The nasolabial flap. Axial or random?

Considerable confusion exists regarding the nature of the blood supply of the inferiorly based nasolabial flap. This report seeks to clarify the situation. Anatomic dissections were performed on 12 cadaveric specimens and microangiography on six others. We confirmed that the facial artery passes deep to the facial mimetic muscles and is not normally included within the flap. Although the vasculature of the flap is technically random, the small vessels of the subdermal plexus are generally oriented along its long axis giving it a "degree of axiality." We believe this vascular orientation is responsible for the flap's reliability.