The effect of a Le Fort I incision on nose and upper lip dynamics: Unraveling the mystery of the “Le Fort I lip”

All the components of the deep layer of the modiolus alae nasi (transverse part of the nasalis muscle and the myrtiformis muscle) and the deep layer of the midface musculature (levator anguli oris muscle) were transected by the Le Fort I incision. After performing the incision, the majority of the depressor septi nasi is intact. Further, the superficial layer of the midface musculature is intact but it loses tension because of its connection to the deep layer. This study suggests the importance of correctly suturing the deep muscular layers to maintain the 3-dimensional facial contour. Moreover, in this cadaver study, we attempt to predict the functional consequences on the impairment of facial mimics related to the Le Fort I incision.