Positional relationships of the origin and course of zygomaticus major with the nasal ala, tragus, philtrum, and lateral canthus for aesthetic treatments and surgeries.

Abstract

The aim of this study was to characterize the origin and course of the zygomaticus major muscle (Zmj) with its topographic relationships with the nasal ala, tragus, philtrum, and lateral canthus. The Zmj was examined in 50 specimens of 25 embalmed adult Korean cadavers. Facial muscles were dissected to expose the origin and course of the Zmj in 48 specimens of 24 cadavers. The 25th cadaver was sectioned to obtain images of the Zmj. The positional relationships of the Zmj origin with the nasal ala and the tragus were classified into three categories. A horizontal line through the center of the Zmj origin and the nasal ala passed through the tragus in 20 of 48 specimens (41.7%), the intertragic notch in 18 specimens (37.5%), and above the tragus in 10 specimens (20.8%).In a horizontal section of the head, the Zmj origin was located near the level of the nasal ala and tragus. In a coronal section of the head, the fibers of the Zmj arising at its origin were located close to the zygomatic bone, lateral to the zygomaticus minor muscle. By combining dissection with the analysis of sectioned images and ultrasound images of the Zmj, this study has yielded positional information for easily predicting the location of the origin and the course of the Zmj and its related structures underlying the skin.