The transition of the lips where the outer skinner and inner mucous membrane meet is called the _________

I looked it up and from what I read I believe it is the gingivae. Would that be correct.

Thank you

I looked up gingivae, but got the equivalent to the gums.

Since this is not my area of expertise, I searched Google under various key words, finally going to "mouth anatomy membranes", to get these possible sources:

http://www.emory.edu/ANATOMY/AnatomyManual/nose.html
http://members.tripod.com/dentdoctor/Oral_Anatomy/index2.html
http://en.wikipedia.org/wiki/Lip
(Broken Link Removed)
http://yourtotalhealth.ivillage.com/oral-dental-anatomy.html

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

I hope this helps. Thanks for asking.