which finger points?

which finger of the yad יד points?

On a poster for the muse­um show The Pre­cious Lega­cy; Juda­ic Trea­sures from the Czechoslo­vak State Col­lec­tions you can see 15 “Yads.”

Only one of these is left-hand­ed (which does not sur­prise me). Of the remain­ing right-hand­ed ones (made, pri­mar­i­ly, of sil­ver and wood with a lit­tle ivory and oth­er mate­ri­als) the hand is curled into a fist and the thumb points. Yet more odd, in anoth­er, the point­er is made of red coral (?) and the thumb (which serves as the point­er) is tucked under the index fin­ger (as in the Signed Eng­lish Alpha­bet “T”).

Has any­one stud­ied con­ven­tions for point­ers? Does a data­base of them exist in any muse­um? If not, where would we begin to set one up?