The bends or twists in the disk component of M31 (that is, position angle changes) are well shown in this Burrell Schmidt image by P.Guhathakurta
(for the larger original, see his website:
http://www.ucolick.org/~raja/
)
There is more than one change in P.A., as we move outwards along the major axis of this galaxy.
[For some reason the above link does not work, but typing in the URL does.]