Direction and Orientation of Transfer:
Envelope flap (F/EN): Retracted away from a horizontal incision; there is no vertical incision
Advancement (or sliding) flap (F/AD): Carried to its new position by a sliding technique in a direction away from its base
Rotation flap (F/RO): A pedicle flap that is rotated into a defect on a fulcrum point
Transposition flap (F/TR): Flap that combines the features of an advancement flap and a rotation flap
Hinged flap (F/HI): Folded on its pedicle as though the pedicle was a hinge; also called a turnover or overlapping flap
Apically positioned flap (F/AP): Moved apical to its original location
Coronally positioned flap (F/CO): Moved coronal to its original location
Mesiodistally or distomesially positioned flap: Moved distal or mesial to its original location along the dental arch; also called a laterally positioned flap (F/LA)