Mentalis
The mental tubercles on either side of mental protruberance(in midline) gives origin to the mentalis muscle. Above the mentalis origin, the incisivus muscle takes origin from small fossa called the incisivus fossa.
Complete reflection of mentalis muscle for the purpose of extension of a subperiosteal implant or symphyseal intraoral graft should be avoided as it may result in "witch's chin" probably caused by the failure of muscle reattachment.