein, and (usually) the nervus spinosus. Va...
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Forceps major

The forceps major, also known as the posterior forceps, is a fibre bundle which connects the occipital lobes and crosses the midline via the splenium of the corpus callosum. 
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Forceps minor

The forceps minor, also known as the anterior forceps, is a fibre bundle which connects the lateral and medial surfaces of the frontal lobes and crosses the midline via the genu of the corpus callosum.
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Fornix (brain)

The fornix is the main efferent system of the hippocampus and an important part of the limbic system. It is one of the commissural fibres connecting the cerebral hemispheres. Gross anatomy Roughly C-shaped, the fornix extends from the hippocampus to the mammillary bodies of the hypothalamus an...
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Fornix (disambiguation)

The term fornix (plural: fornices) is used for anatomical structures in multiple organ systems that all share an arch-like morphology: fornix (brain) fornix (eye) fornix (lacrimal) fornix (pharynx) fornix (renal) fornix (stomach) fornix (vagina) History and etymology Fornix is Latin for...
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Fornix (eye)

The fornix conjunctiva is loose soft tissue lying at the junction between the palpebral conjunctiva (covering the inner surface of the eyelid) and the bulbar conjunctiva (covering the globe). Each eye has two fornices, the superior and inferior fornices. The fornix permits freedom of movement of...
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Foster Kennedy syndrome

Foster Kennedy syndrome describes the clinical syndrome of unilateral optic atrophy with contralateral papilloedema caused by an ipsilateral compressive mass lesion. Clinical presentation The syndrome consists of two cardinal features: ipsilateral optic nerve atrophy presenting with central s...
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Fourth ventricle

The fourth ventricle is one of the components of the ventricular system in the brain, along with the lateral and third ventricles. It extends from the cerebral aqueduct (of Sylvius) to the obex and is filled with CSF. CSF enters the ventricle via the cerebral aqueduct and leaves via one of four...
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Fourth ventriculocoele

A fourth ventriculocoele is large posterior fossa cyst which remodels, thins and eventually erodes through the occipital bone to form an occipital encephalocoele. It may be classified as part of the Dandy-Walker continuum, but this is controversial.
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Fracture-a-la-signature (skull fracture)

Fracture-a-la-signature (or signature fracture) is another term used to described a depressed skull fracture.  Fracture-a-la-signature derives its name from forensic medicine because the size and shape of a depressed skull fracture may give information on the type of weapon used. It can be a si...
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Fracture types (summary)

This is a basic article for medical students and other non-radiologists Determining fracture type is really important when looking at a fracture and trying to describe it. Fractures can broadly be split into complete and incomplete fractures. Reference article This is a summary article. For m...
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Fragile X-associated tremor/ataxia syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive degenerative movement disorder resulting from a fragile X “premutation”, defined as 55-200 CGG repeats in the 5’-untranslated region of the FMR1 gene 1. The premutation can expand in subsequent generations (during oogenesis) to...
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Free-floating thrombus of the internal carotid artery

Free-floating thrombus of the internal carotid artery is an uncommon entity placing the patient at high risk for acute ischemic stroke. It is characterised by intraluminal thrombus within the internal carotid artery (ICA) and aggressively managed with surgical, medical, or combined therapy.  Ep...
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Friedreich ataxia

Friedreich ataxia (FA) is the most common inherited progressive ataxia. It carries an autosomal recessive inheritance 1. Epidemiology Thought to have an estimated prevalence of ~1:50,000. There is no recognised gender predilection. Typically present in childhood to adolescence. Those with a h...
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Frontal horn width to intercaudate distance ratio

Frontal horn width to intercaudate distance ratio (FH/CC) is used in assessing patients with suspected Huntington's disease.  On the same axial plane obtained on the ACPC (anterior commissure and posterior commissure) line, the ratio between the distance between the caudate heads (where they ar...
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Frontal lobe

The frontal lobe is by far the largest of the four lobes of the cerebrum, and is responsible for many of the functions which produce voluntary and purposeful action.  Gross anatomy The frontal lobe is the largest lobe accounting for 41% of the total neocortical volume 8. The frontal lobe resid...
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Frontal pole

The frontal pole is one of the three poles of the brain (along with the occipital pole and temporal pole), and corresponds to the anterior most rounded point of the frontal lobe. It does not have easily defined boundaries, but is roughly equivalent to the frontopolar cortex, which in turn is co...
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Frontal sinus outflow tract

The frontal sinus outflow tract is the drainage pathway of the frontal sinus. It is an hourglass-shaped structure with its waist at the frontal ostium. Terminology Depending on the references, the term frontal sinus outflow tract is either used synonymously with frontal recess or it can ref...
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Frontoethmoidal encephalocele

Frontoethmoidal encephaloceles are second only to occipital encephaloceles in terms of frequency, representing approximately 15% of all encephaloceles. They represent meninges or brain tissue herniating through a cranial defect in the anterior cranial fossa and typically result in facial deformi...
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Frontolacrimal suture

The frontolacimal suture is the cranial suture between the frontal and lacrimal bones.
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Frontonasal dysplasia

Frontonasal dysplasia, also known as median cleft face syndrome, is a rare disorder characterised by midline defects involving the face, head, and central nervous system. Epidemiology Frontonasal dysplasia is considered to be a very rare condition, with approximately 100 cases having been repo...
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Frontopolar artery

The frontopolar artery is a branch of the A2 segment of the anterior cerebral artery (ACA), commonly arising after the medial frontobasal artery and coursing obliquely across the medial surface of the cerebral hemisphere towards the frontal pole.
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Frontopolar cortex

The frontopolar cortex is located at the frontal pole of each frontal lobe, and is comprised of three roughly horizontal gyri: superior, middle and inferior frontopolar gyri.  It contains Brodmann area 10, which is thought to contribute to many aspects of cognition 1,2. Despite many studies re...
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Frontotemporal dementia

Frontotemporal dementia (FTD) is a confusing term used inconsistently in the literature and is thus best avoided. The following are some of the conditions sometimes denoted by this term: frontotemporal lobar degeneration (FTLD) 1 behavioural variant of FTLD 2 Pick disease (an anti...
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Frontotemporal lobar degeneration

Frontotemporal lobar degeneration (FTLD) is the pathological description of a group of neurodegenerative disorders characterised by focal atrophy of the frontal and temporal cortices. The conditions grouped under this term vary from publication to publication, depending on whether clinical, path...
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Fukuyama congenital muscular dystrophy

Fukuyama congenital muscular dystrophy (FCMD) is a form of congenital muscular dystrophy. Epidemiology FCMD is almost exclusively found in Japan where it has an incidence of 2-4 per 100,000 infants and is the second most common muscular dystrophy after Duchenne muscular dystrophy 1,2. However,...
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Functional MRI

Functional magnetic resonance imaging (fMRI) is a technique used to obtain functional information by visualising cortical activity. fMRI detects subtle alteration in blood flow in response to stimuli or actions. It is used in two broad ways: clinical practice typically in pre-surgical patients...
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Fusiform gyrus

The fusiform gyrus, also known as the temporo-occipital gyrus is a structure that lies on the basal surface of the temporal and occipital lobes. It forms part of Brodmann area 37, along with the inferior and medial temporal gyri. As its name suggests, it is composed of a temporal or anterior por...
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Fusiform intracranial aneurysm

Fusiform intracranial aneurysms are a type of intracranial aneurysms with an elongated fusiform shape caused by atherosclerotic disease most common in the vertebrobasilar circulation. Epidemiology 3%-13% of all intracranial aneurysms Clinical presentation They can be incidental or asymptomat...
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Galassi classification of middle cranial fossa arachnoid cysts

The Galassi classification of middle cranial fossa arachnoid cysts is used to classify arachnoid cysts in the middle cranial fossa, which account for 50-60% of all arachnoid cysts 1. Galassi et al. published this classification in 1982, and at the time of writing (June 2016), it remains the most...
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Gamma-aminobutyric acid (GABA) peak

Gamma-aminobutyric acid (GABA) is the principle inhibitory neurotransmitter in the central nervous system 1 and as such, is one of the compounds examined in MR spectroscopy.  It is present in the human brain at a concentration of about 1 mM, a whole order of magnitude lower than some of the more...
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Gangliocytoma

Gangliocytomas are rare indolent CNS tumours (WHO grade I), primarily encountered in children, and frequently discovered as the cause of epilepsy. They differ from gangliogliomas by the absence of neoplastic glial cells, although both tumours are defined by the presence of displaced ganglion cel...
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Ganglioneurocytoma

Ganglioneurocytomas are rare variants of extraventricular neurocytomas, themselves an uncommon variant of central neurocytomas (intraventricular). They are recognised in the current (2016) WHO classification of CNS tumours when an extraventricular neurocytoma demonstrates a distinctive and defi...
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Ganglioneuroma

Ganglioneuromas are fully differentiated neuronal tumours that do not contain immature elements and potentially occur anywhere along the peripheral autonomic ganglion sites.  On imaging, usually, they present as well-defined solid masses and can be quite large at presentation. Generally, they a...
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Gasperini syndrome

Gasperini syndrome is a rare pontine stroke syndrome that involves the caudal pons tegmentum. Clinical presentation Classically, the syndrome presents with 1-3: involvement of the CN V nucleus: ipsilateral facial sensory loss involvement of the CN VI nucleus: ipsilateral impaired eye abducti...
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Gemistocytic astrocytoma

Gemistocytic astrocytoma is a histologic subtype of low grade astrocytoma, with a poorer prognosis than other matched WHO grade tumours, and with no specific imaging features.  For a general discussion of clinical presentation, epidemiology, treatment please refer to the article on low grade as...
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Geniculate ganglion

The geniculate ganglion contains fibres for taste and somatic sensation and is located in the petrous temporal bone.  Gross anatomy It is located at the first genu of the facial nerve at the anterior most part of the Fallopian canal at the junction between the labyrinthine and tympanic segment...
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Germinal matrix haemorrhage

Germinal matrix haemorrhages, also know as periventricular-intraventricular haemorrhages (PVIH), correspond to the most common type of intracranial haemorrhage in neonates and are related to a perinatal stress affecting the highly vascularised subependymal germinal matrix. The majority of cases ...
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Germinoma

Germinoma is a term that if unqualified, usually refers to a tumour of the brain but can also refer to similar tumours of other regions particularly the ovary and testis. dysgerminoma of the ovary seminoma of the testis CNS germinoma: see WHO classification of CNS tumours All these tumours s...
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Gerstmann-Straussler-Scheinker disease

Gerstmann-Straussler-Scheinker disease is a very rare type of human transmissible spongiform encephalopathy. It manifests with dementia and/or ataxia and is due to a mutation in the prion protein (PRNP) gene, which is inherited in an autosomal dominant pattern.  History and etymology It is par...
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Gerstmann syndrome

Gerstmann syndrome, also known as angular gyrus syndrome, is a dominant hemisphere stroke syndrome consisting of four components:  agraphia or dysgraphia acalculia or dyscalculia finger agnosia left-right disorientation Pure Gerstmann syndrome is said to be without aphasia. History and ety...
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Giant cell glioblastoma

Giant cell glioblastoma is a variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) recognised in the current (2016) WHO classification of CNS tumours 7. This tumour was previously called monstrocellular tumour due to the macro size of its cells. Epidemiology ...
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Giant cerebral aneurysm

Giant cerebral aneurysms are ones that measure >25 mm in greatest dimension.  Epidemiology Giant cerebral aneurysms account for ~5% of all intracranial aneurysms 1,3. They occur in the 5th-7th decades and are more common in females 2. Clinical presentation Patients can present with symptoms ...
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Gigantism

Gigantism is a nonspecific term that refers to enlargement of normal body proportions and can be divided into generalised gigantism (i.e. of the whole body) or localised gigantism (i.e. affection only part of the body).  Localised gigantism is due to a variety of causes, and is discussed separa...
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Ginkgo leaf sign (spinal meningioma)

The ginkgo leaf sign of spinal meningiomas (not to be confused with the ginkgo leaf sign of subcutaneous emphysema) has been described as a useful MRI sign in distinguishing a spinal meningioma from neurogenic tumour (e.g. spinal schwannoma).  It is seen on axial post contrast T1 imaging, with ...
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Glasgow Coma Scale

The Glasgow Coma Scale (GCS) was developed in 1974 1 to describe the level of consciousness specifically in patients with head injury although it is now used widely as a shorthand for all manner of presentations and has generally been validated, although concerns remain about its use in certain ...
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Glial cells

Glial cells, or neuroglia, are cells that surround the neurones of the central nervous system embedded between them, providing both structural and physiological support 1-3.  Together they account for almost half of the total mass 1 and 90% of all cells of the central nervous system 3. These num...
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Glial fibrillary acid protein (GFAP)

Glial fibrillary acid protein (GFAP) is a commonly used target for immunohistochemistry and is positive in many glial cells and tumours of glial origin. GFAP is the building block for intermediate filaments which are abundant in the cytoplasms particularly of astrocytes. 
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Glioblastoma

Glioblastoma (GBM) is the most common adult primary intracranial neoplasm (see brain tumours), accounting for 15% of all intracranial neoplasms and approximately 50% of all astrocytomas. GBMs are high grade astrocytomas; they are therefore generally aggressive, largely resistant to therapy, and ...
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Glioblastoma NOS

Glioblastoma NOS (not otherwise specified) is a diagnosis in the current (2016) WHO classification of CNS tumours and denotes a diffuse glioma with astrocytic features and anaplasia, microvascular proliferation and/or necrosis consistent with a WHO grade IV glioblastoma but with inconclusive or ...
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Glioblastoma vs cerebral metastasis

Differentiating a glioblastoma (GBM) from a cerebral metastasis is a frequent challenge, with profound surgical, workup and treatment implications. Unfortunately distinguishing between the two entities is not always straightforward.  This article addresses helpful imaging features to aid in dis...
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Gliomatosis cerebri

Gliomatosis cerebri is a rare growth pattern of diffuse gliomas that involves at least three lobes by definition. There often is an important discordance between clinical and radiological findings, as it may be clinically silent while it appears as a very extensive process radiologically. Impor...
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Glioma treatment response assessment in clinical trials

Glioma treatment response assessment in clinical trials has undergone numerous revisions with a number of criteria having been developed over the years. This has been necessary as a result of a number of factors: improved understanding of tumour biology (e.g. appreciating importance of non-enha...
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Gliosarcoma

Gliosarcomas are a variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) recognised in the current (2016) WHO classification of CNS tumours 9. They are highly malignant (WHO grade IV) primary intra-axial neoplasms with both glial and mesenchymal elements. Ter...
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Gliosis

Gliosis is the focal proliferation of glial cells in the CNS in response to insult. By strict definition, gliosis is not synonymous with encephalomalacia which is the end result of liquefactive necrosis of brain parenchyma following an insult. Radiologically they share similar features and the d...
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Global cortical atrophy scale

The global cortical atrophy (GCA) scale, also known as the Pasquier scale, is a qualitative rating system developed to assess cerebral atrophy, especially in the context of neurodegenerative diseases. It evaluates atrophy in 13 brain regions assessed separately in each hemisphere and resulting i...
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Globe

The globes or simply, the eyes are paired spherical sensory organs, located anteriorly on the face within the orbits, which house the visual apparatus. Gross anatomy Location The globe is suspended by the bulbar sheath in the anterior third of the bony orbit.  Size Each globe is an approxim...
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Globe rupture

Globe rupture is an ophthalmologic emergency. A ruptured globe or an open-globe injury must be assessed in any patient who has suffered orbital trauma because open-globe injuries are a major cause of blindness. In a blunt trauma, ruptures are most common at the insertions of the intraocular mus...
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Globus pallidus

The globus pallidus (plural: globus pallidi) is a paired structure and one of the nuclei that make up the basal ganglia. It is a subcortical structure at the base of the forebrain and in anatomical relation to the caudate nucleus and putamen. It forms the lentiform nucleus with the putamen. Eac...
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Glomus jugulotympanicum paraganglioma

Glomus jugulotympanicum paraganglioma is a glomus jugulare paraganglioma that has spread superiorly to involve the middle ear cavity. The term can also be used clinically when a suspected glomus tympanicum paraganglioma involves the hypotympanum as its inferior extent cannot be established clini...
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Glomus tympanicum paraganglioma

Glomus tympanicum paragangliomas (chemodectomas) are the most common middle ear tumour.  Epidemiology There is a female predominance (M:F = 1:3); presentation is most common when patients are more than 40 years old 1,2.  Clinical presentation May be incidental but symptomatic masses produce ...
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Glossopharyngeal nerve

The glossopharyngeal nerve is the ninth (IX) of the twelve pairs of cranial nerves. It exits the brainstem out from the sides of the upper medulla, just rostral to the vagus nerve and has sensory, motor, and autonomic components. Gross anatomy Origin The sensory ganglion cells lie in the supe...
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Glossopharyngeal neuralgia

Glossopharyngeal neuralgia is due to irritation of the glossopharyngeal nerve and presents with repeated episodes of severe pain in the tongue, throat, ear, and tonsils, which can last from a few seconds to a few minutes. It is far less common than trigeminal neuralgia. Epidemiology Glossophar...
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Glutamine-Glutamate peak

Glutamate-Glutamine (Glx) peak is one of the regions assessed on MR spectroscopy, and resonates between 2.2 and 2.4 ppm chemical shift. It overlaps with the GABA peak and cannot be routinely separated from each other.
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Glutaric aciduria type 1

Glutaric aciduria type 1 is a leukodystrophy that can be subclassified as an organic acidopathy. It has a highly variable clinical presentation, and laboratory investigations are not always diagnostic. Imaging, therefore, has an important role to play as the MRI features can be characteristic. ...
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Glymphatic pathway

The glymphatic pathway has only recently been described and functionally represents the brain’s lymphatic system, although no anatomical structure equivalent to the peripheral lymphatic system is present within the brain parenchyma. It is believed to be a crucial normal homeostatic feature allow...
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Gomez-Lopez-Hernandez syndrome

Gomez-Lopez-Hernandez syndrome, also known as cerebellotrigeminal-dermal dysplasia, is a rare phakomatosis characterised by rhombencephalosynapsis, parietal-occipital scalp alopecia, brachycephaly, facial malformations and trigeminal anesthesia.  History and etymology It is named after Manuel ...
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Gradenigo syndrome

Gradenigo syndrome consists of the triad of: petrous apicitis abducens nerve palsy, secondary to involvement of the nerve as it passes through Dorello canal retro-orbital pain, or pain in the cutaneous distribution of the frontal and maxillary divisions of the trigeminal nerve, due to extensi...
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Grading of brachial plexus injuries

According to CT myelography, brachial plexus injuries can be classified into six types 1: N type: normal root sleeve and nerve roots A1 type: slightly deformed root sleeves and nerve roots as compared to unaffected site A2 type: obliteration of the tip of root sleeves and deformed thickened n...
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Granular cell tumour of the pituitary region

Granular cell tumour of the pituitary region, also known as a pituitary choristoma, are rare low-grade tumours of the posterior pituitary and infundibulum.  Terminology Care must be taken when reading older literature as granular cell tumours of the pituitary region, and alternative names incl...
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Granulocytic sarcoma

Granulocytic sarcoma (also called myeloid sarcoma and chloroma) is a rare neoplasm comprised of myeloid precursor cells. Epidemiology It is typically seen is in children with ~60% occurring in individuals less than 15 years of age. There is no recognised gender predilection. Granulocytic sarc...
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Granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem systemic necrotising non-caseating granulomatous vasculitis affecting small to medium sized arteries, capillaries and veins, with a predilection for the respiratory system and kidneys 3. This ar...
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Granulomatosis with polyangiitis (CNS manifestations)

CNS manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener granulomatosis) are rare. Granulomatosis with polyangiitis is a multi-system systemic necrotizing non-caseating granulomatous vasculitis affecting small to medium-sized arteries, capillaries and veins. Epi...
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Granulomatous amoebic encephalitis

Granulomatous amoebic encephalitis (GAE), also referred to as cerebral amoebiasis, is a rare and usually fatal subacute-chronic CNS infection in immunocompromised patients caused by free-living amoebae such as Acanthamoeba spp (main cause), Balamuthia mandrillaris and Sappinia pedata. This is a...
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Greater palatine foramen

The greater palatine foramen is the opening in the posterior hard palate of the greater palatine canal, which is formed between the articulation of maxillary bone and the greater palatine sulcus of palatine bone. The canal is also known as the pterygopalatine canal. A small accessory canal branc...
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Greater superficial petrosal nerve

The greater (superficial) petrosal nerve originates at the geniculate ganglion, where the nervus intermedius and facial nerve join. It contains mainly preganglionic parasympathetic fibers and some sensory taste afferent from the soft palate. It arises at the geniculate ganglion, passes through ...
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Grey matter heterotopia

The grey matter heterotopias are a relatively common group of conditions characterised by interruption of normal neuronal migration from near the ventricle to the cortex, thus resulting in "normal neurons in abnormal locations" 2. They are a subset of disorders of cortical formation 3-4. Grey m...
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Grey-white differentiation

Grey-white differentiation refers to the appearance of the interface between cerebral and cerebellar white matter and grey matter on brain CT and MRI. The term is most often used when trying to differentiate cytotoxic from vasogenic oedema.  cytotoxic oedema (see ionic oedema), where there is ...
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Ground glass density nodule

A ground glass density nodule (GGN) is a circumscribed area of increased pulmonary attenuation with preservation of the bronchial and vascular margins. A GGN can be: partly solid (part of the ground-glass opacity completely obscures the parenchyma) non-solid (no completely obscured areas) - pu...
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Growing teratoma syndrome

Growing teratoma syndrome is a rare complication after treatment for metastatic (or in the case of intracranial disease, primary) non-seminomatous germ cell tumours (NSGCT). It was first described in the paediatric population with treated germ cell neoplasms, and represents enlarging masses at ...
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Gudden's commissure

Gudden’s commissure, also called the ventral supraoptic decussation, is one of three tracts that comprise the supraoptic commissure 1,2.  The remaining two tracts that comprise the supraoptic commissure are Meynert's commissure (dorsal supraoptic commissure) and the anterior hypothalamic commiss...
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Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is defined as a heterogeneous group of autoimmune polyradiculopathies, involving sensory, motor and autonomic nerves. It is the most common cause of rapidly progressive flaccid paralysis. It is believed to be one of a number of related conditions, sharing a similar ...
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Gyrus rectus

The gyrus rectus, or straight gyrus, is located at the medial most margin of the inferior surface of frontal lobe 1,2. Its function is unclear but it may be involved in higher cognitive function (e.g. personality) 3. Gross anatomy The gyrus rectus is bounded medially by the interhemispheric fi...
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Habenula

The habenula is part of the epithalamus and receives input from the brain via the stria medullaris. It outputs to many midbrain areas involved in releasing neuromodulators, such as dopamine, norepinephrine, and serotonin. The habenula was traditionally divided into lateral (limbic) and medial (...
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Habenular commissure

The habenular commissure is a white matter tract connecting the two habenular nuclei and the internal medullary laminae 1. Whilst the exact role of the habenular commissure is unknown, the habenular nuclei play an important role in influencing how the brain responds to a variety of stimuli, incl...
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Haemangioblastoma (central nervous system)

Haemangioblastomas are tumours of vascular origin and occur both sporadically and in patients with von Hippel Lindau (vHL). They are WHO grade I tumours that can occur in the central nervous system or elsewhere in the body, including kidneys, liver, and pancreas. These tumours generally present...
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Haematocrit effect

The haematocrit effect with fluid-fluid levels is the result by layering of heavier cellular elements of blood located dependent to a liquid supernatant. It can be seen on CT or MRI. It is most frequently seen in the setting of anticoagulation therapy or coagulopathy. See also signal flare phe...
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Haematomyelia

Haematomyelia refers to the presence of intramedullary haemorrhage or haematoma within the spinal cord. This is distinct from extramedullary haemorrhage such as that seen in epidural haematoma. Pathology Although haematomyelia can occur in the setting of trauma, the term is generally used to s...

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