Abscess, perianal

Abscess, perianal: An abscess ( a local accumulation of pus) that forms next to the anus (the opening of the rectum to the outside of the body) causing tender swelling in that area and pain on defecation. Peri- is a prefix borrowed from the Greek that means "around or about." Pericardial is around the heart. Perinatal is around birth. And periumbilical is around the umbilicus (the belly button). Peri- is a useful prefix in anatomy much employed in medicine. Pericardial fluid is fluid around the heart. Periaortic lymph nodes are lymph glands around the aorta. And a perianal abscess is, as noted, an abscess adjacent to the anus.