It's the ridge directly in front of the opening where the mandibular nerve enters the lower jaw. It's marked "Mandibular for.(amen)" in this drawing from Gray's:
42 posted on 07/14/2009 6:36:11 AM PDT by CholeraJoe
(So close to Postal)
43 posted on 07/14/2009 6:52:12 AM PDT by SunkenCiv
(https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)