This glossary is a compilation of terms that have been used in various articles in Chiari & Syringomyelia News. As such, it is not intended to be a complete glossary, but it is a good start and it will be updated periodically with new words and definitions. While we have strived to be as accurate as can, some medical terms are ambiguous and are often used differently by different people. We make no claim or guarantee as to the accuracy of these definitions. This glossary is intended for informational purposes only. We strongly encourage anyone with medical questions to seek professional medical advice.

Special thanks to Scott Emery for putting this together:



acetaminophen - common, over-the-counter pain reliever; found in Tylenol

acetazolamide - also known as Diamox; medicine used to lower elevated ICP

acute - of short duration

afferent pathways - nerve paths that carry signals from the periphery - like the hand - to the spinal cord and brain

allodynia - pain in response to something that should not cause pain, like a light touch

analgesia - absence of pain in response to something that should be painful

analgesic - a drug that relieves pain

anterior - at or near the front of something

antiemetic - drug used to control nausea and vomiting

apnea - temporary stop in breathing, sleep apnea

arachnoid - middle-layer of the the membranes which cover the brain and spinal cord

aspiration - act of inhaling

asymptomatic - having no symptoms

ataxia - loss of coordination and balance due to nerve damage; trouble walking

atrophy - wasting away, withering

audiometric - having to dear with hearing tests

autologous - derived, or taken, from a person's own body

axial - along the centerline, in the case of the human body, along the neck or spine


basilar invagination - condition, sometimes associated with Chiari, where the C2 vertebra is displaced upward, potentially compressing the brainstem

benign - not dangerous to your health

bovine - derived from a cow or bull

brainstem - the lowest part of the brain which connects with the spinal cord and controls automatic functions such as breathing and swallowing


cadaver - a dead body; corpse

cardiac - relating to the heart

case study - type of research which focuses on one subject, or person, as opposed to a group of subjects

caudal - towards the tail, in the case of CSF flow, from the skull to the spine

causalgia - a constant, burning type pain

central canal - very center of the spinal cord, so named because it starts as a hollow tube which closes in most people as they age

central nervous system - the brain and spinal cord

central pain - abnormal pain arising from damage to the central nervous system

central sleep apnea - sleep apnea due to a delay in the nerve signal from the brain to breathe

cephalad - towards the head, in the case of CSF flow, from the spine to the skull

cephalgia - headache

cerebellar tonsils - portion of the cerebellum located at the bottom, so named because of their shape

cerebellum - part of the brain located at the bottom of the skull, near the opening to the spinal area; important for muscle control, movement, and balance

cerebrospinal fluid (CSF) - clear liquid in the brain and spinal cord, acts as a shock absorber

cervical - the upper part of the spine; the neck area

Chiari malformation (CM) - condition where the cerebellar tonsils are displaced out of the skull area into the spinal area, causing compression of brain tissue and disruption of CSF flow

Chiari II - more severe form of malformation which involves descent of parts of the brainstem and is usually associated with Spina Bifida

chronic - of long duration, long lasting

cine MRI - type of MRI which can show CSF flow

cisterna magna - CSF filled space below the cerebellum

Cobb Angle - technique used to measure the severity of a spinal curve - in degrees - from spinal images

Color Doppler Ultrasound (CDU) - type of ultrasound which can detect flow of blood and CSF

complete spinal cord injury - type of spinal injury where there is no feeling or motor control below the level of injury

control group - in a study, a group of subjects who are used as a basis for comparison; the control group is usually healthy, or does not receive a treatment that the experimental group receives

cranial nerve - one of 12 pairs of nerves that originate in the brain as opposed to the spinal cord

craniocervical junction - the area where the skull and spine meet


decompression surgery- common term for any of several variations of a surgical procedure to alleviate a Chiari malformation

diabetic neuropathy - nerve damage as a result of diabetes

displaced fracture - type of fracture where the two parts of broken bone are separated, or displaced, from each other

dorsal - referring to the back of something, can also refer to the top

dorsal horn - also known as the posterior column, part of the spinal cord located in the back part of the cord where many afferent nerve pathways are located, note there is a right and left dorsal horn

double blind - scientific technique used to eliminate bias in a study, where neither the study participant nor the experimenter (doctor) knows which of two treatments the participant is receiving

Dr. Max van Manen - scientist who developed a phenomenological research method which is widely used

dura - thick outer covering of the brain and spinal cord; beneath the dura are the arachnoid and the pia

dural scoring - surgical technique where a series of cuts are made into the dura, but the dura is not completely opened

duraplasty - surgical technique where a patch is sewn into the dura

dysesthesia - an unpleasant, or painful, response to a normal stimulus; for example pain from being touched lightly

dysphagia - trouble swallowing


ectopia - abnormal position; in the case of Chiari, the cerebellar tonsils

elastic - something that returns to it's original shape after being stretched, compressed, or deformed; a rubber band is elastic

etiology - the cause of a disease


foramen magnum - large opening at the base of the skull, through which the spinal cord passes and joins with the brain

fracture - break in a bone

fusion - surgical procedure where vertebra are joined together using bone grafts and often instruments such as rods, screws, etc.


gastroesophageal reflux (GER) - reflux of stomach contents into the esophagus

graft - material, or tissue, surgically implanted into a body part to replace or repair a defect


hermeneutic - interpreted

hydrocephalus - condition where there is an abnormal collection of CSF in the skull area

hydromyelia - cyst in, or swelling of, the central canal; sometimes used interchangeably with syringomyelia

hyperesthesia - abnormal sensitivity to stimulation

hypertension - abnormally high blood pressure

hypopnea - slow or shallow breathing

hypoesthesia - decreased sensitivity to sensation

hypotension - abnormally low blood pressure


ibuprofen - common, over-the-counter, anti-inflammatory pain reliever; found in Motrin

ICP - intracranial pressure; pressure of the CSF inside the skull

idiopathic - due to an unknown cause

idiopathic growth hormone deficiency - abnormally low level of growth hormones due to an unknown cause

Idiopathic Intracranial Hypertension (IIH) - condition where ICP is elevated for unknown reasons; see other side bar

incomplete spinal cord injury - type of spinal injury where there is some feeling or motor control below the level of the injury


Klippel-Feil syndrome - congenital condition where 2 or more cervical vertebra are fused together; often associated with other neurological conditions


laminectomy - surgical removal of part (the bony arch) of one or more vertebrae

lumbar - the lower part of the spine

lumbar puncture (LP) - procedure where a hollow needle is inserted into the spinal area (near the base) in order to measure/relieve pressure or withdraw CSF for testing


meninges - the three membranes that cover the brain and spinal cord (singular: meninx)

meningitis - inflammation of the meninges, usually due to a bacterial infection but sometimes from viral, protozoan, or other causes (in some cases the cause cannot be determined)

meningocele - protrusion of the membranes that cover the spine and part of the spinal cord through a bone defect in the vertebral column

metopic - relating to the forehead or front part of the skull

MRI - Magnetic Resonance Imaging; diagnostic device which uses a strong magnetic field to create images of the body's internal parts


narcotic - class of drugs derived from the opium plant - or created synthetically for the same effect; used as pain-killers

neurofibromatosis - set of genetic disorders in which tumors grow on different types of nerves, bone and skin; type 1 is characterized by spots on the skin

neuropathic - having to do with damage to a nerve

neuropathic pain - pain due to nerve damage, often severe and often described as burning

neurotologist - an ear-nose-throat medical specialist who obtains an additional subspecialty in conditions of the ear

nociceptive - pain associated with a painful stimulus, such as a joint problem

normative - normal; statistically, the results of testing a large body of people

NSAID - non-steroidal anti-inflammatory; class of pain relieving drugs which includes ibuprofen, naproxen (Alleve), and others

nystagmus - involuntary, rapid eye movements


obstructive sleep apnea - sleep apnea due to an obstruction in the throat

occipital - relating to the back part of the head

ORIF - open reduction and internal fixation; surgical technique to correct spinal injuries where instruments, such as rods, screws, and plates, are used

opioid - narcotic

oropharyngeal - having to do with the throat or throat area

otology - scientific study and treatment of the ear

otolaryngologist - doctor who specializes in the ear, nose, and throat


PND - painful neuropathic disorder; any painful disorder where the pain is caused by nerve damage; such as diabetic neuropathy or post-herpetic neuralgia

papilledema - swelling/bruising of the optic nerve due to increased ICP

paresthesia - abnormal sensation, such as burning

pericardium - tissue surrounding the heart

pericranial - from the periosteum, dense connective tissue which covers the skull

peripheral pain - pain arising from the outer - or peripheral - nervous system, the ends of the nerves

phase contrast MRI - type of MRI which can measure the velocity of CSF

phenomenological - relating to experiences; phenomenological research emphasizes the importance of how people experience and feel things

photophobia - sensitivity, sometimes painful, to light

placebo - a fake medicine - which has no effect - used in scientific studies as a control

polysomnography - studying physical measures - such as breathing - during sleep in a controlled environment

post-herpetic neuralgia - painful nerve damage as a result of "shingles" (herpes zoster)

post-traumatic syringomyelia - syringomyelia which develops after a spinal cord injury

posterior - at or near the back of something

posterior fossa - depression on the inside of the back of the skull, near the base, where the cerebellum is normally situated

prospective - type of study where the experiment is designed before the data is collected

pseudotumor cerebri - another name for IIH; so named because the symptoms mimic the presence of a tumor


qualitative research - type of research which uses words and descriptions as data

quantitative research - type of research which uses numbers for data and statistics to analyze results


radicular - relating to the roots; in the case of radicular pain, damage to a nerve root can actually cause pain at the end of the nerve

radiograph - another name for an X-ray; diagnostic machine which uses radiation to create an internal image of the body

randomized - technique used in a scientific study where participants are randomly assigned to one of two groups; used to control the effects of age, gender, etc. on the study outcome

refractory - not responsive to treatment

retrospective - type of scientific study which looks back in time, often at medical records

rigid - something that isn't flexible and won't bend


scoliosis - abnormal curvature of the spine

shunt - a surgically implanted tube used to divert, or drain, CSF

sleep apnea - disruption of breathing during sleep which lasts longer than 10 seconds

spina bifida - myelodysplasia; birth defect where part of the spinal cord develops outside of the body

spontaneous venous pulsations (SVP) - periodic changes in size of veins in the retina (in the back of the eye); absence indicates elevated ICP

stenosis - narrowing or blockage of a passage

stent - tube used to support an opening in the body

stridor - noisy breathing which indicates a problem

subarachnoid space (SAS) - space underneath the arachnoid, but above the actual brain and spinal tissue, which contains the cerebrospinal fluid

suboccipital craniectomy - surgical removal of part of the skull, or cranium, in the back of the head, near the base

syringomyelia (SM) - neurological condition where a fluid filled cyst forms in the spinal cord

syrinx - fluid filled cyst in the spinal cord


tachycardia - rapid heart beat

thoracic - relating to the middle part of the spine, or chest area

tinnitus - ringing in the ears

tonsillar herniation - displacement of the cerebellar tonsils out of the skull; usually measured in mm below the bottom of the skull

tonsillar manipulation - surgically removing part, or all, of the cerebellar tonsils

trachea - the windpipe; tube which carries air to the lungs


ultrasound - imaging technique which uses sound waves to create pictures of internal organs and body parts


Valsalva - straining, a Valsalva headache is one brought on by straining

velocity - how fast something moves in a certain direction

ventral - referring to the front of something; can also refer to the bottom

ventricle - a cavity in an organ, the fourth ventricle is a space in the brain where CSF collects

ventriculo-peritoneal shunt - neurosurgical procedure where a tube-like device is inserted into a ventricle to divert and drain CSF into the peritoneal space in the abdomen

vertebra - segment of the spinal column, noted as region plus number (C = cervical, T = thoracic, L = Lumbar)

vestibular - relating to the balance system; more specifically to the vestibule of the inner ear

voxel - the smallest distinguishable unit of volume; like a 3D pixel

Sources: Chiari & Syringomyelia News;

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