(details from "Johannes or Johan Kleberger"), 1526 Albrecht Durer (1471-1528) Kunshistorisches Museum, Vienna, Austria

The filtrum or philtrum (midline groove on the upper lip) is a part of the "pro-labium" related to outline and indentation in the middle of the Cupid's bow or other edge of the vermillion or mucosa of the lip. The ancients placed perfumes in the philtrum to filter out or deodorize the stench then often permeating streets with a cloacal canal or flowing sewage. A "flat" upper lip, a lack of a philtrum, a thin upper vermillion are more common among individuals exposed to alcohol before their birth. In conjunction with other signs, clinicians often can diagnose Fetal Alcohol Spectrum Disorders or Syndrome (FASD).