Cutaneous innervation of lower eyelid

The loss of skin sensation or numbness after lower blepharoplasty is not uncommon. The aim of this study is to elucidate the infraorbital nerve (ION) and zygomaticofacial nerve (ZFN) in detail. Twentyone hemifaces of 14 fresh Korean adult cadavers were dissected. Infraorbital nerve and ZFN came out of infraorbital foramen and zygomaticofacial foramen. They ran along superficial to the periosteum within and beneath the epimysium of the orbicularis oculi muscle and then through orbicularis oculi muscle perpendicularly and distributed to the skin. The distal branch approached to the lower border of the tarsal plate. Most terminal branches (93.8%) of ION were distributed medial to the lateral canthus. Only a few branches (6.2%) were lateral to the lateral canthus. Most (99.4%) terminal branches of ZFN were distributed lateral to the lateral canthus. Very few (0.6%) branches were medial to the lateral canthus. We conclude that the skin-muscle flap infringes less than the skin flap on the terminal branches of ION and ZFN in exposure of the orbital floor as well as in lower blepharoplasty.