Glossary: Some medical terms you may not know

Term
Definition
Apnea
to stop breathing intermittently, may be due to compression on the brainstem.

Arachnoid
one of the three membranes covering the brain, appears to resemble a spider web. There are 3 layers of covering of the brain and spinal cord- the pia, arachnoid and dura.

Arachnoiditis
inflammation of the arachnoid

Aspirate
inhaling fluids into the lungs. (Inability to swallow properly can allow fluid into the lungs.)

Ataxia
inability to coordinate movement. Stumbling when walking, or inability to maintain a fluid gait when asked to walk a straight line.

Atrophic
changes in the muscle that create an appearance of being wasted away

Atrophy
wasting away of the muscle, often due to lack of use or inability to exercise a muscle.

Basilar Invagination
the base of the skull and the first cervical vertebra dent inward, causing pressure on the brainstem or upper cervical spinal cord.

Catheter
small, soft plastic tube used to drain fluid. A Foley catheter is often inserted into the bladder for surgery. A shunt catheter can be inserted into a syrinx or the ventricles of the brain.

Cerebellum
the lower part of the brain that lies in the posterior fossa and is responsible for coordination and fluidity of movement.

Cerebrospinal Fluid
clear, water-like fluid that flows around the brain and spinal cord, and acts to cushion the structures. The total CSF volume in an adult is about 150ml (or about 1 pint).

Cervical
pertaining to the neck

CINE MRI
or CINE MRI flow-study is a special test that looks at the flow of cerebrospinal fluid around the posterior fossa and into the spinal canal.

Clonus
abnormal, uncontrolled jerking of the foot when the ankle is jerked upward.

Cranial nerves
a set of 12 nerves in the brain that control motor and sensory functions.

Diplopia
symptom of seeing double, or double vision

Dura Mater
the tough outer covering of the brain. Lies below the skull.

Dysequilibrium
inability to maintain proper balance. Often noted as stumbling or falling to one side.

Dysesthesia
an unpleasant sensation. A symptom of pins and needles or tingling when skin is touched.

Dysphagia
inability to swallow properly. Often leads to aspiration.

Ectopia
abnormal herniation, displacement or hang down of tissue

Electrocautery
a small instrument that uses heat and is used in many surgeries to stop bleeding.

Hemisphere
one half of the upper portion of the brain.

Herniation
abnormal protrusion (or overhang) of tissue. Some MRI reports will read herniation of the tonsils- this means the tonsils are hanging down too far.

Hoffman's sign
(or reflex) an abnormal reflex that is tested by placing the fingers in a neutral position, and (painlessly) flicking the nail of the middle finger. If positive, the other fingers will abnormally flex in response.

Hydrocephalus
Abnormal, over filling of the spinal fluid pockets (ventricles) in the brain. Can cause symptoms such as headache, balance problems, incontinence and memory problems.

Hydrosyringomyelia
a fluid cavity in the spinal cord. May also be referred to as syrinx, or syringomyelia.

Incidental Finding
a finding that is unexpected, or unrelated to symptoms. May refer to a person who has a finding on MRI, but has no symptoms.

Laminectomy
removal of the roof bone (or posterior arch) of a vertebra.

Limb ataxia
inability to maintain fluid movement of the arm or leg. Inability to touch finger to nose properly.

Lumbar
referring to the lower most part of the spine, the low back.

Meninges
the 3 layers of covering that surround the brain and spinal cord. Consists of the pia mater, the arachnoid, and the dura mater.

Meningitis
inflammation of the meninges. May be due to bacterial or viral infection.

Myelogram
special radiology study that involves injecting contrast dye into the spinal canal and taking x-rays of where the dye travels. The test is often followed by a CAT scan of the area. The test is often done to determine if there is blockage of flow or a nerve root that is being compressed. This test is less commonly used than MRI.

Myelomeningocele
herniation or protrusion of the spinal cord through a defect in development of the neural tube- seen in infants. Often associated with Chiari type II.

Nystagmus
abnormal bobbing of the eyes. Can be seen when looking to the side or up and down.

Parasthesia
abnormal sensation in the extremity.

Pericranium
a muscle layer between the skull and scalp.

Periosteum
a muscle layer between the skull and scalp. (Called pericranium when on the skull).

Posterior Fossa
A general term for the back area of the brain. This is where the brainstem, cerebellum and cerebellar tonsils lie.

Shunt
small, soft plastic tube that is used to drain fluid.

Sleep apnea
to stop breathing intermittently when sleeping. Symptom can be described as waking up short of breath or gasping for air.

Syncope
Spells of passing out, or fainting (loss of consciousness). Different from a seizure.

Syringomyelia
the condition of having an abnormal fluid cavity in the spinal cord

Syrinx
abnormal fluid cavity in the spinal cord

Tethered cord
When the spinal cord becomes stuck to the surrounding structures

Thoracic
refers to the area from the shoulder blades, through the ribs, to about the beltline.

Tinnitus
ringing in the ears.

Tonsillar ectopia
a small amount of hang down of the tonsil tissue of the cerebellum.

Tonsils
a small, often rounded mass of tissue. There are several tonsils in the body, including in the throat, in the intestine, or in the brain. In reference to Chiari, indicates the tissue tucked behind the cerebellum that protrudes downward, causing a plug effect.

Ventricle
fluid pocket in the brain (4 in all), that holds spinal fluid. Enlargement of the ventricles can be called hydrocephalus