Achilles' heel The ‘Achilles' heel’ is one's weak point, and is named for the only part of the body of the Greek hero Achilles which was vulnerable. The son of King Peleus of Thessaly and the shape-changing nymph Thetis, Achilles is the central character of Homer's great poem, the Iliad.

The weakness of the heel, or more accurately the tendon, of Achilles derives from the story of the unsuccessful attempt by his mother Thetis to make Achilles invulnerable. This seems to be a late addition to his biography, first found in the first-century ad Roman poet Statius. When he was still a child, and against the wishes of Peleus, Thetis held her son by the heel and dipped him in the waters of the river Styx which flows through the underworld; it was in this heel that he was to receive the wound from a poisoned arrow, which killed him. Earlier versions, while omitting this story, have another variation on the theme of the mother desperately trying to preserve her son; Thetis is said to have hidden Achilles at the court of King Lycomedes on Scyros, where he was disguised as a girl. Despite this disguise, he fell in love with the king's daughter — who bore him a son, Neoptolemus — and he was discovered by a party of Greeks sent to find him and take him with the army to Troy. In Homer, Achilles is always aware that he will die young, a premonition heightened by the death of his beloved friend Patroclus; the circumstances of his own death at the hands of the Trojan prince Paris, aided by the god Apollo, are also predicted in Homer.

The Iliad covers just a few weeks of the tenth year of the long period over which the Greek forces laid siege to the city of Troy. It is the ‘Wrath of Achilles’ — his anger at losing his slave concubine, Briseis, to Agamemnon — which forms the theme of the Ilaid. Achilles responds to this loss by sulking in his tent, withdrawing his forces — the Myrmidons — from the combined Greek army. In terms of simple military success, Achilles is ‘the best of the Achaeans’, or Greeks, but he takes the heroic code of honour to extremes. For example, while revenge was a perfectly acceptable part of the code, the Greeks considered that there were limits to what counted as acceptable acts of revenge; yet when he kills the Trojan Hector, Achilles slits Hector's ‘Achilles' tendons’ then uses leather thongs to tie him to his chariot before proceeding to drive round the walls of Troy, watched by an audience of horrified Trojans that includes Hector's mother and father. As a final indignity, Achilles throws what is left of Hector's corpse to the dogs, but the goddess Aphrodite keeps them away. This behaviour is explicitly labelled as ‘shameful’ by Homer, and eventually Hector's remains are returned to the Trojans for proper burial.

In anatomical terms, ‘Achilles' tendon’ survives as an alternative to the formal name of tendo calcaneus for the thick tendon which links the calf muscles to the heel bone (the calcaneum from the Latin for heel). Though very far from weak, the tendon can sometimes be vulnerable to rupture during vigorous sporting activity.

Helen King

See musculo-skeletal system.See also ankle; feet.