한국인 눈둘레근의 국소해부학적 연구

Abstract

The aim of this study was to examine in detail the anatomical variations in the orbicularis oculi muscle (OOc) and relationship of the zygomaticus minor muscle (ZMi) with the OOc, thereby providing an anatomic basis for explaining facial animation, dimple formation, and attachment to the periorbital muscle. Sixty-one hemifaces from embalmed Korean adult cadavers (34 males, 27 females; age range, 45～85 years; mean age, 62.6 years; 28 bilateral and 5 unilateral) were used in this study. After careful removal of the skin and subcutaneous tissues, the region around the OOc was dissected and observed in detail. From the dissected specimens, the morphology and variations of the musculature around the OOc were observed. The OOc was studied as three parts such as lateral, medial, and inferior region. In addition, H-E stain for observing the muscle fiber mixed with zygomaticus minor was performed with only one side. Four Types of lateral muscular band were observed lateral to the OOc. Type A, in which the lateral muscular band terminates at the zygomatic arch, was observed in 27.9% of cases. Type B, in which the lateral muscular band terminates at the cheek, occurred in 18.0% of cases; the muscle fibers from the muscular band were inserted into the dermis of the cheek. Type C, in which the lateral muscular band ends at the angle of mouth was found in 8.2% of cases, and there was no lateral muscular band from the OOc (Type D) in 45.9% of cases. The four Types of muscular band observed medial to the OOc were shown in this study. As a circular muscle unit along with the lateral, inferior, and medial edges of the OOc, in Type I (23.0%) it attached to the frontal belly without being attached to the medial canthal tendon. In Type II (23.0%) it originated from the medial canthal tendon at the lower portion of the OOc and inserted into the cheek skin. In Type III (19.6%) it inserted into the cheek skin and attached to the frontal belly without being attached to the medial canthal tendon. There was no medial muscular band of the OOc in Type IV (34.4%). The anatomical patterns of Types II and III were further classified into two subtypes (a and b), depending on the location of the muscle insertion. In Type a (23.0%) it originated from the medial canthal tendon and extended obliquely downwards; it did not pass the inferior edge of the OOc. In Type b (19.6%) it passed the inferior edge of the OOc. The prevalence of mixing of the belly of the orbital part of the outer edge of the OOc with the ZMi was 88.5%, and that of blending of the ZMi muscular band into the lower inner corner of the OOc was 55.7%. As a result of the studies, we concluded that the OOc is closely related to the midface, upper lip, and also the cheek. This result will be given as basic data for understanding facial expressions and for performing composite rhytidectomy.