Compensatory brow asymmetry: anatomic study and clinical experience.

To obtain detailed information about the interdigitation between the frontalis muscle and the orbicularis oculi muscle, the authors performed an anatomic study involving 9 cadavers (17 specimens). Three types of interdigitation were recognized. Complete interdigitation was noted in 13 specimens, and partial interdigitation in 13 specimens. In one specimen, there was no interdigitation between the frontalis muscle and the orbicularis oculi muscle. Although most of the specimens showed complete interdigitation between the frontalis muscle and the orbicularis oculi muscle, the interdigitation area exhibited architectural heterogeneity. The study findings provide a basis for a better understanding of compensatory eyebrow ptosis. In addition, two cases supporting the theory that compensatory eyebrow asymmetry may resolve when the palpebral ptosis is treated are presented.