NEW INSIGHTS OF THE ZYGOMATICUS MINOR MUSCLE CONNECTING THE ORBITAL AND MOUTH REGIONS: ITS ARRANGEMENT AND ATTACHMENTS

Abstract

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Aim. The present study aimed to investigate the arrangement and terminal attachments of the zygomaticus minor muscle (Zmi) fibers connecting the orbital and mouth regions. Material and Methods. The Zmi was examined in 32 specimens of embalmed Korean adult cadavers. The Zmi fibers were traced to observe their arrangement and attachments. Results and Discussion. The Zmi was formed by the muscle fibers that arose from the zygomatic bone and the muscle fibers that extended from the orbicularis oculi muscle (OOc) in 96.9%. When the Zmi inserted into the upper lip, ithad more muscle fibers from the OOc than the zygomatic bone in 31.3%, and from the zygomatic bone than the OOc in 50.0%. Amounts of the Zmi fibers from the zygomatic bone and the OOc were similar in 15.6%. In 93.8%, the muscle fibers that extended from the OOc constituted the lateral margin of the Zmi, usually descending to the level between the nasal ala and the vermilion border of the upper lip and inserting into the upper lip. Some of the Zmi fibers that arose from the zygomatic bone blended with the inferior fibers of the OOc in 40.6%, and they constituted the inferior and medial margins of the OOc. Conclusions. The data regarding the arrangement and attachments of the Zmi fibers connecting the orbital and mouth regions will be useful for electro myographic analyses, botulium toxin type A therapies, and various facial surgeries.