Goodman Campbell Brain and Spine - Indianapolis, Indiana

BRAIN

Terms & Definitions

ANATOMY

Anterior Cerebral Artery: The anterior cerebral artery (ACA) arises from the internal carotid and supplies blood to the medial and superior parts of the frontal lobe and the anterior parietal lobe. The ACA supplies the following key functional areas:

septal area
primary motor cortex for the leg and foot areas and the urinary bladder
additional motor planning areas in the medial frontal lobe, anterior to the precentral gyrus
primary somatosensory cortex for the leg and foot

Anterior Communicating Artery: The anterior communicating artery (ACoA) is a small blood vessel that bridges the two larger anterior cerebral arteries. Together with the posterior cerebral arteries and posterior communicating artery, they form a ring, sometimes called the Circle of Willis, lying at the base of the brain. The ACoA gives rise to a number of small branches, called collaterals. These collaterals supply blood to brain areas including the frontal lobes and the basal forebrain. The ACoA is one of the most common sites of aneurysm in the brain.

Carotid Artery: Large artery on either side of the neck which supplies blood to most of the cerebral hemisphere. Main artery to the head that divides into external and internal carotid arteries.

Cavernous Sinus:

Cerebellum: The portion of the brain (located at the back) which helps coordinate movement (balance and muscle coordination). Damage may result in ataxia which is a problem of muscle coordination and can interfere with a person's ability to walk, talk, eat, and to perform other self-care tasks.

Frontal Lobe: The frontal lobes are considered our emotional control center and home to our personality. They are involved in motor function, problem solving, spontaneity, memory, language, initiation, judgment, impulse control, and social and sexual behavior. The frontal lobes are extremely vulnerable to injury due to their location at the front of the cranium, proximity to the sphenoid wing and their large size. The left frontal lobe is involved in controlling language related movement and the right frontal lobe plays a role in non-verbal abilities.

Middle Cerebral Artery: The middle cerebral artery (MCA) is by far the largest of the cerebral arteries. It branches off the internal carotid and is the vessel most commonly affected by stroke or cerebrovascular accident (CVA). The MCA supplies most of the outer convex brain surface, nearly all the basal ganglia, and the posterior and anterior internal capsules. Infarcts that occur within the vast distribution of this vessel lead to diverse problems as a result of this infarction.

Occipital Lobe: Region in the back of the brain which processes visual information. It is responsible for visual reception and contains association areas that help in the visual recognition of shapes and colors. Damage to this lobe can cause visual deficits.

Parietal Lobe: One of the two parietal lobes of the brain located behind the frontal lobe at the top of the brain. Damage to the right lobe can cause visuo-spatial deficits (e.g., the patient may have difficulty finding their way around new or even familiar places). Damage to the left lobe may disrupt a patient's ability to understand spoken and/or written language. The parietal lobes contain the primary sensory cortex which controls sensation (touch and pressure). Behind the primary sensory cortex is a large association area that controls fine sensation (judgment of texture, weight, size, shape).

Posterior Cerebral Artery: At the level of the midbrain, the basilar artery splits off to form the two posterior cerebral arteries (PCA). Each PCA forms a series of the midbrain and arteries that supply much of the hypothalamus and thalamus. Branches of PCA supply parts of the parietal lobe, temporal lobe, and the occipital lobe.

Temporal Lobe: There are two temporal lobes, one on each side of the brain located at approximately ear level. These lobes allow a person to distinguish smells and sounds. They also help in sorting new information and are believed to be responsible for short-term memory. The right lobe is mainly involved in visual memory (i.e., memory of pictures and faces) while the left lobe is mainly involved in verbal memory (i.e., memory of words and names).

Ventricles: Normal cavities within the brain filled with cerebrospinal fluid. There are two lateral ventricles, a midline third ventricle, and a midline fourth ventricle.

CONDITIONS

Aneurysm: Protrusions of blood vessels that normally occur where blood vessels divide. When they rupture in the brain, they may cause a subarachnoid hemorrhage, which is bleeding around the surface of the brain and under a membrane known as the arachnoid membrane. Aneurysms are usually located near the base of the brain and arise from a protective area of circulation known as the Circle of Willis. Occasionally aneurysms are located more peripherally in the brain and may be associated with infection.

Arteriovenous Malformation (AVM): This is an abnormal collection of blood vessels that rapidly shunts blood into the veins, without an intervening capillary bed. The majority of arteriovenous malformations are discovered before the age of 40. They typically present with hemorrhage and seizures.

Biopsy: Sample of tissue removed for microscopic examination to identify existence or cause of a disease. Biopsy of the brain allows a very small piece of tissue to be removed and analyzed under the microscope. This may be done under CT or MRI guidance, or using a stereotactic biopsy apparatus.

Burr Hole: Small, dime-sized hole made in the skull to drain excess subdural fluid and relieve pressure.

Chiari Malformation: A class of malformations involving the hindbrain (cerebellum). There may be brain stem compression, hydrocephalus, or syringomyelia (fluid cavity within the spinal cord). The most common symptom is headache in the back of the skull. There may also be weakness and trouble with the function of the cranial nerves or nystagmus of the eyes.

Spondylosis: Osteoarthritis of the spine that may cause narrowing of the spine (stenosis).

EPILEPSY/SEIZURE

Epilepsy: A disorder characterized by transient but recurrent disturbances of brain function that may or may not be associated with impairment or loss of consciousness and abnormal movements or behavior.

Seizure: The result of discharges of nerve cells within the brain. They may involve one or both sides of the body. Consciousness may or may not be lost. Seizure may also invoke unusual feelings, smells, and tastes.

Hydrocephalus: Hydrochephalus is caused by increased cerebrospinal fluid within the ventricles of the brain. There are two main categories, communicating and non-communicating. In the communicating variety, all the ventricles are enlarged and the problem lies at the arachnoid granulations through which spinal fluid is normally reabsorbed into the blood. They may be blocked as the result of subarachnoid hemorrhage or infection. In the non-communicating variety, the lateral and third ventricles may be dilated, with a normal 4th ventricle. This may be due to blockage of the aqueduct of Sylvius (which connects the third and fourth ventricles) by a tumor or some other undefined cause.

Shunt: A drainage tube to move cerebrospinal fluid from the ventricles to another part of the body (i.e. abdomen) to decrease ICP (intracranial pressure). A shunt is used to treat hydrocephalus.

Stroke: An interruption of blood supply to the brain. A stroke causes an acute loss of blood flow to the brain, with subsequent death of brain tissue.

Trigeminal Neuralgia: Characterized by electrical shock-like pain that occurs on one side of the face which travels in the distribution of one or more branches of the trigeminal nerve (to the face). It is often triggered by chewing, brushing teeth or touching.

TUMORS

Acoustic Neuromas: A tumor that arises from the superior vestibular nerve, part of one of the cranial nerves that is responsible for balance. It often presents with hearing loss, tinnitus and difficulty with balance. These tumors are benign and grow from the Schwann cells, which are insulating cells. The growth rate is somewhat unpredictable.

Astrocytoma: The most common brain tumor, (there are roughly 12,000 new cases each year), that begins growing in the brain. Astrocytomas are broken down in grading systems into three or four grades. On the four-tier grading system, grade four is the most aggressive and is called a glioblastoma multiforme. These tumors arise from the "insulating cells" of the brain, known as astrocytes, and generally exist without a discrete border.

Chondrosarcoma: A malignant tumor that produces a special type of connective tissue called cartilage. Cartilage is a type of connective tissue that acts as a resistant surface. Cells called chondrocytes produce cartilage. Chondrosarcoma is a malignant growth arising in chondrocytes. There are two types of chondrosarcomas, primary and secondary. Primary chondrosarcomas arise in areas of previously normal bone that are derived from cartilage. Secondary chondrosarcomas are lesions produced from pre-existing cartilage lesions. The chondrosarcoma tumors either produce enlargement or erosion of the area involved. The lesion is classified further as to where the lesion occurs and the grade of the lesion. It is graded from 1 (low-grade) to 3 (high-grade). This classification states that the higher the grade of the tumor, the higher the increased atypical or abnormal cell growth.

Chordoma: Very rare primary bone tumors that can arise at almost any point along the spine. The incidence of chordoma in the general U.S. population is about 8 per 10,000,000 people. They occur somewhat more often in males than females and are rare in African Americans. Under the microscope, chordoma cells appear to be benign, but because of their location, invasive nature, and recurrence rate, the tumors are considered to be malignant.

Choroid Plexus Papilloma: Choroid plexus is tissue located in the spaces inside the brain called ventricles. The choroid plexus makes the fluid that fills the ventricles and surrounds the brain and spinal cord. Pappillomas are warts with irregular surfaces that grow slowly and are less likely to spread into other areas of the brain and spinal cord than anaplastic choroid plexus papillomas, a more rapidly growing variety.

Colloid Cyst: Colloid cysts are nonmalignant tumors that can cause death because of their location. These pathologically benign tumors are almost always found in the third ventricle and can therefore be associated with obstructive hydrocephalus and increased intracranial pressure.

Ependymoma: Tumor which arises from the cells that line the ventricles of the brain and the central canal of the spinal cord. They may spread throughout the cerebrospinal fluid. When located in the brain, they are usually in the fourth ventricle, and may invade the brainstem. In the spine, they may occur in the spinal cord or in the filum terminale (a fibrous band at the lowest aspect of the cord).

Glioma: Tumors of the connective tissue of the brain, including astrocytomas, ependymomas, and oligodendrogliomas. Although complete surgical removal is ideal, it is often not easily accomplished because many of these tumors are infiltrative. Tumors can range in malignancy from relatively benign to extremely aggressive. Often chemotherapy and radiation therapy are used in addition to open surgery.

Glioblastoma: The most aggressive of the gliomas.

Meningioma: A benign tumor which grows slowly within the skull, although a small percentage are more aggressive and fast growing.

Metastasis: The spread of tumors. This usually occurs from other parts of the body to the brain, although brain tumors can spread through the cerebrospinal fluid to other parts of the brain or to the spine. Brain tumors can also spread to the rest of the body, although this is extremely rate.

Oligodendroglioma: A glial tumor made up of cells which insulate neurons in the central nervous system (oligodendrocytes). They may also have a component of astrocytoma mixed in with them. Pure oligodendrogliomas have a better prognosis than mixed tumors.

TRAUMA

Cerebral Edema: Accumulation of excessive fluid in brain. The brain is especially susceptible to injury from edema because it is located within a confined space and cannot expand.

Concussion: Concussion occurs as a result of an injury to the brain. It is described as a trauma-induced change in mental status, with confusion and amnesia and with or without a brief loss of consciousness.

Contusion: A contusion is a bruise. The brain may develop a contusion when small blood vessels under the skin tear or rupture, most often from a blow to the head, a bump, or fall.

Depressed Skull Fracture: Skull fracture that causes a fragment of bone to protrude in toward the brain.

Epidural Hematoma: An epidural hematoma is a blood clot in the brain above the dura mater (tough covering of the brain). They are usually the result of a lacerated artery (usually the superficial temporal artery), and may cause death if there is sufficient mass effect.

Intracerebral Hemorrhage: Bleeding within the brain. There may be many causes. In the absence of trauma, tumors may bleed and cause hemorrhage. Hypertension is known to cause hemorrhages in the basal ganglia, brainstem, and cerebellum. Anticoagulation makes the entire brain more susceptible to hemorrhage. Amyloid angiopathy, also known as congophilic angiopathy, may cause hemorrhage in the brain in older patients.

Intracranial Pressure (ICP): Pressure within the brain that can be measured with a fiber optic pressure monitor, inserted through a small drill hole in the skull. Normal pressure in adults ranges from 10 - 15 mm Hg. It may be elevated due to trauma to the brain, cerebral edema (brain swelling), hemorrhages within the head, hydrocephalus, systemic hypertension, and venous sinus thrombosis.

Subarachnoid Hemorrhage: Bleeding under the arachnoid membrane surrounding the brain, which may indicate a ruptured aneurysm or arteriovenous malformation.

Subdural Hematoma: A subdural hematoma is a blood clot around the surface of the brain, and below the dura mater (tough covering of the brain). When it is old (chronic, over 3 weeks) it can often be removed with a small burr hole, but when fresh (acute, several hours to several days), a craniotomy (opening of the skull) is often needed.