Neurological Medical Terms

Medical terms can be confusing. When dealing with nervous system disease you may be exposed to many new neurological medical terms which are confusing and do not make sense to you or your loved ones. It can be helpful to have somewhere to go to get more information about what they mean and what they imply in the discussion of a patient.

Below is a list of several basic terms often used when discussing the nervous system and neurological diseases. Many link to other pages on this site where you can learn more about them.

If you cannot find any particular neurological medical terms, use our Site Map and Search function to search the site for other areas where it may be explained. If you still cannot find what you are looking for, it is possible we do not yet have it on our site. In that case, please Contact Us and let us know. We work tirelessly to post new material including new neurological medical terms often so that we can meet the needs of all of our readers.

Neurological Medical Terms

aneurysm: An aneurysm is an abnormality of a blood vessel. It is a weakening of the wall of an artery that leads to a progressive ballooning out of the wall, forming a sac filled with blood. Aneurysms can occur in many arteries throughout the body but ones that occur in the head in the blood vessels that supply the brain are called cerebral aneurysms. They can rupture and lead to subarachnoid hemorrhage.

aneurysm coiling: A relatively new treatment for cerebral aneurysms, coiling uses small metal coils to fill the aneurysm from the inside, rather than clipping it from the outside. The goal is to fill the aneurysm as completely as possible so that it can clot off and no blood can continue to enter the aneurysm, preventing rupture. This procedure is performed through endovascular techniques, meaning that a catheter is placed into the artery (through the femoral artery in the leg generally) and slowly maneuvered up to the blood vessels in the head. This is controlled by x-ray. Coiling is performed by either an interventional neuroradiologist or a neurosurgeon trained in endovascular techniques.

aneurysm clipping: One of the treatment options for a cerebral aneurysm is called surgical clipping. This is a procedure which is performed through an opening in the skull, a craniotomy. The aneurysm is exposed and then the base of it is clipped with a small metal clip called an aneurysm clip. This prevents blood from getting into the aneurysm so that it cannot rupture in the future. Clipping of aneurysms is performed by a neurosurgeon.

Arnold Chiari malformation: Sometimes just called Chiari malformation, this is a malformation of the base of the brain and skull where the brain stem exits the skull to become the spinal cord. Where are several sub-types of Chiari malformation which vary somewhat in their causes and symptoms. However, most have the common feature that a part of the cerebellum, called the cerebellar tonsils, descend down lower than they should, through the opening in the skull called the foramen magnum ("foramen" means hole and "magnum" means large). This decent leads to crowding of the area which can cause compression of the brain stem and nerves in the area, often leading to headache and neurological symptoms. For more information, see our Arnold Chiari Malformation Section.

brain stem: The brain stem is the lower and more primitive part of the brain. It is made up of three parts, from top to bottom, the midbrain, the pons and the medulla oblongata. Many nerve fiber tracts and nuclei (collections of nerve cells) occupy this small area and therefore the brain stem has many important functions. In particular, the brain stem is very important for basic alertness and the level of consciousness. Significant damage to the brain stem can lead to impairment of consciousness, leading to coma or death. It can also have profound effects on many other neurological functions, including normal breathing. At the bottom end of the brain stem, as the medulla passes through the foramen magnum (the large hole in the bottom of the skull), it is continuous with the spinal cord which continues down the spinal canal in the spine.

central nervous system: The central nervous system, or cns, refers to the brain, brain stem and spinal cord. It is distinct from the peripheral nervous system which includes all the peripheral nerves which go in and out of the central nervous system.

cerebellum: The cerebellum (or "little brain") is a part of the brain which lies just behind the brain stem. It is important for motor coordination. Damage to the cerebellum can lead to imbalance, clumsiness and problems with gait, among other neurological symptoms.

cerebrospinal fluid: Cerebrospinal fluid, or CSF, is the water-like fluid that is within the brain, in chambers called the ventricles, as well as surrounding the brain and spinal cord in an area called the subarachnoid space. All of the functions of this fluid are not well known but it is clearly important for the support and protection of the brain and spinal cord.

cerebrum: The cerebrum literally means the brain. However, it refers to the forebrain, the most advanced part of the brain which primarily includes the two cerebral hemispheres.

congenital: A congenital condition is one which a patient is born with. It does not necessarily imply a genetic or hereditary cause, simply one that began before birth and the individual has had since the time of birth.

craniectomy: A craniectomy is a medical term referring to a surgical opening of the skull. However, whereas in a craniotomy the bone is re-attached at the end of the procedure, in a craniectomy the bone is left out, leaving an opening in the skull. A craniectomy is performed for various reasons, usually to decompress the structures contained within the bone. For example, in severe traumatic brain injury a large craniectomy may be performed to allow the brain room to expand while it swells.

craniotomy: A craniotomy is a medical term referring to a surgical opening of the skull. This is performed frequently in neurosurgical operations to achieve access to the brain and other structures within the head. Typically, at the end of the procedure, the piece of bone that was removed is secured back into place, usually with titanium plates and screws but sometimes with wire or suture.

CSF: CSF is an abbreviation for cerebrospinal fluid (see above).

decompression: Decompression is a general medical term that is often used in surgical procedures which aim to decrease the pressure on a certain area of the nervous system. For example, a decompressive craniectomy is the removal of a piece of skull to allow the brain to expand after an injury. Another example is a laminectomy of the spine which may aim to decompress the spinal canal so that the spinal cord or nerves are no longer compressed.

epilepsy: This is the medical term for a condition of recurrent seizures. There are many causes which can lead to epilepsy in an individual, including brain tumors, cerebrovascular malformations, trauma, and congenital malformations of the nervous system, to name a few. Learn more about epilepsy and seizures in our Epilepsy section.

gray matter: The gray matter of the brain and spinal cord is tissue which is mostly composed of nerve cell bodies. These are the areas where the nerve cells actually reside. These areas are often called a nucleus or nuclei if it occurs within the brain, brain stem or spinal cord. On the surface of the brain, particularly on the surface of the cerebral hemispheres and the cerebellum, there is gray matter which is called the cortex. The cortex is the wiggly area on the surface of the brain which gives it its characteristic noodle-like appearance.

hematoma: A hematoma is a collection of blood. It can occur due to spontaneous bleeding, such as from the rupture of an arteriovenous malformation, or due to traumatic brain injury, such as an epidural hematoma or a subdural hematoma.

hemorrhage: Hemorrhage is a general medical term for bleeding. Bleeding into a confined space can lead to a collection of blood called a hematoma (see above). It can also lead to bleeding into an area such as the cerebrospinal fluid, known as subarachnoid hemorrhage.

hydrocephalus: Hydrocephalus is a general medical term for the spectrum of disorders that are due to an abnormality in the normal dynamics of the cerebrospinal fluid (CSF) in and around the brain and spinal cord. There are several causes and sub-types of hydrocephalus but in general these disorders lead to an accumulation of CSF in the head which increases the pressure on the brain and can lead to neurological damage and symptoms.

ICP: ICP is an abbreviation from intracrantial pressure (see below).

infarction: An infarction is the death of tissue due to inadequate blood flow (ischemia) to the tissue. Infarction of the heart muscle is known as a myocardial infarction (heart attack) while infarction of the brain is generally known as a cerebral infarction (stroke or ischemic stroke). Tissues need blood to supply oxygen and nutrients and to remove waste products. Without a certain critical level of blood flow, cells start to malfunction. At some point they become permanently damaged, leading to death of the cells, which is infarction.

intracranial: Intracranial is a general medical term that means "within the cranium" or "within the head". It is used to identify diseases of the brain and other areas within the skull. For example, an intracranial aneurysm or an intracranial hemorrhage.

intracranial pressure: The intracranial pressure, or ICP, is the pressure inside the skull. This is one of the medical terms heard often in the treatment of patients with head trauma. Because the space inside the bony skull is fixed, any increase in mass within the skull will increase this pressure. This can be due to several things including a mass inside the head (such as a brain tumor or a hemorrhage/hematoma), swelling of the brain due to traumatic injury or infarction, and hydrocephalus. Generally, as the pressure increases the brain does not function as well, leading to neurological symptoms. Very high intracranial pressures can cause coma or death. Patients with disorders that lead to high pressure are often monitored with some form of intracranial pressure monitor, such as a ventriculostomy, to record the pressure. Several treatments can be then used to help lower the pressure to protect the brain.

ischemia: Ischemia is the lack of adequate blood flow to support the normal functioning of a tissue such as the brain. As the tissue becomes ischemic, it does not function normally and can lead to neurological symptoms. If the ischemia is severe enough or prolonged enough it can lead to permanent damage to the brain tissue which is termed infarction (see above).

lesion: Lesion is one of the general medical terms for an abnormality in the body. Several pathologies can be called a lesion, such as a hematoma, a brain tumor or a cerebral infarction.

mass: A mass is any lesion which takes up space in the head. For example, a hematoma (a collection of clotted blood) can be called a mass since it takes up space. Also, a tumor of any type could be termed a mass. Generally, a mass can cause symptoms by compressing the normal structures to which it is adjacent. Mass does not imply that a lesion is cancer, a tumor or anything else specific, it just refers to a mass that takes up space in the head.

nerve: A nerve is a collection of nerve fibers. Each of the nerve fibers within a nerve are tiny extensions of neurons (the nerve cells in the brain and spinal cord) which carry electrical impulses down them at very fast speeds. Therefore, a nerve is generally carrying information to or from the central nervous system. The nerves going from the central nervous system include nerves that control some function of the body, such as increasing or decreasing heart rate or telling a muscle to contract. Nerves coming back into the central nervous system are typically carrying some sensory information from the environment, including touch sensation, hearing, taste, etc.

neurologist: A neurologist is a medical specialist who specializes in diseases of the nervous system. The neurologist focuses on the medical treatment of these diseases since they are not trained in surgery. Diseases that require some surgical treatment will usually be referred to a neurosurgeon.

neurosurgeon: Also known as a brain surgeon or neurological surgeon, a neurosurgeon is a surgeon trained specifically to treat disorders of the nervous system. This can include everything from intracranial diseases to diseases of the spine. However, many neurosurgeons sub-specialize in one or more area of neurosurgery such as epilepsy, traumatic brain injury, spinal disease, brain tumors, pediatric neurosurgery, movement disorders (such as Parkinson's Disease) or cerebrovascular diseases (diseases of the blood vessels).

peripheral nervous system: The peripheral nervous system includes all parts of the nervous system that is external to the central nervous system (see above). In general this includes all the nerves going to and coming from the central nervous system, including the autonomic nerves and ganglia which control autonomic functions in the body.

seizure: A seizure is a sudden occurrence of abnormal, uncontrolled electrical activity in the brain. There are many causes of seizures and they can cause various sensory disturbances, loss or alteration of consciousness, convulsions and other symptoms depending on the type and location in the brain. A condition of recurring seizures is called epilepsy. Learn more about seizures and epilepsy in our Epilepsy section.

spasm: Spasm is a general medical term for a sudden involuntary muscle movement. Like some other medical terms, it can be used to refer to a variety of disorders, from benign muscle spasm which can occur with muscle injury or excessive activity to seizure activity due to epilepsy. Therefore it is not a specific term that implies any one particular disease or pathology.

spinal cord: The spinal cord is the long extension of the central nervous system which occupies the spinal canal in the spine. The bony spine and the ligaments, muscles and other soft tissues that surround it all help protect the spinal cord. The cord carries information up to the brain and down from the brain to the periphery. It also contains the motor neurons (nerve cells) which send out fibers to all muscles to control their movement.

stroke: Stroke is a general term for the sudden onset of neurological symptoms. While stroke can be used in this general way to refer to various diseases including spontaneous hemorrhage such as subarachnoid hemorrhage due to the rupture of an intracranial aneurysm, most commonly it is used to refer to an ischemic stroke or cerebral infarction. This type of stroke is most commonly caused by a blood clot which obstructs the normal flow of blood in one of the arteries that supplies blood to the brain. This interruption in blood flow can lead to injury and death of the brain tissue which is supplied by that artery.

tumor: Tumor is one of the general medical terms which refers to any mass. However, for the most part the term is used to describe a group of abnormal cells which grows due to the uncontrolled growth of the cells. The type of tumor is generally defined by the origin of the tumor, which cell types from which it arose. Tumors also vary in their behavior, grown rate and invasiveness. Slower growing, less aggressive tumors are generally defined as "benign" whereas faster growing, more aggressive tumors are termed "malignant". Malignant tumors are also known as cancer. Tumors can occur almost anywhere in the body but there are several types of brain tumors which either grow within the brain tissue itself or arise from tissues in the head near the brain and can therefore involve the brain or nerves coming from the brain. There are also spinal tumors which grown within or involve the spine.

ventriculostomy: A ventriculostomy is a catheter which is placed within the ventricles (the fluid-filled spaces within the brain). It can be used to drain cerebrospinal fluid to decrease the pressure within the head, such as in the case of hydrocephalus or traumatic brain injury. It can also be hooked up to a monitor to record the intracranial pressure.

white matter: The white matter is the tissue in the brain and spinal cord which is made up mostly of nerve fibers (the axons) which carry electrical impulses from one part of the nervous system to another. White matter contains few actual cell bodies, as opposed to gray matter where the cell bodies reside.

We hope this collection of neurological medical terms helps clarify the lingo and medical terms that are often used in dealing with neurological disorders. If you were unable to find any neurological medical terms, use our Site Map and Search function to search our site for medical terms. If you still cannot find the medical terms you are looking for, it is possible we do not yet have it on our site. In that case, please Contact Us and let us know. We try to update the site and medical terms page as frequently as possible to meet all the needs of our visitors.