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.
Also known as: cerebrospinal fluid (CSF) leak. Cerebrospinal fluid (CSF) rhinorrhea is the medical term for a rare condition in which the fluid that normally cushions the brain and spinal cord, cerebrospinal fluid, runs from the nose. For this to happen an abnormal path between the subarachnoid space of the brain and nasal/sinus cavities is inadvertently created.