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Neuroscience: Common Terms


An abnormal bulging or stretching of a weakened wall of a blood vessel. Cerebral aneurysms are usually of three types: saccular with a narrow “neck” (also known as “berry” aneurysms because of their shape and their occurrence in clusters); saccular with a broad base; and fusiform, in which a section of artery bulges all the way around.


The tough outer ring of the spinal disc.


Inflammation of the arachnoid membrane, most commonly seen within the spinal cord around the spinal cord and cauda equina.

Arteriovenous malformation

A collection of blood vessels with one or several abnormal communications between arteries and veins that may cause hemorrhage or seizures.


Commonly used term that describes a disorder that causes inflammation and pain of the joints.


Surgical fixation or fusion of a joint.


A tumor within the substance of the brain or spinal cord made up of astrocytes, often classified from Grade I (slow-growing) to Grade III (rapid-growing).

Brain tumor

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain (secondary, or metastatic brain tumors). Treatment options depend on the type of brain tumor you have, as well its size and location.

Burst fractures

Type of traumatic spinal injury in which a vertebra breaks from a high-energy axial load (e.g., car accidents or falls from a great height or high velocity), with all or pieces of the vertebra shattering into surrounding tissues and sometimes the spinal canal. The burst fracture is categorized by the severity of the deformity, the severity of spinal canal compromise, the degree of loss of vertebral body height, and the degree of neurologic deficit.

Cauda equina

The bundle of long spinal nerve roots arising from the end of the spinal cord and filling the lower part of the spinal canal (from approximately the thoraco-lumbar junction down). These long nerves resemble a horse’s tail (cauda equina).


This is the second largest area of the brain, consisting of two hemispheres and located just above the brainstem, beneath the occipital lobes at the base of the skull. It connects the brain to the brain stem.

Cerebral spinal fluid analysis (spinal tap)

Often crucial in making the diagnosis of a bleeding disorder, tumor or infection of the brain or spinal cord. Under local anesthesia, fluid is withdrawn from the spinal column.

Cerebrospinal fluid (CSF)

A clear, water-like fluid which circulates around the brain and spinal cord.


The principal portion of the brain, which occupies the major portion of the interior of the skull and controls conscious movement, sensation, and thought. Separated into right and left hemispheres.

Cervical spine

Upper spine, neck; it usually consists of seven vertebrae.

Chiari malformation

The downward (caudal) displacement of part of the cerebellum or brainstem below the foramen magnum. May also have hydrocephalus or cord symptoms.

Compression fracture

A collapse of a vertebra. It may be due to trauma or due to a weakened vertebra in a patient with osteoporosis.

Computerized tomography (CT) scan

Computer assisted tomography is a form of radiology or X-ray that uses computers to construct two-dimensional pictures of selected body parts. Dye may be injected into a vein to obtain a better picture.


A disruption, usually temporary, of neurological function resulting from a blow or violent shaking.


Surgical opening of the skull, usually by creating a flap of bone.

Degenerative disc disease

Flattening or “wear and tear” of the disc.


The intervertebral disc – cartilaginous cushion found between the vertebrae of the spinal column. It may bulge beyond the vertebral body and compress the nearby nerve root, causing pain. The terms “slipped disc,” “ruptured disc,” and “herniated disc” are often used interchangeably even though there are subtle differences.


The inflammation of an intervertebral disc commonly caused by infection.

Diskogenic back pain

Pain caused by a condition related to the intervertebral discs of the spine. Common disc abnormalities include bulging discs and herniated discs.

Electroencephalography (EEG)

An electroencephalogram (EEG) records the brain’s continuous electrical activity by means of electrodes attached to the scalp. It is used to help diagnose structural disease of the brain and episodes such as seizures, fainting, or blacking out. It is painless and requires little preparation.

Electromyography (EMG)

An electromyogram (EMG) measures and records electrical activity from the muscles and nerves. This may be helpful in cases of pain, numbness, tingling, or weakness. Because small needles are inserted into the muscle and mild electrical shocks are given to stimulate the nerve, slight discomfort is experienced.


Immediately outside the dura mater. Same as extradural.

Facets/facet joint

Each of four joints formed above and below and on either side of a vertebra. The lower bony projection of one vertebra meets the upper projections of the vertebra below it, forming facet joints.

Foot drop (drop foot)

A simple term for a potentially complex problem. It is usually a symptom characterized by the inability or difficulty in moving the ankle and toes upward (dorsiflexion). In walking, while stepping forward, the front of the foot must be lifted upward to prevent the foot from dragging along the ground.


A hole or opening that acts as a passageway for nerves or blood vessels.

Glioblastoma multiforme

A rapidly growing tumor composed of primitive glial cells, mainly arising from astrocytes.

Herniated nucleus pulposus (HNP)/herniated disc

The extrusion of the central portion (nucleus) of an intervertebral disc through the outer cartilaginous ring (annulus). The herniated portion can compress the spinal cord or nerves in or exiting the spinal canal.


A condition, often congenital, marked by abnormal and excessive accumulation of cerebrospinal fluid in the cerebral ventricles. This dilates the ventricles and increases intracranial pressure.

Internal fixation

The insertion of metal rods, wires, pins, screws, or plates (or a combination of these) into bone fragments.


The portion of bone that extends from the pedicle and curves around to complete the vertebral arch on the right and left sides.

Low back pain

Any type of discomfort in the lumbar (lower) region of the spine; the pain may be due to muscular strain, bone fracture, nerve impingement, or a wide range of other conditions.

Lumbar Spine

Lower spine, lower back; it usually consists of five vertebrae.

Magnetic resonance imaging (MRI)

MRI is an advanced way of making pictures of what is inside the body. It is harmless and involves no radiation. It is performed by lying still in a small chamber for about 30 minutes. Because MRI uses a very strong magnet, if you have any metal other than dental fillings, you should notify your physician.


An inflammation or infection of the meninges.

Mid back pain

Any type of discomfort in the thoracic (middle) region of the spine; the pain may be due to muscular strain, bone fracture, nerve impingement, or a wide range of other conditions.


A myelogram may be helpful in patients who have neck or back pain or suspected spinal tumors. Dye is injected into the spinal canal, making the structure clearly visible to X-rays. This test requires hospitalization.


Any functional or pathologic disturbance in the spinal cord.

Neck pain

Any type of discomfort in the cervical (upper) region of the spine; the pain may be due to muscular strain, bone fracture, nerve impingement, or a wide range of other conditions.

Neuropathy/neuropathic pain

Any functional or pathologic disturbance in the peripheral nervous system. Localized secondary to lesion or generalized, secondary to medical disorder.


A disorder in which bone is abnormally brittle, less dense, and is the result of a number of different diseases and abnormalities.

Pinched nerve

A nerve that has become constricted by surrounding tissue.

Piriformis syndrome

Neuromuscular disorder that occurs when the sciatic nerve is compressed or otherwise irritated by the piriformis muscle causing pain, tingling, and numbness in the buttocks and along the path of the sciatic nerve descending down the lower thigh and into the leg.

Pituitary tumor

These tumors are usually nonmalignant. Because the pituitary gland secretes hormones, some pituitary tumors mimic this and may flood the body with abnormal amounts of hormones.


Impairment of a nerve root, usually causing radiating pain, numbness, tingling, or muscle weakness that corresponds to a specific nerve root.

Sacrioilic joints

The sacroiliac (SI) joints are formed by the connection of the sacrum and the right and left iliac bones. The sacrum is the triangular-shaped bone in the lower portion of the spine, below the lumbar spine. SI joint inflammation can cause pain in the low back, back of hips, groin, and thighs.


A term indicating pain along the course of a sciatic nerve, especially noted in the back of the thigh and below the knee.


Lateral (sideways) curvature of the spine.


A tube which diverts body fluid from one body cavity or vessel to another.

Spinal cord injury

Refers to any injury to the spinal cord that is caused by trauma instead of a disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence. Spinal cord injuries are described at various levels of “incomplete” that can vary from having no effect on the patient to a “complete” injury that means a total loss of function.

Spinal fusion

Operative method of strengthening and limiting motion of the spinal column. Can be performed with a variety of metal instruments and bone grafts, or bone grafts alone.

Spinal instability

Damage to a disc or tearing of the ligament holding the spine, which causes the spine to be unable to carry out its supporting function.


Forward displacement or slippage (subluxation) of one vertebra over another.


Degenerative bone changes in the spine usually most marked at the vertebral joints with bony spur formation.


Narrowing of the openings of the foramen and/or the spinal canal.


Located below the dura mater and above the arachnoid meninges.

Thoracic spine

Mid spine, middle of back; usually consists of 12 vertebrae.

Transsphenoidal approach

Operative method of reaching the pituitary gland or skull base traversing the nose and sinuses.

Traumatic brain injury (TBI)

A form of acquired brain injury that occurs when a sudden trauma causes damage to the brain. TBI can result when the head suddenly or violently hits an object, or when an object pierces the skull and enters brain tissue

Trigeminal nerve

The fifth and largest cranial nerve. It is mainly sensory except for a small motor branch that supplies the muscles for chewing. The branches of the trigeminal nerve provide sensation to the eye and forehead, midface, and upper and lower jaw.

Vertebral column

Column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It houses and protects the spinal cord in its spinal canal.

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