Gamma knife:  Equipment that precisely delivers a concentrated dose of radiation to a predetermined target using gamma rays. More about stereotactic radiosurgery.
Glasgow coma scale (GCS):  The most widely used system of classifying the severity of head injuries or other neurologic diseases.
Glasgow outcome scale:  A widely used system of classifying outcome after head injury or other neurologic diseases.
Glia (glial cells):  The major support cells of the brain. These cells are involved in the nutrition and maintenance of the nerve cells.
Glioblastoma:  A rapidly growing tumor composed of primitive glial cells, mainly arising from astrocytes. More about glioblastoma multiforme (GBM).
Glioma:  A tumor formed by glial cells.
Globus pallidus:  Part of the basal ganglia, which are brain cells that lie deep in the brain.
Greater occipital nerve:  A branch of the second cervical spinal nerve that innervates the middle portion of the occipital area (at the back of the skull) of the scalp.

Weill Cornell Medicine Neurological Surgery 525 East 68 Street, Box 99 New York, NY 10065 Phone: 866-426-7787