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.
Cerebrospinal fluid (CSF) is a clear, watery liquid that flows around the brain and spinal cord, surrounding and protecting them. A CSF analysis is a group of tests that evaluate substances in CSF in order to diagnose conditions affecting the brain and spinal cord (central nervous system). sample of cerebrospinal fluid (CSF) is collected by a health practitioner from the lower back using a procedure called a lumbar puncture or spinal tap. Often, three or more separate tubes of CSF are collected, and multiple tests may be run on the different samples.