Background: The motor innervation of the lower orbicularis oculi has not been clearly established. There is a discrepancy between anatomical descriptions and clinical outcomes of the motor innervation of the pretarsal orbicularis oculi muscle. Therefore, the purposes of this study were to identify every motor and sensory nerve of the lower eyelid, and to reveal the detailed motor nerve pathways toward the medial canthal area. Methods: Fresh cadaver dissections were performed on 50 hemifaces under a surgical microscope. Submuscular and intramuscular nerves of the lower eyelid were identified, and the pathways of facial nerves that ran toward the medial canthus were traced. Results: Vertical submuscular nerves at the lower eyelid originated from the infraorbital foramen, indicating that all were sensory nerves. The zygomatic branch of the facial nerve traveled obliquely through the anterior cheek and supplied the orbicularis oculi of the lower eyelid and the medial portion of the upper eyelid. Its route was defined as a clinically useful line, the medial orbicularis motor line. In addition, the nerve innervating the pretarsal orbicularis oculi arose at the superomedial preseptal area and extended horizontally and laterally. Interestingly, the angular nerve appeared not to innervate the palpebral orbicularis oculi. Conclusions: In the lower eyelid, the vertical sensory and the oblique motor nerve supplies are independent and clearly distinguished in aspect of their own routes. The medial orbicularis motor line represents the motor route to the medial portion of the orbicularis oculi. These results might provide valuable knowledge about surgical anatomy for safe lower blepharoplasty with or without midface lift.

The aim of this study is to elucidate anatomic detail of the lateral canthal area relating to lateral canthoplasty. Thirty-three hemifaces of 22 Korean adult fresh cadavers were used. Thirty-one specimens were used for tension measurement and 2 for histologic study. There were 3 components of the lateral canthal area under the skin; lateral palpebral raphe (LPR), superficial lateral palpebral ligament (SLPL), and deep lateral palpebral ligament (DLPL). Lateral ends of superior and inferior orbicularis oculi muscles interlaced at the lateral commissure and formed LPR. SLPL extended from the lateral ends of tarsal plate to the periosteum of lateral orbital rim. Its transverse length was 9.4 ± 2.6 mm and vertical width was 3.6 ± 1.3 mm. DLPL extended from the lateral ends of tarsal plate deep to the origin of SLPL to Whitnall's tubercle on zygomatic bone inside the orbital margin. It is located deeper than SLPL. Its transverse length was 7.3 ± 1.6 mm and its vertical width was 9.0 ± 1.6 mm. Tensile strength of DLPL was 73.2 ± 26.8 N and stronger significantly than SLPL (30.0 ± 17.3 N). Tensile strength of LPR was 12.2 ± 8.0 N and weaker significantly than SLPL and DLPL. A detailed understanding of 3 layered structures (LPR, SLPL, and DLPL) at lateral canthal area is conducive to performing lateral canthoplasty.

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. Twenty-one 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.

Natural looking double fold is an essential and aesthetically pleasing masterpiece in Asian blepharoplasty. This study aims to emphasize the 3 skin zone concept in the Asian upper blepharoplasty. The authors examined the anterior lamella of each skin zone microscopically by performing 31 double-eyelid surgeries and 11 infrabrow lifts. Characteristics of dermal components, subcutaneous tissue, and outer fascia of OOM (OFOOM) at each skin zone were documented. The authors evaluated the vertical scales of each skin zone in young and aged Asian patients who visited the first author's clinic for the primary or secondary upper blepharoplasty with ×3.5 magnifying surgical loupe. The thickness of OOM had no difference among zones 1, 2, and 3. The skin and subdermal tissue had varying characteristics according to its skin zone. At zone 1, it seemed that only thin skin was on the OOM. The anterior lamella of zone 2 seemed to consist of skin, white fascia (OFOOM) including a venous network, and OOM in a gross field. At zone 3, thick skin, thick subcutaneous fatty layer, and OOM were magnified. The OFOOM of zone 3 was not significantly identified due to a sticky adherence with OOM. At the point of vertical scales of skin zone, good eyelids have lower zone 3 ratio and higher zones 1 and 2 ratio with qualified topographic condition. The authors classified the Asian upper eyelid as with 3 skin zones. Based on its anatomical investigation, the authors can afford anthropometric data and supplemental theory for the creation of aesthetic folds.