Positions of the arms. Although the positions of the feet are standard in all methods, the positions of the arms are not, each method having its own set of arm positions. The Cecchetti method has five standard positions with a derivative of the fourth position and two derivatives of the fifth position. The French School has a preparatory position and five standard positions. These positions are used in some Russian schools. The Russian School (Vaganova) has a preparatory position and three standard positions of the arms.
These are numbered, as are the positions of the feet, but the numbering varies from one school to the next. The four basic positions are: (a) arms down and a little in front of the legs (called bras bas ["low arms"],) (b) arms to the side, (c) arms forward (at about the height of the bottom of the breastbone), (d) arms overhead. In all positions, the arms are gently curved.
When the arms are forward, they are held as if embracing a large barrel (one large enough that the hands can't meet). The forward position is sometimes known as the "gateway," because in many port de bras, the arms pass through the gateway on the way to a higher position. The position with the arms to the side is universally known as second position. In this position, they are curved forward of the body, as if embracing a large cylinder perhaps 8 feet (2.5 m) in diameter. Arms overhead are sometimes called en couronne ("like a crown"). In this position, they should be far enough forward that you can just make out the little fingers (by peripheral vision) when looking straight ahead.
Numbering: (a) (arms down) is bras au repos according to the French school, "preparatory position" according to the Russian school, and first position according to Cecchetti. (b) (arms to the side) is universally known as second position. (c) (arms in front) is first position according to the French and Russians and fifth position en avant ["in front"] according to Cecchetti. (d) (arms overhead) is fifth position for the French, third position for the Russians, and fifth position en haut ["up high"] for Cecchetti. Source: Vance's Fantastic - BALLET DICTIONARY