once when i was visiting a chiropractor
i was getting on a table to get x-rays
when (apparently due to the back pain-
which was why i was at the chiro.) I
passed out...i had bumped my head on
the x-ray machine and was immediately
referred to a clinic to see an m.d.
as she thought i may need stitches in
my head.

another time while during that same
period of time, i conked out in a
restaurant rest room. the last thing
i remember was seeing car head lights
flash in my eyes as a vehicle came out
of a parking lot across from where I
was sitting in the restaurant. I have
heard that some people are prone to
such reactions after seeing strobe
lights. When i worked with disabled
students, we had to be very careful
when we took them to the science
museum where there were strobe lights.

fainting is known as Syncope, syncopy
or syncopal episode.
http://medical-dictionary.thefreedictionary.com/Syncopy