The etymology blog of Anatoly Liberman on the Oxford University Press blog is always a treat to read, and so it is with this week's installment dealing with the etymology of the English words feel and finger. This passage is especially interesting:
Some historical linguists connect finger with the numeral five. In the past, five had the consonant n in the middle (German fünf still has it, and Gothic for “five” was fimf). However, the path from finf or fimf to fingr “does not run smooth.” To begin with, it is hard to understand where the suffix –r came from (it is indeed a suffix, not an ending: see fingraz, that is, fingr-az above).
Of course this stuff has parallels in Eldarin - but Tolkien (elegantly, I think) cut through the "Gordian knot" and made the link between finger and five quite straightforward. Nice one, Professor.