Hemorrhoids are classified into two general categories: internal and external. Internal hemorrhoids lie far enough inside the rectum that you can't see or feel them. They don't usually hurt because there are few pain-sensing nerves in the rectum. Bleeding may be the only sign that they are there. Sometimes internal hemorrhoids prolapse, or enlarge and protrude outside the anal sphincter.
Cerebrospinal fluid (CSF) collection is a test to look at the fluid that surrounds the brain and spinal cord. CSF acts as a cushion, protecting the brain and spine from injury. The fluid is normally clear. The test is also used to measure pressure in the spinal fluid. See also: CSF culture.
Hydrocephalus is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain, which may cause increased intracranial pressure (ICP) inside the skull.erebrospinal fluid (CSF) is a clear, colorless body fluid found in the brain and spine.