Fig. 2.

Sagittal sections of the upper eyelid. The anterior surface of the frontalis muscle is enveloped by superficial galea (SG, arrowhead) and deep galea (DG, arrows) on its posterior surface. The frontalis muscle (FM) passes through and inserts in the bundles of the orbicularis oculi muscle (OM). (A) Medial section. The FM inserts in the superior border of the eyebrow. The most distal part of the FM is located deep to the procerus muscle (PM) and superficial to the corrugator muscle (CM). (B) Middle section. The FM inserts in the superior border of the eyebrow. (C) Lateral section (the FM inserts about 0.5 cm below the superior border of the eyebrow). OS, orbital septum; PAF, pre-aponeurotic fat; POF, pre-orbicularis fascia.