Coordinate System

We use the following standard orientation to display data:

• +x points in right direction (sometimes a bubble or some other artifact in the data may indicate left and right)

• +y points in anterior direction

• +z points in superior direction

• -x points in left direction (sometimes a bubble or some other artifact in the data may indicate left and right)

• -y points in posterior direction

• -z points in inferior direction

As the explanation is a bit tricky, here another try: If you look from the front (anterior) your position is at +y and you look into -y direction.

See Wikipedia for more information on anatomical location terms.