An anatomical study of the junction of the orbital septum and the levator aponeurosis in Orientals

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1 British Journal of Plastic Surgery (1998), 51, The British Association of Plastic Surgeons I BRITISH JOURNAL OF PLASTIC SURGERY An anatomical study of the junction of the orbital septum and the levator aponeurosis in Orientals K. Hwang, D. J. Kim*, R. S. Chungt, S. I. Lee and Y. Hiraga:~ Departments of Plastic Surgery and *Anatomy, College of Medicine, Inha University, Inchon, Korea; l" Chung's Institute of Plastic Surgery, Seoul, Korea; and r Hiraga Plastic Surgery Clinic, Tokyo, Japan SUMMARY. The anatomical relationships of the orbital septum and levator aponeurosis has been studied in 40 eyelids subjected to blepharoplasty and corrective ptosis surgery by dissection in 10 cadavers and in histological sections. The orbital septum originates from the arcus marginalis of the frontal bone and consists of two layers. The whitish outer (superficial) layer, containing vertically running vessels, descends just inside the orbicularis oculi muscle to interdigitate with the levator aponeurosis with loose connective tissue, then disperses inferiorly. The inner (deep) layer follows the superficial one initially, then reflects at the levator aponeurosis and continues posteriorly with the levator sheath. We reconfirmed Whitnall's original description that the levator sheath thickens to form the superior transverse ligament runs continuously inferiorly anterior to the levator aponeurosis and forms the inner layer of the orbital septum. This detailed anatomical analysis should assist in performing upper eyelid surgery such as the Oriental double fold operation or levator resection. The palpebral creases in the Oriental eyelid are not as distinctive as those in occidental races. A detailed knowledge of the lids is essential in performing Oriental double fold surgery. The origin and course of the levator palpebrae muscle is well defined, but not the relationship between the levator aponeurosis and orbital septum. 1 ~3 The purpose of this study is to clarify the fusing of the levator aponeurosis and orbital septum on the limited midaxial plane. Materials and methods Cadaver study Ten postmortem orbits with the eyelids were studied (5 cadavers), one half for gross dissection and the other for histological sections. Transverse incisions were made on the eyelid skin at 7 mm above the ciliary margin and a strip of orbicularis oculi muscle was removed. After the junction of the orbital septum and levator aponeurosis was observed, blunt dissection was carried out through the outer layer of orbital septum and continued between levator aponeurosis and the membrane (inner layer of orbital septum) which covers the posterior surface of orbital fat. The blunt dissection was continued to the superior transverse ligament of Whitnall. Anteriorly the floor of the pre-aponeurotic space was observed on the mid-sagittal plane. For histology the specimens of the orbit and eyelid were fixed in 10% buffered formalin (ph 7.4) for 3 days, and then embedded in paraffin. The specimens were cut in 8 gm sections mounted on glass slides and left overnight at 60~ After deparaffinisation with xylene the sections were rinsed with distilled water and stained by Mallory's method. TM 594 Intra-operative observation Forty eyelids were studied during double fold blepharoplasty and external correction of ptosis (15 cases). After usual skin preparation and local anaesthesia with 1% Xylocaine containing Epinephrine (1:100000) an upper palpebral crease incision was made at 6 mm above the ciliary margin. A strip of orbicularis oculi muscle was removed and the junction between the orbital septum and levator aponeurosis was observed. Blunt dissection was carried out through the outer layer of the orbital septum and continued between the levator aponeurosis and the inner layer of the orbital septum which covers the posterior surface of the orbital fat. The orbital fat covered with the layer of orbital septum was reflected upward, and the superior transverse ligament of Whitnall which was continuous to the inner layer of orbital septum was examined. Results Dissection The orbital septum originates from the arcus marginalis of the frontal bone and consists of two layers. The outer (superficial) whitish layer, containing vertically running vessels, descends just posteriorly to the orbicularis oculi muscle and reaches the levator aponeurosis with a loose attachment of connective tissue, before it disperses inferiorly. The inner (deep) layer runs closely abreast, reflects at the levator aponeurosis and continues superiorly and posteriorly to levator sheath. Tracing the deep layer leads to the superior transverse ligament of Whitnall above the levator aponeurosis. The levator muscle sheath is thickened and forms Whitnall's ligament with a contribution from posteriorly coursing fibres from the inner layer of the orbital septum (Fig. 1).

2 Oriental upper eyelid anatomy 595 A LM B Figure 1--(A) Photograph of a sagittally dissected upper eyelid. The orbital septum (S), which starts at the arcus marginalis of the frontal bone, has two layers. The outer (superficial) layer (OS), which is whitish and contains vertically running vessels, descends just behind the orbicularis oculi muscle until it reaches the aponeurosis of the levator palpebrae superioris muscle (LM). The inner (deep) layer (IS) is continued to the levator sheath, which is thickened to form a transverse ligament (W). (B) Schema of Figure 1A. IS, inner (deep) layer of orbital septum; LM, levator palpebrae superioris muscle; OS, outer (superficial) layer of orbital septum; S, orbital septum; W, Whitnall's superior transverse ligament. Microscopic study A midsagittal section of the orbit includes the levator palpebrae muscle, orbital septum, sheath of levator muscle and Whitnall's ligament. Thick collagen fibres of the orbital septum wall off the pre-aponeurotic fat. The deep collagen fibres (inner layer of orbital septum) continued to Whitnall's ligament and to the levator sheath (Fig. 2). Intra-operative observations The orbital septum entered and its deep layer reflects at the aponeurosis and reaches Whitnall's ligament with aponeurosis (Figs 3 & 4). Figure 2--(A) Micrograph of a human upper eyelid in sagittal section. The outer (superficial) layer (OS) is fused with the inner (deep) layer (IS) to form the orbital septum (S) at the inferior margin of the orbital fat. Haematoxylin and eosin stain, x 20. (B) Schema of Figure 2A. The sheath of the levator (LS) is thickened to form the transverse ligament of Whitnall (W) just before the levator muscular portion (LM) becomes the aponeurosis (LA). The thin forward continuation of the sheath of the levator muscle (LS) can be traced to the inner layer of the orbital septum (IS) as a delicate layer. (C) Higher magnification of the boxed area of Figure 2A. The inner layer of the orbital septum (IS), which lies in front of the orbital fat (F), is continuous with the levator sheath (LS), which covers the levator aponeurosis (LA). IS, inner layer of orbital septum; LA, levator aponeurosis; LS, Ievator sheath; M, Muller's muscle; OS, outer layer of orbital septum; S, orbital septum; W, Whitnall's superior transverse ligament. Discussion tn Gray's Anatomy '5 the elevation of the upper eyelid is considered to be checked by the orbital septum. There is considerable confusion regarding the relationship of the levator aponeurosis to the orbital septum. The current predominant view is that the orbital septum attaches to the levator aponeurosis, orbital fat lies posterior to the septum and anterior to the aponeurosis, and no distinct layer exists between the aponeurosis and fat pad. ~ 13

3 596 British Journal of Plastic Surgery 13 Figure 3--(A) After incising through the orbital septum, the levator sheath (arrow) is seen just in front of the levator aponeurosis. (B) Key to Figure 3A. F, orbital fat; LS, levator sheath. B Figure 4~(A) Upon blunt dissection, the sheath of levator is traced to Whitnall's ligament which is about 16 mm from the lid margin. (B) Key to Figure 4A. F, orbital fat; LS, levator sheath. In 1910 Whitnall '6a7 described how, in a vertical section through the orbit, the superficial part of the levator sheath forms a conspicious band above the levator palpebrae muscle just behind the aponeurosis. The levator sheath is traced anteriorly as a delicate layer of connective tissue running over the aponeurosis and posterior to the orbital septum, ending at the periosteum of the supraorbital bony rim just posterior to the origin of the orbital septum (Fig. 5). It is well known that Whitnall's ligament is a thickened portion of the levator sheath, but continuation of the sheath anteriorly to the course of the orbital septurn has not been described. We refer to it as the inner (deep) layer of the orbital septum. Sappey, TM in 1867, observed that a fibrous arch transversely covers the levator muscle, adheres to it and forms part of the orbital septum. Testuf 9 described how the sheath of the levator forms the orbital septum. These descriptions are supported by our study which shows an inner layer of orbital septurn corresponding to the continuing levator sheath. Fink 2~ reported that the fascial sheath of the levator palpebrae muscle continues anteriorly from Whitnall's ligament as a continuous membrane which can be traced up to the supraorbital rim where it blends with the orbital septum. Our study shows that the inner layer of the orbital septum (Fink's membrane) inserts to the periorbital periosteum posterior to the orbital septum instead of blending with it. Hitasomi 21 indicated that the levator aponeurosis goes inferiorly posterior to the orbital fat. Between the levator aponeurosis and the orbital fat there exists a single one-layered translucent membrane. He suggested that after removal of pre-aponeurotic fat in double fold surgery the orbital septum is sutured to the membrane in front of the aponeurosis. Hitasomi's 'one-layered translucent membrane-like structure' corresponds to the inner layer of the orbital septum. Hiraga 2~ noted five layers: the first layer is skin, the second orbicularis oculi muscle, the third the whitish orbital septum with vertically running blood vessels, the fourth the outer capsule of orbital fat with horizontally running capillaries and the fifth layer a translucent inner layer through which bright yellow orbital fat is seen. The fourth layer corresponds to the inner layer of the orbital septum. In Oriental double fold operations, one of the most commonly used methods is to suture the dermis of the lower flap to the levator aponeurosis. Sometimes, however, the double fold disappears several months after surgery. The reason for this failure, we think, is that the suture is fixed only to the inner layer of the orbital septum instead of being tightly secured to the levator aponeurosis. There is some loose connective tissue between the inner layer of the orbital septum and the levator aponeurosis; therefore, when the surgeon holds the inner layer of the orbital septum and the levator aponeurosis together after opening the anterior portion of the orbital septum, the underlying levator cannot easily be grasped. Flowers 23 described

4 Oriental upper eyelid anatomy 597 Sept. orb.-n~ Roll of fat -.-.'~ Palp. apron.---- Sheath of Levator palpebrae superioris / Figure ~-Vertical section through the orbit. The superficial layer of the sheath of the levator palpebrae superioris alone is shown. The ligament formed by the thickening of this sheath above the anterior part of the muscle is seen cut in section, and the thin forward continuation of the sheath can be traced above the aponeurosis (palp. apon.) to be attached to the supra-orbital margin behind the septum orbitale (sept. orb). The reflection of the latter on to the aponeurosis is seen. Muller's muscle is shown lying beneath the aponeurosis, connecting the levator with the superior margin of the tarsal plate. Reproduced with kind permission from Whitnall SE, J Anat Physiol 1910; XIV: 131. this relationship between the orbital septum and the levator aponeurosis as 'uncertain integrity of the connection between septum and aponeurosis', which occasionally leads to fold diminution. We recommend blunt dissection between the inner layer of the orbital septum and the levator aponeurosis, reflecting the orbital fat which is covered by the inner layer of the orbital septum, then carrying out the levator~lermal fixation in making the double fold. In levator resection for treatment of blepharoptosis, some surgeons lift up the levator aponeurosis from the underlying Muller's muscle without cutting the conjunctiva. 24,25 It is important, especially in secondary surgery, not to confuse the inner layer of the orbital septum with the underlying levator aponeurosis. In summary, we reconfirmed Whitnall's original description that the levator sheath thickens to form the superior transverse ligament of Whitnall, runs continuously inferiorly anterior to the levator aponeurosis and forms the deep layer of the orbital septum. Acknowledgements We would like to express our thanks to Albert Hornblass, MD, FACS, Director, Oculoplastic Surgery, Manhattan EENT Hospital, NY, USA for reviewing this article. This study was supported by a grant from Inha University. References 1. Doxanas MT, Anderson RL. Oriental eyelids: an anatomic study. Arch Ophthalmol 1984; 102: Anderson RL, Beard C. The levator aponeurosis: attachments and their clinical significance. Arch Ophthalmol 1977; 95: 1437~tl. 3. Anderson RL, Dixon RS. The role of Whitnall's ligament in ptosis surgery. Arch Ophthalmol 1979; 97: Zide BM. Anatomy of the eyelids. Clin Plast Surg 1981; 8: Siegel R. Surgical anatomy of the upper eyelid fascia. Ann Plastic Surg 1984; 13: Meyer DR, Linberg JV, Wobig JL, McCormick SA. Anatomy of the orbital septum and associated eyelid connective tissues. Implications for ptosis surgery. Ophthalmic Plast Reconstr Surg 1991; 7: Lemke BN, Stasior OG, Rosenberg PN. The surgical relations of the levator palpebrae superioris muscle. Ophthalmic Plast Reconstr Surg 1988; 4: Stasior GO, Lemke BN, Wallow IH, Dortzbach RK. Levator aponeurosis elastic fiber network. Opthalmic Plast Reconstr Surg 1993; 9: Ettl A, Priglinger S, Kramer J, et al. Functional anatomy of the levator palpebrae superioris muscle and its connective system. Br J Ophthalmol 1996; 80: Codere F, Tucker NA, Renaldi B. The anatomy of Whitnall ligament. Ophthalmol 1995; 102: Liu D, Hsu WM. Oriental eyelids: anatomic difference and surgical consideration. Opthalmic Plast Reconstr Surg 1986; 2: Kim MK, Rathbun JE, Aguilar GL, Seiff SR. Ptosis surgery in the Asian eyelid. Opthalmic Plast Reconstr Surg 1989; 5:

5 598 British Journal of Plastic Surgery 13. Chen WED. Concept of triangular, trapezoidal, and rectangular debulking of eyelid tissues: application in Asian blepharoplasty. Plast Reconstr Surg 1989; 85: Luna LG. Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology, 3rd Edn. New York: McGraw-Hill, 1960; Williams PL, Warwick R. Gray's Anatomy, 36th Edn. Edinburgh: Churchill Livingstone, 1980; Whitnall SE. On a ligament acting as a check to the action of the levator palpebrae superior muscle. J Anat Physiol 1910; XIV: 131M Whitnall SE. The Anatomy of Human Orbit and Accessory Organs of Vision. London: Humphrey Milford Oxford University Press, 1932; 135M Sappey. Traite d'anatomie Descriptive, 4th Edn. Paris, 1867; Testut L. Traite d'anatomie humanie, 5th Edn. Paris, Fink WH. An anatomic study of the check mechanism of the vertical muscles of the eyes. Am J Ophthalmol 1957; 44: Hitasomi C. Palpebra, Anatomy and consideration towards plastic operation. Clin Ophthalmol 1976; 30: Hiraga Y. The double eyelid operation and augmentation rhinoplasty in the Oriental patient. Clin Plast Surg 1980; 7: Flowers RS. Discussion: Simplified anatomic method of double-eyelid operation: septodermal fixation technique by Lee JS, Park W J, Shin MS and Song IC. Plast Reconstr Surg 1997; 100: Dortzbach RK, Gausas RA, Sherman DD. Blepharoptosis. In: Dortzbach RK (ed). Opthalmic Plastic Surgery. New York: Raven, Putnam JR, Nunery WR, Tanenbaum M, McCord CD Jr. Blepharoptosis. In McCord CD (Ed). Oculoplastic Surgery. New York: Raven, The Authors Kun Hwang MD, PhD, Associate Professor, Se II Lee MD, DMSe, Professor and Chief, Department of Plastic Surgery, Inha University Hospital, Sinheung-dong, Chung-gu, Inchon , Korea. Dae Joong Kim PhD, Associate Professor, Department of Anatomy, College of Medicine, Inha University, 253, Yonghyundong, Nam-gu, Inchon , Korea. Robert S. Chung MD, FACS, Chung's Institute of Plastic Surgery, 815-4, Yeoksam-dong, Kangnam-gu, Seoul, Korea. Yoshio Hiraga MD, Director, Hiraga Plastic Surgery Clinic, Asagaya-Kita Duginami-Ku, Tokyo 166, Japan. Correspondence to Dae Joong Kim. Paper received 10 December Accepted 22 July 1998, after revision.