BACKGROUND Accessory levator muscle slips may be associated with congenital eyelid retraction or blepharoptosis. Nevertheless, congenital retraction of the upper eyelid is a poorly defined entity about which little is known. Because of the clinical importance of the accessory levator muscle slip of the levator palpebrae superioris muscle, this study aimed to describe the morphological appearance of this variation in human adult orbits. METHODS This study was undertaken in 60 orbits of 30 embalmed adult human cadavers, 17 men and 13 women, between the ages of 38 and 87 years at death. All cadavers were embalmed in 4% formalin solution. RESULTS Three accessory levator muscle slips of the levator palpebrae superioris muscle were identified. One of these arose laterally from the origin of the levator palpebrae superioris muscle. At its anterior end, it divided into two parts, the main superior and a smaller inferior accessory. The second had an accessory levator fibromuscular slip. It arose medially from the origin of the levator palpebrae superioris and lost its muscular character after a short course. The third arose from the origin of the levator palpebrae superioris as a thin flat muscle. CONCLUSIONS Although many variations of the levator palpebrae superioris muscle have been reported in fetuses, investigation and demonstration of these may be more important in children and adults for ophthalmic surgery. We believe that detailed knowledge regarding the morphological appearance of an accessory levator muscle slip of the levator palpebrae superioris muscle may be useful for successful outcomes in ophthalmic surgery.