Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

Glossary of Common Neurologic Terms by mikesanye


									        Glossary of Common
        Neurologic Terms

Accommodation Sensory nerves having dynamic          Anal reflex Reflexive contraction of anal sphinc-
   firing rates that decline with time even though      ter upon perianal sensory stimulation.
   the stimulus is maintained. Changes in the eye    Aneurysm Abnormal dilatation or bulging of an
   that enable clear vision at various distances.      intracranial artery wall, usually at bifurcations
Afferent pathway Axons leading to the brain or         of the Circle of Willis.
   spinal cord.                                      Anisocoria Unequal pupil size.
Agnosia Lack of knowledge and is synonymous
                                                     Ankle jerk Deep tendon reflex (Achilles reflex)
   with an impairment of recognition. An exam-
                                                       elicited by striking the Achilles tendon at the
   ple is visual agnosia in which patient cannot
                                                       ankle resulting in foot plantar flexion.
   arrive at the meaning of previously known
   nonverbal visual stimuli despite normal visual    Anterior horn Gray matter in the ventral spinal
   perception and alertness.                           cord that contains neurons including anterior
                                                       horn cells (lower motor neurons).
Agraphia Inability to recognize numbers/letters
   written on the palm or fingertips.                 Anterior root Segment of motor nerves com-
Alexia Acquired reading impairment that may            posed of anterior horn neurons exiting the ven-
   be accompanied with writing deficits (alexia         tral spinal cord to where they join the mixed
   with agraphia) or without writing deficits          peripheral nerve.
   (alexia without agraphia).                        Anton’s syndrome Lesions involving the occipi-
Allodynia Non-painful cutaneous stimuli caus-          tal and parietal lobes that produce blindness or
   ing pain.                                           a homonymous hemianopia that is denied by
                                                       the patient.
Amaurosis fugax Transient monocular blind-
   ness. This usually comes from an internal         Aphasia Disorder of expression or comprehen-
   carotid artery embolus temporarily occluding        sion of spoken language due to dysfunction of
   the ophthalmic artery.                              language centers in dominant cerebral cortex or
Amnesia Partial or complete loss of the ability to     thalamus.
   learn new information or to retrieve previously   Apoptosis Genetically programmed neuronal
   acquired knowledge.                                 cell death that may be normal or abnormal.
Amyotrophy Wasting of muscles usually from           Apraxia Inability to perform a learned act,
   denervation.                                        despite demonstrated ability to perform com-



   ponents of the act usually due to dysfunction       Bruit Sound due to turbulence of blood passing
   of a parietal lobe.                                   a narrow artery segment, often heard from the
Arteriovenous malformation (AVM) Abnormal                internal carotid artery in the neck.
  blood vessel complex consisting of arteries,         Bulbar Refers to the medulla and pons of the
  veins, and capillaries located in the brain or         lower brainstem.
  spinal cord that often hemorrhage.                   Calcarine cortex Primary visual cortex located
Arteritis Inflammation of walls of arteries.              in the medial occipital lobe.
Astereognosis The inability to distinguish and         Caloric test Placement of warm or cool water in
                                                         the external canal to evaluate eye movements
   recognize small objects based on size, shape,
                                                         from stimulation of the vestibulo-ocular reflex.
   and texture when placed in the hand that has
   normal primary tactile sensory input.               Cauda equina Lumbosacral nerve roots in the
                                                         lumbar and sacral vertebral canal before the
Ataxia Incoordination of limb or body move-
                                                         exit via neural foramina.
   ments, particularly gait, often due to impair-
                                                       Caudal Lower in the neural axis compared with
   ment of cerebellar function.
                                                         other structures of the same kind nearer the
Athetosis Involuntary movements characterized            head.
  by slow, sinuous, twisting of arms, legs, or body.
                                                       Charcot-Marie-Tooth disease Dominant auto-
Atrophy Wasting of muscle/s from disuse or               somal genetic disease affecting distal myeli-
   denervation.                                          nated axons of limbs, especially legs producing
Autism Childhood illness affecting language and          distally symmetrical polyneuropathy.
  interpersonal relationships.                         Cheyne-Stokes respirations Regular cyclic oscil-
Babinski sign Extensor response of the great toe         lations of breathing between hyperpnea or over
  with fanning of the other toes in response to          breathing and apnea.
  stimulus on sole of foot. The extensor plantar       Chorea Abnormal involuntary movements
  response is normal in infants to about 9               characterized by rapid flicks or jerks of limb,
  months, thereafter reflects damage to the corti-        face, or trunk muscles.
  cospinal tract (upper motor neuron sign).            Chromatolysis Disintegration of chromophilic
Basal ganglia Deep gray matter nuclei of the             substance or Nissl body from neuron when the
  cerebral hemispheres comprising putamen,               axon is divided.
  caudate, globus pallidus, subthalamic nucleus,       Cogwheel rigidity Ratchet-like increased resist-
  substantial nigra, and often thalamus.                 ance to passive movement (hypertonia) usually
                                                         found at the wrists of patients with Parkinson’s
Biceps reflex Deep tendon reflex elicited by hit-
   ting the biceps tendon resulting in brief con-
   traction of the biceps muscle.                      Computerized tomography (CT) Neuroimag-
                                                         ing technique based on computer processing of
Brachioradialis reflex Deep tendon reflex                data from differential attenuation of x-ray
  elicited by hitting the distal radius resulting in     beam passing through tissue (often the skull &
  brief contraction of the brachioradialis muscle.       brain) that produces a series of slices through
Bradykinesia or Akinesia Difficulty in moving             the tissue.
  despite intact motor nerves and normal mus-          Constructional apraxia Disturbances in organ-
  cles as seen in Parkinson’s disease.                   izing parts of a complex object.
Broca’s aphasia Motor speech disorder (expres-         Corticobulbar tract Descending cortical motor
  sive aphasia, nonfluent or anterior aphasia) due        tract traveling to a brainstem motor nucleus.
  to dysfunction located in the dominant frontal       Corticospinal tract Descending cortical motor
  lobe and characterized by effortful, sparse,           tract primarily from motor cortex that
  agrammatic, halting, truncated speech with loss        descends down the spinal cord to synapse at
  of normal language melody.                             anterior horn cells or adjacent interneurons.

                                                  GLOSSARY OF COMMON NEUROLOGIC TERMS                 221

Countercoup Injury to brain on opposite side as       Dressing apraxia Lesions only involving the
  head trauma.                                          non-dominant parietal lobe that produce neg-
Coup Injury occurring to brain on same side as          lect on one side of the body in dressing and
  head trauma.                                          grooming.
Decerebrate posture Both arms and legs are            Dysarthria Impaired articulation of speech that
  extended, especially when painful stimuli are         sounds like “speaking with rocks in your
  administered usually due to a lesion that sepa-       mouth.”
  rates upper from lower brainstem.                   Dyskinesia Several involuntary movements of
Decorticate posture Flexion of one or both              limbs or face that include chorea, athetosis, tics,
  arms and extension of ipsilateral or both legs        and dystonia.
  due to lesion that isolates brainstem from con-     Dysmetria Limb ataxia in directed movement
  tralateral or bilateral cortical influences.           that misses the target.
Deep tendon reflexes (DTR) Term used to               Dysphagia     Impairment of swallowing.
  describe a monosynaptic stretch reflex elicited
                                                      Dysphonia Difficulty in speaking, often with a
  by tapping a tendon with resulting muscle con-
                                                        low speech volume.
                                                      Dystonia Strong, sustained, and slow contrac-
Demyelination Primarily loss of the axon nerve
  sheath in the peripheral or central nervous sys-      tions of muscle groups that cause twisting or
  tem with relative sparing of the underlying           writhing of a limb or the entire body. The con-
  axon. Segmental demyelination implies that            tractions are often painful and may appear dis-
  the myelin loss is patchy along the nerve leaving     figuring. The dystonia lasts seconds to minutes
  part of the axon with intact myelin.                  and occasionally hours producing a dystonic
Dizziness General term to describe sensation of
  light-headedness or feeling off balance.            Edema Excess water in the brain from swelling
                                                        of cell bodies (cytotoxic) or increased fluid in
Doll’s eyes maneuver Vestibulo-ocular reflex
                                                        extracellular spaces (vasogenic).
  that is performed usually in comatose patient
  where the head is rotated laterally but the eyes    Efferent pathway Axons leading away from the
  remain stationary and do not move with head.           brain or spinal cord.
Dominance Term that refers to cerebral hemi-          Electroencephalograph Instrument for record-
  sphere that controls language and principle            ing minute electrical currents developed in the
  limb involved in writing, eating, and throwing.        brain by means of electrodes attached to the
Dorsal column nuclei Nucleus gracilis and                scalp.
  cuneatus in the caudal medulla that contain 2nd     Electronystagmograph Instrument for record-
  order neuronal cell bodies for the dorsal              ing electrical signals generated by eye move-
  columns in the spinal cord and usually conduct         ments or nystagmus during tests to evaluate
  position sense, vibration, and touch sensations.       patients with vertigo.
Dorsal horn Dorsal (posterior) aspect of the          Epilepsy Illness resulting from repetitive
  spinal cord gray matter that contains neurons         seizures due to abnormal brain electrical activ-
  associated with peripheral afferent sensory           ity that is often subdivided into specific seizure
  fibers.                                                types (e.g., generalized tonic-clonic).
Dorsal root Part of the peripheral afferent sen-      Epley maneuver In patients with benign parox-
  sory nerve between the dorsal root ganglia and        ysmal positional vertigo, a variation of the
  the dorsal horn of the spinal cord.                   Hallpike maneuver is performed to roll loose
Dorsal root ganglia Cluster of 1st order periph-        otoconia around the posterior semicircular
  eral afferent sensory neuron cell bodies located      canal eliminating the recurrent brief vertigo
  at each segmental level near vertebral bodies.        spells.


Extraocular movements Eye movements due to              muscles places his hands on the knees and
  contraction of extraocular eye muscles rather         climbs up his thighs to stand.
  than muscles that govern the iris and lens.        Grasp reflex Involuntary grasping of the hand
Falx cerebri Rigid dural fold in midsagittal           when the palm is stimulated. This is normal in
   plane that separates the two hemispheres.           babies but abnormal in older children and
                                                       adults and is often associated with diffuse
Fasciculation Contraction of fascicle (group) of
                                                       frontal lobe damage.
   muscle fibers innervated by single nerve from
   one anterior horn neuron that produces visible    Gray matter Term that refers to gray color of
   intermittent spontaneous twitching of part of a     part of CNS that contains neurons rather than
   muscle but does not move the body part.             white matter that contains mainly axons and
                                                       myelin sheaths.
Fibrillation Spontaneous contraction (invisible
                                                     Hallpike maneuver A test to detect positional
   to the eye but detected by EMG) of individual
                                                       nystagmus performed by laying a patient down
   denervated muscle fibers no longer under the
                                                       with their head hanging below the table.
   control of a motor nerve.
                                                     Hammer toes Cocking up of toes like gun ham-
Flaccid   Limp muscle that has no muscle tone.
                                                       mers often due to a distal sensorimotor
Foramen magnum Large opening at base of                polyneuropathy causing atrophy and weakness
  skull where spinal cord and brainstem join.          of intrinsic flexor toe muscles with overriding
Fovea Central part of macula of retina related to      pull of more proximal extensor toe muscles.
  sharpest vision for reading.                       Hemianopia Refers to loss of vision in half the
Frenzel glasses Strong positive lenses that            visual field in the vertical plane. If both eyes are
   inhibit patients from seeing clearly enough to      equally involved, it is called homonymous
   fixate but allow the examiner to see the eye.        hemianopia.
   Glasses used to detect nystagmus.                 Hemiparesis Incomplete weakness involving
                                                       one side of body.
Gadolinium Rare earth compound given intra-
  venously before MRI to detect brain areas that     Horner’s syndrome Miosis, ptosis, and dimin-
  have a broken blood-brain barrier (such as at        ished sweating on the ipsilateral face due to
  tumors).                                             lesion in the 3rd neuron pathway starting in
                                                       hypothalamus and traveling to the brainstem,
Ganglia Clusters of neurons all having similar
                                                       thoracic spinal cord, cervical sympathetic gan-
  function, such as dorsal root ganglia.               glion, and sympathetic nerves along the carotid
Gerstmann’s syndrome The inability to desig-           and ophthalmic arteries.
  nate or name the different fingers of the two       Hydrocephalus Abnormal enlargement of one
  hands, confusion of the right and left sides of      or more ventricles of the brain. Obstructive
  the body and inability to calculate or to write.     hydrocephalus is when there is obstruction of
Glasgow coma scale Simple scoring system of            CSF flow in ventricular system or subarachnoid
  unconscious patients based on eye opening,           space. Hydrocephalus ex vacuo refers to passive
  motor response, and verbal response that is          ventricular enlargement from loss of surround-
  useful for prognosis.                                ing white matter and neurons. Communicating
                                                       hydrocephalus refers to nonobstructed pathway
Glia Term for supporting cells of CNS that
                                                       from spinal subarachnoid space to lateral ven-
   includes astrocytes and oligodendroglia.
Glioma Term used for CNS tumors of astrocyte
                                                     Hypertonia Increased muscle tone or resistance
   or oligodendrocyte lineage.                         produced by passive movement of a limb on a
Global aphasia Acquired loss of ability to com-        joint.
  prehend or produce verbal messages.                Hypotonia Decreased muscle tone or resistance
Gower’s maneuver Seen in muscular dystrophy            produced by passive movement of a limb on a
  where an individual with weak proximal leg           joint.

                                                   GLOSSARY OF COMMON NEUROLOGIC TERMS                223

Hypsarrhythmia Random, high-voltage slow               Lordosis Curvature of the spinal column with a
  waves and spikes seen on EEG that vary from in         forward convexity.
  time and location.                                   Lower motor neuron Motor neurons in the
Ice water caloric Test used in comatose patients         anterior horn of the spinal cord or brainstem
   to determine whether the pathway from the             that directly innervate muscles.
   vestibular inner ear to the 3rd and 6th cranial     Lumbar puncture Placement of a hollow needle
   nerves is intact. When pathway is intact, ice         with a stylet into the spinal canal in the lower
   water irrigated in one ear produces bilateral eye     lumbar space to withdraw cerebrospinal fluid
   movement to the ipsilateral side.                     or instill medications.
Infantile spasms Brief, symmetric contractions         Magnetic resonance imaging (MRI) Use of
   of neck, trunk, and limb muscles seen in infants      changing magnetic fields to create brain images
   (also called salaam seizures).                        as brain slices in any plane.
Ischemic penumbra Area of brain around an              Meralgia paresthica Sensory impairment and
   acute stroke that immediately has insufficient         dysthesias in the skin distribution of the lateral
   blood flow to function but sufficient to prevent        femoral cutaneous nerve of the thigh.
   cell death and may or may not subsequently
                                                       Mesial temporal sclerosis Progressive loss of
                                                         neurons and gliosis in one hippocampus that
Jaw jerk Corticobulbar reflex produced by tap-            often causes complex partial seizures.
   ping downward on the chin with resulting con-
                                                       Miosis   Abnormal constriction of a pupil.
   traction of masseter muscles and upward jaw
   movement. When unusually brisk, the jaw jerk        Mononeuropathy Lesion involving a single
   implies an upper motor neuron abnormality in          peripheral nerve.
   corticobulbar tract to 5th cranial nerve nuclei.    Mononeuropathy multiplex Lesions involving
Kernicterus Deposition of bile pigment in deep           more than one peripheral nerve.
  brain nuclei with neuronal degeneration from         Myalgia Muscle aches and pains that are not
  neonatal jaundice.                                     cramps.
Knee jerk (KJ) The patellar reflex is a deep ten-       Myelin Lipid-protein sheath that wraps some
  don reflex in which the patellar tendon is              peripheral nerves that is made by Schwann cells
  tapped causing a brief extension of the leg.           and some central nerves that is made by oligo-
Korsakoff ’s syndrome or psychosis Loss of               dendroglia.
  the ability to learn new memories with a ten-        Myeloradiculopathy Disease process affecting
  dency to fabricate answers. It is usually part of      the spinal cord, adjacent peripheral nerve roots,
  Wernicke-Korsakoff ’s encephalopathy from              and nerves.
                                                       Myoclonus Rapid, brief muscle jerks involving
Lateral geniculate body (nucleus) Thalamic               specific muscles or the entire body that do not
  nucleus that receives input from optic nerves          blend together and are shorter duration than
  and sends outward optic radiations to the              chorea. Nocturnal myoclonus is the normal
  occipital cortex and upper brainstem.                  abrupt body jerks that occur when an individ-
Lateral medullary syndrome Infarction of dor-            ual is falling asleep. The electroencephalogram
   solateral medulla and inferior cerebellum due         may or may not have spikes correlating with the
   to occlusion of posterior inferior cerebellar         myoclonus.
   artery, a branch of the vertebral artery.           Myopathy General term implying disease of
Lenticular (lentiform) nucleus Combination of            muscle from any cause.
  the putamen and the globus pallidus.                 Myotonia Abnormal sustained muscle contrac-
Leukomalacia Abnormal softening of white                 tions with slow relaxation that have a character-
  matter areas.                                          istic pattern on electromyogram.


Neglect Inability to attend normally to a portion    Paroxysmal Sudden event, as in spikes on elec-
  of extrapersonal or intrapersonal space or both      troencephalogram.
  that cannot be explained by altered perception.    Past pointing Repeated missing a target by
  In visual neglect, the patient ignores objects,      going too far or off to one side when using a
  persons, or movement in the left or right of the     finger or toe with closed eyes that is due to dys-
                                                       function of the vestibular system or cerebellum.
Neuraxis Longitudinal axis of the central nerv-
                                                     Patellar reflex Knee jerk reflex is a deep tendon
  ous system that runs from the rostral forebrain
                                                        reflex in which the patellar tendon is tapped
  to the caudal spinal cord.
                                                        causing a brief extension of the leg.
Neuronophagia Destruction of neurons by
                                                     Peripheral nervous system (PNS) All neural
  phagocytic cells.
                                                        structures that lie outside the spinal cord and
Neuropathy Term that describes disorders of             brainstem and includes motor, sensory, and
  peripheral nerves.                                    autonomic nerves and their ganglia.
Nocioceptive Sensory receptors that respond to
                                                     PERRLA Abbreviation for pupils equal, round,
  painful stimuli.
                                                       and reactive to light and accommodation.
Non-convulsive status epilepticus Complex
                                                     Phlebitis   Inflammation of veins.
  partial status epilepticus where the patient has
  constant confusion and impaired awareness but      Phonophobia Discomfort from noises that nor-
  can move his limbs.                                  mally do not cause discomfort.
Nystagmus Oscillatory eye movements that may         Photophobia Abnormal eye pain from bright
  be physiologic (following spinning in a circle)      lights.
  or abnormal (from inner ear, brainstem, and        Polyneuropathy Diffuse and symmetrical distal
  cerebellar dysfunction).                             dysfunction of sensory, motor, and autonomic
OD Right eye.                                          nerve axons that usually begins in the feet.
Ophthalmoplegia     Paralysis of eye movements.      Positron emission tomography (PET) Imaging
Oriented x 3 Oriented to person, place, and time       technique that detects emissions from injected
  in mental status testing.                            radiolabeled compounds to create a quantifi-
Orthostatic hypotension Fall in blood pressure         able image of blood flow, glucose utilization, or
  upon standing causing dizziness or even syn-         location of specific ligands that attach to brain
  cope.                                                receptors, etc.
OS Left eye.                                         Prefrontal lobe Part of brain anterior to the
                                                        motor and premotor cortex that is a multisen-
Otoconia Tiny calcium carbonate crystals
                                                        sory association cortex.
  embedded in a gelatinous matrix above the
  macula of the utricle and saccule that move        Prion Abnormal protein configuration of a nor-
  with gravity changes bending attached hair cells      mal host protein that causes transmissible
  allowing detection of gravity.                        spongiform encephalopathies, like Creutzfeldt-
Otorrhea CSF drainage from ear.                         Jakob disease.
Papilledema Swelling of optic nerve disc from        Proprioception Sense of position of body part
  elevated intracranial pressure.                      relative to fixed object like a floor that is both
                                                       unconscious and conscious.
Paraphasias Mispronounced or inappropriately
  substituted words with sematic paraphasias         Prosopagnosia Inability to recognize familiar
  being errors based on meanings of words (aunt        faces (facial agnosia).
  for uncle) and literal paraphasias being errors    Pseudobulbar palsy Syndrome that affects
  based on sounds (hook for took).                     speech articulation, phonation, swallowing,
Paresthesias Spontaneous firing of peripheral          and emotional lability due to bilateral dysfunc-
   nerve fibers causing a tingling sensation.           tion of corticobulbar tracts in the brainstem.

                                                     GLOSSARY OF COMMON NEUROLOGIC TERMS               225

Psychomotor retardation Abnormal slowing of              Salaam seizures Brief, symmetric contractions
   mental behavior and limb movements that is               of neck, trunk, and limb muscles seen in infants
   not due to mental retardation.                           (also called infantile spasms).
Ptosis Abnormal drooping of one or both eye-             Saltatory conduction Nerve action potential
   lids.                                                    that moves down a myelinated nerve by jump-
Putamen Part of basal ganglia. The caudate and              ing from node of Ranvier to node of Ranvier,
  putamen form the striatum and putamen and                 increasing conduction velocity to as fast as 80
  globus pallidus from the lentiform or lenticular          meters/second.
  nucleus.                                               Sciatica Term for radiating pain down a leg from
Quadrantanopia Loss of vision in one quadrant               damage to one or more lumbosacral nerve
  of vision.                                                roots that form the sciatic nerve.
Radiculopathy Damage to a nerve root leaving             Semicircular canals Three canals at right angles
  the spinal cord that causes weakness, sensory            to each other and located in the temporal bone
  loss or dysesthesias, and diminished reflex in            detect angular acceleration and serve to keep
  corresponding myotome and dermatome.                     eyes steady during head movement.
Ramsay Hunt syndrome Acute facial weakness               Shunt Tubing used to move cerebrospinal fluid
  due to herpes-zoster virus reactivation from the         that is blocked along its pathway (usually a ven-
  geniculate ganglion.                                     tricle) to the abdomen or jugular vein where it
Rigidity Constant resistance to muscle stretch-            can be absorbed.
   ing in both flexors and extensors throughout           Single photon emission computed tomography
   range of motion due to the stretching force              (SPECT) Imaging system that is similar but
   inducing some motor units to fire. In Parkin-             cheaper than positron emission tomography
   son’s disease, rapid flexion and extension of             that qualitatively determines regional blood
   wrist or elbow often elicits a ratchet-like feeling      flow or brain metabolism relative to other brain
   (cogwheel rigidity).                                     areas.
Rinne test Comparison of bone conduction                 Skew deviation of vision Vertical and slightly
  (placing a vibrating tuning fork on the mastoid          horizontal (diagonal) double vision that is the
  process) to air conduction in which air conduc-          same in all fields of gaze due to a brainstem
  tion normally is heard better.                           lesion.
Rolandic fissure Fissure that separates the              Snout reflex Pouting of lips following tapping
  motor cortex in the frontal lobe from the sen-           the lips.
  sory cortex in the parietal lobe.                      Spasticity Condition resulting from damage to
Romberg sign Ability to stand with feet together           the corticospinal tract in which at-rest muscles
  and eyes open and the inability to maintain              are in midposition and limbs held in a charac-
  posture with the eyes closed.                            teristic flexed posture. Rapid passive limb
Rooting reflex Normal turning of infant’s face              movement initially produces little resistance
  and lips toward a nipple touching the cheek but          but then quickly has increasing muscular resist-
  abnormal “frontal release reflex” when seen in            ance to a point when the resistance suddenly
  adults upon touching the cheek.                          disappears (“clasp-knife” phenomena).
Rostral Direction or position of neuroaxis               Stenosis Narrowing of lumen of artery or spinal
  towards the forebrain and away from the caudal            canal.
  spinal cord.                                           Strabismus Lack of eye alignment such that the
Saccadic eye movement Fast eye movement,                    two visual axes assume positions relative to
   voluntary or reflex, usually accomplishing               each other different from that required by the
   foveal fixation.                                          physiologic task.


Straight leg raise test Test for lumbar radicu-        Uncal herniation Movement of the uncal gyrus of
   lopathy in which passive elevation of a straight-      the medial temporal lobe under the tentorial
   ened leg produces pain in the lower back.              notch in response to mass in the temporal-frontal
Striate cortex Primary visual cortex.                     lobes producing increased intracranial pressure.
Striatum Combination of the caudate nucleus            Upper motor neuron Neurons in the upper
   and the putamen.                                       brain that synapse with lower motor neurons in
                                                          the brainstem or spinal cord.
Subfalcial space Space beneath the falx in which
   the cingulate gyrus can herniate from increased     Utricle Part of the inner ear that detects gravity.
   intracranial pressure.                              Valsalva maneuver Increase in intrapulmonic
Suck reflex Normal sucking response of infants             pressure by forcible expiration against a closed
   when touching the lips but abnormal “frontal-          glottis.
   release” reflex in adults when touching the lips     Ventricles Four cerebrospinal fluid-filled cavities
   elicits a sucking response.                            in the brain (lateral ventricles, third ventricle
Sylvian fissure Major horizontal fissure that             and fourth ventricle) along the cerebrospinal
   separates the temporal lobe from adjacent parts        fluid pathway.
   of the frontal and parietal lobes.                  Vermis Midline part of the cerebellum that par-
Tandem gait Walking heel to toe in a straight             ticipates in truncal balance and gait.
   line.                                               Vertigo Illusion of abnormal spinning move-
Tics Abrupt, transient, repetitive, stereotypical         ment by the individual or his environment.
   movements of face and limbs or vocalizations        Watershed brain territory Cerebral cortex
   that may be briefly voluntarily suppressed but is       located between the distal ends of the middle
   often then followed by a burst of tics when the        and posterior cerebral arteries (parietal lobe)
   suppression is removed.                                and middle and anterior cerebral arteries (ante-
Tonsillar herniation Downward movement of                 rior frontal lobe) that are damaged when
   cerebellar tonsils into the foramen magnum in          hypoperfusion of the brain occurs.
   response to increased intracranial pressure         Wernicke’s aphasia Language disorder in which
   from localized mass in the posterior fossa.            there is loss of ability to comprehend verbal or
Tonsils Most inferior part of the midline cere-           written communications and ability to speak in
   bellum.                                                fluid sentences with normal melody that make
                                                          no sense.
Transient ischemic attack Focal neurologic
   signs from transient occlusion of a cerebral        White matter Central nervous tissue that con-
   artery that usually last less than an hour but         tains mainly myelinated (white appearing)
   always less than 24 hours.                             nerve fibers, but not their neuronal cell bodies.
Triceps jerk Deep tendon reflex elicited by tap-        Xanthochromia Yellow color of CSF super-
   ping the triceps tendon above the back of the          natant that comes from lysed RBCs, bilirubin,
   elbow.                                                 or very elevated CSF protein concentration.


To top