A leger line (sometimes spelled ledger line) is a tool of musical notation to express notes that do not fall on the regular lines or spaces of the musical staff. A short line (slightly longer than the note) is drawn parallel to the lines on the staff, corresponding to where the staff line would be if the note were in range (see Figure 1).
Notes on more than three or four leger lines off the staff are usually considered too hard to read; this is usually handled by using 8va notation or switching clefs.
Figure 1. leger lines above the staff, using eighth notes. The lines on the right would usually be considered too far off the staff and would be written in a different clef or with 8va notation.
