Culdocentesis

Culdocentesis: The puncture and aspiration (withdrawal) of fluid from the cul-de-sac, the rectouterine pouch (the pouch of Douglas), an extension of the peritoneal cavity between the rectum and back wall of the uterus.

The word "culdocentesis" is derived from "cul-de-sac" which is a blind pouch or cavity that is closed at one end and, in a more specific sense, refers to the rectouterine pouch. In French, "cul-de-sac" literally is "bottom of (a) sack." As early as the 13th century, a cul-de-sac was a dead-end street (or a dead-end way), a blind alley.

A "centesis" is a puncture (the Greek "kentesis" = puncture), as in: abdominocentesis (am abdominal tap), amniocentesis (an amniotic fluid tap), etc. Thus, the composite word "culdocentesis" = a tap of the cul-de-sac.