Jeod implies that the city was much bigger than Teirm, as large as Dras-Leona and Gil'ead. It was so isolated by the Spine that it became a peculiar place, full of strange customs and superstitions. Brom, for instance, always knocked three times on a doorframe before entering or leaving a room. But during his training, he forgot his superstitions as a result of other Riders making fun of him.
In Inheritance Eragon goes to Kuasta to assert the Varden's authority there and they give in easily, unlike Teirm.
It is interesting the note that both Eragon and Brom come from isolated towns in and near the Spine. Heslant the Monk, the author of Dominance of Fate, also was part of a sect that originated in Kuasta.