Quite irritating thing about Trac Wiki is, it has no back link.
A workaround for the same is installing external macros from trac-hacks.org.
You could use following two macros
http://trac-hacks.org/wiki/BackLinksMacro (Adds textual info at the top of page)
http://trac-hacks.org/wiki/BackLinksMenuMacro (Adds a menu to top RHS like pageoutline macro)
Download the zip from the site. Extract it to some temp location.
Check your trac version(click on "about trac" link).
Copy the BackLinksMenu.py/ BackLinks.5.py(rename to BackLinks.py) from the correct version folder to /usr/share/trac/wiki-macros/
Restart apache and you are done.