History of Medical Symbols

Emergency care in the field has been rendered in different forms since history began to be recorded. The Bible includes the Old Testament account of the Israelites being bitten by poisonous snakes. (Numbers 21:6-9) God commanded Moses to make a bronze snake and mount it on a pole. Then, anyone bitten must only look at the bronze snake and they would be healed.

Some credit this account as the basis for the United States' EMS symbol, the Star of Life, where a single snake wrapped around a pole is seen in the center of a blue, six-barred cross. The six sides represent the six essential functions of EMS:

1. Detection
2. Reporting
3. Response
4. On Scene Care
5. Care in Transit
6. Transfer to Definitive Care

However, others attribute this snake symbol to the Greek mythological figure Asclepius, the son of Apollo. Asclepius was trained as a healer by Cheron the Centaur. Once, when he consulted a serpent about a very difficult patient, the snake coiled around his staff in order to speak with him as an equal. Later, Asclepius was slewn by Zeus, but because of his remarkable healing ability, people began to worship in his temples. Eventually, Zeus brought him back to life as a god.

The caduceus is a winged staff with two snakes wrapped around it. It was an ancient astrological symbol of commerce and is associated with the Greek god Hermes, the messenger for the gods, conductor of the dead and protector of merchants and thieves. It was originally a herald's staff, sometimes with wings, with two white ribbons attached. The ribbons eventually evolved into snakes.

In some cases, depictions of the Greek kerykeion can be radically different from that of the traditional caduceus (as in the picture at right). These representations will feature the two snakes atop the wand (rod), crossed to create a circle with the heads of the snakes resembling horns. In this form, it looks remarkably similar to the symbol for the planet Mercury — while Mercury the god is the Roman name for Hermes, who carries the kerykeion, or caduceus. The Greek messenger goddess Iris also carried the caduceus. The basic power of the Caduceus is the primal power to heal or harm.

In the seventh century, the caduceus came to be associated with a precursor of medicine, based on the Hermetic astrological principles of using the planets and stars to heal the sick. As a symbol for medicine, the caduceus is often used interchangeably with the Rod of Asclepius (single snake, no wings), although learned opinion prefers the Rod of Asclepius, reserving the caduceus for representing commerce. Historically, the two astrological symbols had distinct meanings in alchemical and astrological principles.

Some medical organizations join the serpents of the caduceus with rungs to suggest a DNA double-helix. It has also been suggested that the caduceus derives from the treatment for Guinea Worm disease, which requires sufferers to pull the worms out of their legs by slowly, over a period of many days, winding the worm around a stick which is twisted a little more each day to draw the worm out. It is also said that doctors would wrap the extruding parasite around a stick over the course of weeks or months, and the result was worn as an indicator of the doctor's competence, although this suggestion seems to be more represented by the Rod of Asclepius.

The symbol's origins are thought to date to as early as 2600 BC in Mesopotamia, and there are several references to a caduceus-like symbol in the Bible, namely in Numbers 21:4–9, and 2 Kings 18:4. During the Exodus, Moses was instructed by God to fashion a pole upon which he was to position a serpent made of bronze; when looked upon, this Nehushtan, as it was called in Hebrew, would spare the lives of the Israelites stricken by venomous snakebites. The intent was that people would look upward and be reminded to pray to God, but eventually the meaning was forgotten and this symbol was apparently worshiped by the Hebrew people until the reign of Hezekiah as described in 2 Kings 18:4.