Achilles' heel

In Greek mythology, when Achilles was an infant, it was prophesized that he would perish at a young age. To prevent his death, his mother Thetis took Achilles to the River Styx, which was supposed to offer powers of invulnerability, and dipped his body into the water; however, as Thetis held Achilles by the heel, his heel was not washed over by the water of the magical river. Achilles grew up to be a man of war who survived many great battles.

Oil painting (c. 1625) by Peter Paul Rubens of the goddess Thetis dipping her son Achilles in the River Styx, which runs through Hades. In the background, the ferryman Charon rows the dead across the river in his boat.

Although the death of Achilles is predicted by Hector in Homer’s Iliad, it does not actually occur in the Iliad, but is described in later Greek and Roman poetry and drama[3] concerning events after the Iliad, later in the Trojan War. In the myths surrounding the war, Achilles was said to have died from a wound to his heel,[4][5] ankle,[6] or torso,[4] which was the result of an arrow—possibly poisoned—shot by Paris.[7]

Classical myths attribute Achilles' invulnerability to his mother Thetis having treated him with ambrosia and burned away his mortality in the hearth fire except on the heel, by which she held him. Peleus, his father, discovered the treatment and was alarmed to see Thetis holding the baby in the flames, which offended him and made her leave the treatment incomplete.[8] According to a myth arising later, his mother had dipped the infant Achilles in the river Styx, holding onto him by his heel, and he became invulnerable where the waters touched him—that is, everywhere except the areas of his heel that were covered by her thumb and forefinger.[9]

The oldest-known written record of the tendon being named for Achilles is in 1693 by the Flemish/Dutch anatomist Philip Verheyen. In his widely used text Corporis Humani Anatomia he described the tendon's location and said that it was commonly called "the cord of Achilles."[10][11] As an expression meaning "area of weakness, vulnerable spot," the use of "Achilles heel" dates only to 1840, with implied use in Samuel Taylor Coleridge's "Ireland, that vulnerable heel of the British Achilles!" from 1810 (Oxford English Dictionary).[12]

The large and prominent tendon of the gastrocnemius, soleus, and plantaris muscles of the calf is called the tendo achilleus or Achilles tendon. This is commonly associated with the site of Achilles' death wound. Tendons are avascular, so such an injury is unlikely to be fatal; however, the myth has the arrow poisoned with the blood of the Lernaean Hydra.

A more likely anatomical basis for Achilles' death, assuming an unpoisoned dart, would have been an injury to his posterior tibial artery behind the medial malleolus, in between the tendons of the flexor digitorum longus and the posterior tibial vein. This area could also have been included in Thetis's grip.

Look up Achilles heel in Wiktionary, the free dictionary.

• Achilles tendon – Tendon at the back of the lower leg
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• Duryodhana in the Mahabharatha
• Esfandiyār in the Shahnameh
• Kryptonite – Fictional material in Superman stories
• Siegfried – Fictional character in Germanic and Norse mythology in the Nibelungenlied
• Single point of failure – A part of a system that, if it fails, will stop the entire system from working
• Squatting position – resting posture where the weight of the body is on the feet but the knees and hips are bent