Urasmaa vs. Uurusmaa

Following Kacc. verse 274 I find the example:
  "Urasmaa jaato putto."
This strikes me as a bit odd.

(1) Could "Ura" (chest) here be confused with "Uuru" (thigh)?  All the
editions I've seen render it "Ura" consistently.
(2) Is this a reference to a specific Hindu myth I am unaware of, e.g., how
the various castes were born from the various parts of a divine body?  Or,
perhaps, the supernatural birth of some god/hero?
(3) Is this simply a "normal usage" in Pali, i.e., to speak of being "born
from the heart" of one's mother, in an abstract sense?

I couldn't find any comparable phrase in the Suttapi.taka using the usual
computer search.

E.M.


--
A saying of the Buddha from http://metta.lk/
View Streaming Dhamma Video http://dharmavahini.tv/
Behold this beautiful body, a mass of sores, a heaped-up (lump), diseased,
much thought of, in which nothing lasts, nothing persists.
Random Dhammapada Verse 147