Supination

Overview
Supination is the rotation of either the forearm or foot. Supination in the forearm occurs when the palm faces anteriorly, or faces up (when the arms are unbent and at the sides). Supination in the foot occurs when a person appears "bow-legged" with their weight supported primarily on the anterior of their feet.

The hand is supine (facing anteriorly) in the anatomical position. This action is performed by the Biceps brachii and the Supinator muscle.

Supination is the opposite of pronation.

History
Originally, supination of the forearm was attributed as a function of the brachioradialis muscle. However, the original idea of the biceps acting as a supinator was something hypothesised by Leonardo da Vinci, in a series of annotated drawings made between 1505 and 1510 (referred to as his Milanese period); in which the principle of the biceps as a supinator, as well as its role as a flexor to the elbow was devised. However, this function remained undiscovered by the medical community as Da Vinci was not regarded as a teacher of anatomy, nor were his results publicly released.

It was not until 1713, that this movement was re-discovered by William Cheselden, and subsequently recorded for the medical community, being rewritten several times by different authors wishing to present information to different audiences. Nevertheless, the most notable recent expansion upon Cheselden's recordings was achieved by Guillaume Duchenne in 1867 in a journal named Physiology of Motion, something which to this day is one of the major references on supination action of the biceps brachii.