I Have In The Past Been Told I Have TMJ

I have in the past been told I have TMJ and on another occassion, I have been told I possibly have a dislocated jaw. Both suggestions by dentists more than 6 years ago. I suspect a possible skull fracture from a concussion related trauma dating back more than 36 years ago. I have been told I must first receive a diagnosis from a "general" neurologist however, med search engines do NOT differentiate. Please advise