Orientation (sign language) in the context of "Nonmanual feature"

A nonmanual feature, also sometimes called nonmanual signal or sign language expression, is any feature of a sign language aside from those produced using the hands, including body postures and facial expressions. Nonmanual features are necessary components of the grammars of sign languages, in the same way that manual features are. Nonmanual features serve many functions, including negation, grammatical mood, and some functions often served by intonation in spoken languages. Expression is one of five components of a sign, along with handshape (DEZ), orientation (ORI), location (TAB), and movement (SIG). A major component of expression is mouthing. However, not all signs have an inherent expression.