Where does “viimekätinen” come from?

viimekätinen (Finnish) comes from Finnish -kätinen, from Finnish käsi, from Finnish kahdeksan, from Proto-Finnic kakteksa, from Proto-Finnic kakci, from Proto-Uralic *kakta.

Ancestry of “viimekätinen”, step by step

Step	Language	Word	Meaning
1	Finnish	-kätinen	-handed
2	Finnish	käsi	hand; arm
3	Finnish	kahdeksan	eight
4	Proto-Finnic	kakteksa	eight
5	Proto-Finnic	kakci	two
6	Proto-Uralic	*kakta	—

Every word from Proto-Uralic *kakta →Every word from Proto-Finnic kakci →Every word from Proto-Finnic kakteksa →