In a comment on this answer, luchonacho comments that tenus is a preposition taking the genitive; this seemed odd to me, since I'd never considered tenus anything akin to a preposition.
Tenus seems to be a "postposition", in that it comes after a noun. But how does this work, syntactically? Are "postpositions" a proper category in Latin, like prepositions are? If not, what are they?