However, the upper ring-finger key can be used, typically for B2 and B3, in place of the top thumb key on the front of the boot joint; this key comes from the oboe, and some bassoons do not have it because the thumb fingering is practically universal. The smallest finger operates three keys.
The upper ring-finger key on the front of the boot joint can be substituted for the top thumb key, which originates from the oboe. Some bassoons do not have this key due to universal thumb fingering. The smallest finger operates three keys.