Sinistromanual

[T]he artist, probably for the sake of symmetry, makes one right-handed and the other left-handed. The alternative, of course, is that the latter actually was a sinistromanual player of note [of the game of t'ou hu or pitch-pot] and was thus intentionally represented. In any event, we have in this relief a very early Chinese illustration of this phenomenon.

Source: wiktionary

In a world where most major medical maladies are readily treated, numerous minor medical conditions which today escape our notice will rise up from obscurity and present themselves annoyingly to our conscious minds, demanding attention. These conditions may be of several kinds. […] Third is minor physical or functional flaws, such as […] handedness (currently ~90% dextromanual, ~10% sinistromanual), […]

Source: wiktionary

"Precisely. Whoever killed this young girl was sinistromanual, an unusual state in this day." / "My murderer was left-handed? That is most unusual, I agree. How do you come to that finding?"

Source: wiktionary

There are other cautions to be emphasized relating to the acquirement of dextrality by the savage: Nearly all the actions which we now call right-handed were in primeval times to him unknown. […] [T]he modern gun and revolver had not been devised. The bow and arrow, the spear, boomerang, club, etc., could be used as well with the left hand by the sinistromanual.

Source: wiktionary