A sample of suspicious or abnormal tissue or sample cells taken from the body in order to undergo examination to determine the presence or extent of a disease or disease process.

A harmless medicine or procedure -which has no physiological effect- that is prescribed for its positive psychological effects on patients.

Also known as a sleep study.  It is a test performed to diagnose sleep disorders- recording brain waves, oxygen levels, heart rate, breathing; as well as eye and leg movement.

Study in which the subjects are selected on the bases of factors that are to be observed for possible effects on some result.

Imagining technique that utilizes electromagnetic radiation to visualize the internal structure of the body; X-rays.

A method of Magnetic Resonance Imaging (MRI) that allows for scanning of the patients in the positions they experience their problems— standing, bending, sitting, leaning, as well as the standard lying down. With Chiari this can be an invaluable tool, much better than the standard supine (horizontal) MRI, because it allows images that include the effects gravity is having on herniation (tonsillar ectopia). Additionally, it can make certain comorbid conditions, such as Tethered Cord, more visible.

Imagining technique which uses high- frequency sound waves to create pictures of organs and other internal structures.

Computer-processed arrangements of multiple X-ray images, all taken from different angles to produce virtual “slices” of specific areas of the body.

A study where an individual person, family, or group is observed over a particular period of time.