It has a curved origin from the medial orbital margin, being attached to the superomedial orbital margin, maxillary process of the frontal bone, the medial palpebral ligament, the frontal process of the maxilla, and the inferomedial orbital margin. Fibers from the medial origin sweep around the orbital margin in a horseshoe fashion. The muscle fibers extend superiorly to intermix with the frontalis and corrugator supercilii muscles and laterally to cover the superficial temporal fascia. Functionally, the orbital portion of the muscle is used in forced eyelid closure, and hence also acts as a brow depressor. The superomedial portion of each orbicularis muscle also is referred to as the depressor supercilii muscle.
Innervation is from branches of the facial nerve.
The nerves are horizontally orientated and innervate the muscle from the undersurface. The ROOF frequently continues inferiorly over the superior orbital rim, to overlie the orbital septum. The function of this tissue may be to enhance eyebrow mobility. The subgaleal space is used as a plane of dissection in forehead surgery. Connective tissue lies between the galea and the periosteum, which can be easily divided with a semisharp dissector.