Eyelid anatomy

Seen here are the major muscles of eyelid opening and closure. The levator palpebrae, which is innervated by the oculomotor nerve, inserts on the tarsus via the levator aponeurosis and directly on the skin of the upper eyelid. The superior tarsal muscle (also known as Muller's muscle, which is innervated by oculosympathetic fibers) originates from the levator aponeurosis and inserts on the tarsus. The orbicularis oculi (OO) is innervated by the facial nerve. It is made up of two portions: one contained within the eyelid itself (palpebral portion) and one located outside the eyelid surrounding the orbit (orbital portion). The palpebral portion of the OO can be further subdivided into preseptal and pretarsal components based on its anatomic location relative to the tarsus (Modified with permission from: Miller, N. et al. Eds. Walsh and Hoyt's Clinical Neuro-Ophthalmology. 6th Ed. Figures 24.2 and 24.5. Available at: Neuro-Ophthalmology Virtual Education Library. Accessed: June 20, 2017