Background: This term is from Greek Mythology. According to myth, when Achilles was a baby, his mother dipped him in the river Styx because the waters from this river gave immortality to humans. His mother held him by his heel, so that was the only place on his body not touched by water. From then on, Achilles’ heel was his one area of vulnerability. Eventually, Achilles was killed during the Trojan War when a poisoned arrow struck his heel.