An anatomical study of the insertion of the zygomaticus major muscle in humans focused on the muscle arrangement at the corner of the mouth.
BACKGROUND
The aim of this study was to clarify the arrangement of the zygomaticus major muscle by means of topographic examination, and to evaluate the anatomical variations in the insertion of the zygomaticus major at the perioral region.


METHODS
After a detailed dissection in the modiolar region, the insertion area of the zygomaticus major was observed in 70 embalmed cadavers.


RESULTS
At the perioral region of the dissected specimens, the anatomical aspects of the muscular arrangement and attachment of the zygomaticus major muscle were classified into four categories. In type I, the superficial muscle band of the zygomaticus major is blended and interlaced with the levator anguli oris, whereas the fibers of the deep muscle band blend into the buccinator, passing deeper to the levator anguli oris; this was the situation most commonly encountered (54.3 percent). It was found that the insertion of the zygomaticus major was divided into superficial and deep bands (types I and IV) [42 cases (60 percent)] and into three layers of superficial, middle, and deep fibers (type II) [17 cases (24.3 percent)]. The others were cases where the zygomaticus major was inserted deep into the levator anguli oris as a single muscle band (type III) [11 cases (15.7 percent)].


CONCLUSIONS
The arrangement and insertion patterns of the zygomaticus major in this study are expected to provide critical information for surgical planning for the procedure of facial reanimation surgery.
Shim
Kyoung-Sub
KS
Seoul and Chungju, Korea; and Lille, France From the Division of Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, Brain Korea 21 Project, College of Dentistry, Human Identification Research Center, Yonsei University; Department of Anatomy, College of Medicine, Konkuk University; and Laboratoire d'Anatomie, Faculté de Medécine, Henri Warembourg.
Hu
Kyung-Seok
KS
Kwak
Hyun-Ho
HH
Youn
Kwan-Hyun
KH
Koh
Ki-S
KS
Fontaine
Christian
C
Kim
Hee-Jin
HJ
D000368:Aged; D002102:Cadaver; D005152:Facial Muscles / Q000033:anatomy & histology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D009055:Mouth / Q000033:anatomy & histology*; D019651:Plastic Surgery Procedures / Q000379:methods; D012060:Rejuvenation