Developed Lower-Positioned Transverse Ligament Restricts Eyelid Opening and Folding and Determines Japanese as Being With or Without Visible Superior Palpebral Crease

Midori Ban, MD; Kiyoshi Matsuo, MD, PhD; Ryokuya Ban, MD, PhD; Shunsuke Yuzuriha, MD, PhD; and Ai Kaneko, MD

Disclosures

ePlasty. 2013;13 

In This Article

Abstract and Introduction

Abstract

Introduction: We have reported that a developed lower-positioned transverse ligament between the superior-medial orbital rim and the lateral orbital rim on the lateral horn in the lower orbital fat space antagonizes eyelid opening and folding in certain Japanese to produce narrow eye, no visible superior palpebral crease, and full eyelid. In this study, we confirmed relationship between development of the lower-positioned transverse ligament and presence of the superior palpebral crease.

Methods: We evaluated whether (1) digital immobilization of eyebrow movement during eyelid opening and (2) a developed lower-positioned transverse ligament could classify Japanese subjects as being with or without visible superior palpebral crease.

Results: Digital immobilization of eyebrow movement restricted eyelid opening in all subjects without visible superior palpebral crease but did not restrict in any subject with visible superior palpebral crease. Macroscopic and microscopic evidence revealed that the lower-positioned transverse ligament behind the lower orbital septum in subjects without visible superior palpebral crease was significantly more developed than that in subjects with visible superior palpebral crease.

Conclusions: Since a developed lower-positioned transverse ligament antagonizes opening and folding of the anterior lamella of the upper eyelid in subjects without visible superior palpebral crease, these individuals open their eyelids by lifting the eyebrow with the anterior lamella and the lower-positioned transverse ligament owing to increased tonic contraction of the frontalis muscle, in addition to the retractile force of the levator aponeurotic expansions. In subjects with visible superior palpebral crease, the undeveloped lower-positioned transverse ligament does not antagonize opening and folding of the anterior lamella, and so they open their eyelids by folding the anterior lamella on the superior palpebral crease via the retractile force of the levator aponeurotic expansions.

Introduction

According to anthropological studies, the Japanese are genetically divided into the Neolithic Jomon natives and the Bronze Yayoi migrants from the cold Asian continent.[1–6] The Yayoi migrants were reported to possess eyelid structures for cold tolerance, such as narrow eye, no visible superior palpebral crease (SPC), full eyelid, and high-positioned round supraorbital margin (Fig 1a), whereas the Jomon natives were reported to have features of wide eye, visible SPC, and low-positioned straight supraorbital margin (Fig 1b).

Figure 1.

Anatomy and neurophysiology related to eyelid opening. (a) Subjects without visible SPC or Jomon natives. (b) Subjects with visible SPC or Yayoi migrants. ? indicates unknown nucleus; FAST, fast-twitch muscle fibers; FEF, frontal eye field; III CCN, central caudal nucleus of the oculomotor nuclear complex; LTL, lower-positioned transverse ligament; mesV, mesencephalic trigeminal nucleus; PHASIC, phasic contraction; PMN, premotor neurons in the rostral interstitial nucleus of the medial longitudinal fasciculus; REF, reflex contraction; SLOW, slow-twitch muscle fibers; SPC, superior palpebral crease; TONIC, tonic contraction; VII FM, frontalis motor neurons; VOL, voluntary contraction; W, Whitnall's ligament.

We have demonstrated that the presence of a developed lower-positioned transverse ligament (LTL) between the superior-medial orbital rim and the lateral orbital rim on the lateral horn in the lower orbital fat space, around which the superficial levator aponeurosis turns upwards to become the orbital septum, produces distinct features that include narrow eye, no visible SPC, and full eyelid, all of which correspond to features of the Yayoi migrants (Fig 1a).[7,8] We hypothesized that a developed LTL in the lower fat pad space antagonizes opening of the eyelid, which leads to narrow eye, as well as folding of the anterior lamella of the upper eyelid owing to retraction of the levator aponeurosis expansions, which results in no visible SPC, and keeps the orbital fat in the lower position, which results in full eyelid (Fig 1a).[7,8] To maintain an adequate visual field in primary gaze under these circumstances, increased contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to enhance the levator skeletal slow-twitch muscle fibers and induce not only phasic, but also tonic, reflex contraction of the frontalis skeletal slow-twitch muscle fibers (Fig 1a).[8–24] The tonic reflex contraction of the frontalis muscle persistently lifts the eyebrow,[23] which carries both the anterior lamella of the upper eyelid and the LTL, even in primary gaze, and functions as another eyelid-opening mechanism (Fig 1a).

On the contrary, the absence of a developed LTL in the lower orbital fat space appears to produce certain features that include wide eye, visible SPC, and no full eyelid, all of which correspond to features of the Jomon natives (Fig 1b).[7,8] We also hypothesized that an undeveloped LTL does not antagonize either opening of the eyelid, thus producing wide eye, or folding of the anterior lamella via retraction of the levator aponeurosis expansions, thereby resulting in visible SPC, and that movement of the orbital fat in the lower position precludes full eyelid (Fig 1b).[7,8] To maintain an adequate visual field, Jomon natives need not persistently lift the eyebrow with the anterior lamella and weak LTL in primary gaze (Fig 1b).

Modern Japanese people continue to exhibit features of the Jomon natives or Yayoi migrants. Since the absence of visible SPC indicates the anterior lamella of the upper eyelid to be unfoldable and require lifting of the eyebrow for maintenance of an adequate visual field, we considered this to be the key distinguishing trait of descendants of the Yayoi migrants in this study. In contrast, we presumed the presence of visible natural SPC to specifically indicate the anterior lamella of the upper eyelid as being foldable on the SPC without lifting the eyebrow for maintenance of an adequate visual field in Japanese stemming from Jomon native ancestry.

Digital immobilization of eyebrow movement during eyelid opening from closed eyelid to primary gaze counteracts the contraction of the frontalis muscle to lift the eyebrow with the anterior lamella of the upper eyelid and is commonly used to exclude involvement of eyebrow lifting when impaired levator function is evaluated in congenital blepharoptosis (Fig 2c). This technique was also used to observe how the LTL antagonizes eyelid opening in our cohort.

Figure 2.

A 23-year-old man without visible SPC suffering from right congenital blepharoptosis. (a, b) Primary and upward gaze. (c) Digital immobilization of eyebrow movement restricts opening of not only the congenitally ptotic right eyelid but also the normal left eyelid. (d) Arrow indicates the lowest LTL between the superior-medial orbital rim and the lateral orbital rim on the lateral horn in the lower orbital fat space. (e) Arrows indicate 3 LTLs. Abbreviations are explained in the caption of Figure 1.

To verify our hypotheses, we evaluated whether (1) digital immobilization of eyebrow movement during eyelid opening and (2) a developed LTL that restricts eyelid opening and folding could classify Japanese subjects as being with or without visible SPC.

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