Neurological Glossary

Habenula

Diencephalic structure located on the dorsomedial surface of the caudal thalamus that receives afferents from the septal nuclei and hypothalamus via the stria medullaris and projects to midbrain nuclei; involved in autonomic processing

Haematoma

A blood clot that has formed outside a blood vessel (artery or vein)

Haemorrhage

The escape of blood from a ruptured blood vessel

Haemorrhagic infarct

An area of dead brain that has had bleeding in it

Haemorrhagic stroke

A stroke caused by a burst blood vessel bleeding into the brain (intracerebral haemorrhage) or into the surrounding areas (subarachnoid haemorrhage)

HDL-C (High-Density Lipoprotein Cholesterol)

Also known as the

HAFO

Hinged Ankle Foot Orthosis

Hangman's fracture

Fracture through bilateral pedicles of C2 via various mechanisms; typically unstable

Hemianesthesia

Loss of somatosensation on one half of the body

Hemianopia

Loss of vision in one half of the visual field

Hemiballismus

Involuntary violent flinging or jerking of a limb (or limbs) in an uncoordinated manner caused by a lesion of the contralateral subthalamus in the brain

Hemicrania continua

Indomethacin-responsive headache disorder characterised by steady

Hemifacial spasm

Segmental myoclonus of muscles innervated by the facial nerve; may be due to vascular compression of the facial nerve or facial nerve injury or tumour

Hemifield

One-half of the binocular visual field

Hemiparesis

Weakness on one side of the body

Hemiplegia

Paralysis on one side of the body

Hemiplegic migraine

Familial form of migraine characterized by temporary (usually less than 1 hour but occasionally lasting up to a week) hemisensory symptoms often associated with visual aura and headache; in about 50% of affected families

Heterotopia

Tissue occurring in an abnormal anatomical position

Hindbrain

Medulla

Hip dislocation

In children with spasticity the thigh bone [femur] can gradually be pulled out of its socket where it connects with the hip ' this is treated surgically

Hippocampal formation

Cortical structure in the medial temporal lobe comprising the dentate gyrus

Hippocampus

Convoluted structure at the medial margin of the cortical mantle of the cerebral hemisphere

Hoffman's sign

Contraction of fingers and thumb when a stimulus is applied to a distal phalanx in that hand; indication of hyperreflexia in the upper extremity

Holoprosencephaly

Failure of cleavage at the rostral end of the notochord resulting in midline fusion of the frontal lobes

Homer-Wright rosette

Halo of cells surrounding a central lumen containing neuropil; found in medulloblastomas and PNETs

Horner's syndrome

Ptosis

H-reflex

Electrical equivalent of the monosynaptic stretch reflex elicited by selectively stimulating the fibres of the posterior tibial or median nerve

Hunt and Hess scale

Scale for grading clinical status in patients with nontraumatic subarachnoid hemorrhage that correlates well with clinical outcome Click here for more information from the Stroke Trials Registry

Huntington disease

Fatal autosomal dominant neurodegenerative disorder characterized by chorea and progressive dementia; due to a trinucleotide CAG-repeat mutation on chromosome 4

Hydranencephaly

Birth defect in which the majority of the cerebral hemispheres and striatum are absent and replaced by sacs filled with cerebrospinal fluid; considered to be an extreme form of porencephaly

Hydrocephalus

Meaning

Hyperacusis

Abnormally increased sensitivity to sound

Hyperbaric Oxygen Therapy

Oxygen therapy used in the treatment of a variety of conditions

Hyperkinesis

Incessant

Hyperpathia

Exaggerated response to painful stimuli

Hypersomnolence

see excessive daytime sleepiness

Hypertensive hemorrhage

Intraparenchymal hemorrhage with a predilection to occur deep in the cerebral hemispheres

Hypertonia

Too much muscle tone leading to stiffness

Hypertonicity

Increase in passive muscle resistance

Hypertropia

An eye with strabismus that deviates up

Hypnagogic hallucination

Vivid dreamlike hallucination that occurs as one is falling asleep; one of the symptoms of narcolepsy

Hypnic headache

Indomethacin-responsive headache disorder characterized by diffuse

Hypnic

Jerk sensation of falling

Hypnopompic hallucination

Vivid dreamlike hallucination that occurs as one is waking up; one of the symptoms of narcolepsy

Hypoglossal nerve (cranial nerve XII)

Motor nerve that innervates all tongue muscles except the palatoglossus; lesions result in deviation of the protruded tongue towards the paralyzed side and deviation of the tongue at rest away from the paralyzed side; nucleus is located in the medulla

Hypothalamus

Basal part of the diencephalon that controls hunger

Hypotonia

Too little muscle tone leading to floppiness

Hypotonicity

Reduction in passive muscle resistance

Hypotropia

An eye with strabismus that deviates down

Hypoxia

Reduction in the supply of oxygen to the brain or other vital organ