Overview:  A brain shunt is a narrow piece of tubing that is inserted into the brain through a fluid-filled ventricle. The tubing is then passed under the skin into another area of the body (typically most occurring in the abdomen). Normally, the shunt tubing may be placed into one of the chambers of the heart or the lining of the lungs. This tubing is relieves pressure on the brain by draining the extra fluid in the brain ventricles.