Orbicularis oculi muscle The orbicularis oculi muscle is a broad, flat muscle that encircles the orbit, thus forming a sphincter around each of the eye sockets. It may be divided into three portions: Orbital part, palpebral part, and lacrimal part. Orbicularis oculi muscle - Orbital part Origin: Frontal process of the maxilla, lacrimal bone, nasal portion of the frontal bone, medial palpebral ligament and lacrimal sac Insertion: Lateral palpebral ligament Innervation: Facial nerve (VII) Action: