Neurological Glossary

F-wave

Long latency muscle action potential seen after supramaximal stimulation to a nerve

Facial masking (hypomimia)

Decreased facial expression due to rigidity of facial muscles

Facial nerve (cranial nerve VII)

Predominantly motor nerve supplying muscles of facial expression; also carries sensation (external ear

Falx cerebri

Fold of dura mater in the sagittal sulcus between the two cerebral hemispheres

Familial hypercholesterolaemia (FH)

An inherited disorder characterised by a high level of serum cholesterol and early evidence of atherosclerosis (hardening of the arteries).

Fascicle

Bundle of axons (nerve fascicle) or muscle fibres (muscle fascicle) surrounded by a layer of contractile cells (perineurium for nerves or perimusium for muscles)

Fasciculation

Spontaneous firing of an axon resulting in a visible twitch of all the muscle fibers it contacts; indicative of denervation

FAST test

FES (Functional Electrical Stimulation)

The principle of FES is to replace the nerve impulses to the muscles

FFO

Functional Foot Orthosis

Festination

An involuntary tendency to take short accelerating steps in walking that can occur in Parkinson disease

Febrile seizure

Typically benign seizure associated with high fever in children aged 3 months to 5 years

Fibrillation

Spontaneous firing of a single muscle fibre not visible to the naked eye

Field of vision

The area that you can see without moving your eyes (or your head)

Filum terminale

Delicate fibrous tissue structure surrounded by a few nerve fibres that extends downward from the conus medullaris to the first segment of the coccyx

Finger agnosia

Type of agnosia characterized by inability to identify the fingers; a component of Gerstmann syndrome

Fisher scale

Scale for grading CT appearance in patients with nontraumatic subarachnoid hemorrhage; higher scores predictive of developing symptomatic cerebral vasospasm

Fibrinoid necrosis

Brightly eosinophilic lesions in the small vessels of the brain postulated to occur because of disordered cerebral autoregulation in association with aging and hypertension; contributes to the development of lacunar infarction and hypertensive haemorrhage

Flaccidity

Severe form of hypotonicity

Flexion

Bending

Flexor

The name given to those muscles which

Flexor plantar response

Flexion (curling down) of all toes ('downgoing toe') in response to application of a stimulus to the skin of the foot or leg; normal response

Flexor posturing

Stereotyped posture occurring in coma in response to stimulation in which the upper extremity flexes and the lower extremity extends; reflects release of primitive responses from the suppression of more rostral motor areas that have been damaged and is reminiscent of the decorticate state demonstrated in animals with transaction of corticospinal fibers above the midbrain

Flexor spasm

Often painful manifestation of spasticity in which the legs involuntarily pull upward into a clenched position for a period of a few seconds

Floccillation

Purposeless picking at clothing or bedding seen in delirium

Flocculus

Small lobe of the posterior cerebellum; comprises the lateral portion of the vestibulocerebellum

Fluent aphasia (Wernicke's or receptive aphasia)

Impairment of language comprehension including impaired repetition due to lesion of the posterior left superior temporal gyrus (Brodmann area 22)

Focal seizures

Epilepsy that occurs as a result of 'short circuiting' in the brain

Fontanel

Soft membranous gap between the incompletely formed cranial bones of a fetus or an infant; the anterior fontanel (where the metopic

Foramen magnum

Large opening at the base of the skull through which the spinal cord and vertebral arteries pass from the vertebral cavity into the cranial cavity

Foramen of Magendie

Midline exit of CSF from the fourth ventricle into the subarachnoid space

Foramen of Monro

Permits communication of the third ventricle with each of the lateral ventricles on anterolateral aspect of the third ventricle

Foramina of Luschka

Lateral exits of CSF from either side of the fourth ventricles into the subarachnoid space

Forebrain

Portion of the central nervous system derived from prosencephalon; commonly used to denote cerebral hemispheres and diencephalon

Fornix

White matter structure containing axons that connect the hippocampus to the hypothalamus and septal nuclei

Fortification spectrum (teichopsia)

Complex visual migraine aura consisting of zig-zag lines or an arc of scintillating lights forming into a herringbone pattern and expanding to encompass an increasing portion of a visual hemifield

Foster-Kennedy syndrome

Ipsilateral anosmia

Fovea

Centre most part of the macula responsible for detailed central vision

Foville syndrome

Ipsilateral lateral gaze palsy

Fracture-dislocation

Fracture through the articular processes and disc with or without associated fracture through a vertebral body due to flexion/extension with axial loading; unstable and often associated with spinal cord injury

Freezing

Sudden

Fresnel prisms

Clear

Fried egg artifact

perinuclear halo around oligodendrocytes caused by formalin fixation artifact

Friedreich's ataxia

autosomal recessive neurodegenerative disease caused by GAA triplet repeat mutation in the gene that encodes for frataxin

Frontal eye fields (FEF)

Region within the frontal lobes from which voluntary lateral eye movements originate; with stimulation (as in seizure)

Frontotemporal dementia

Group of dementing illnesses in which disordered behaviour .

Functional Magnetic Resonance Imaging (fMRI)

An advanced magnetic scanning technique using to generate images of changing blood flow in the brain associated with neural activity. Increasingly used in early diagnosis

Functional

Not due to organic disease