Thin square bracket for orchestra scores
Large orchestral scores make use of three types of brackets to group staves:
- Thick square bracket (labeled "bracket" in MuseScore)
- Curly bracket or brace (labeled "accolade" in MuseScore)
- Thin square bracket (not present in MuseScore)
Thin square brackets are recommended for grouping two or more of the same instrument (plus a few other instances). The thin square brackets should match the line thickness of the staff lines.
Attached is a screenshot of the Chamber Orchestra template in MuseScore 1.3 (on the right side) and the equivalent score layout in Finale (on the left side).