title: Quantitative anatomical analysis of facial expression using a 3D motion capture system: Application to cosmetic surgery and facial recognition technology.
abstract: The topography of the facial muscles differs between males and females and among individuals of the same gender. To explain the unique expressions that people can make, it is important to define the shapes of the muscle, their associations with the skin, and their relative functions. Three-dimensional (3D) motion-capture analysis, often used to study facial expression, was used in this study to identify characteristic skin movements in males and females when they made six representative basic expressions. The movements of 44 reflective markers (RMs) positioned on anatomical landmarks were measured. Their mean displacement was large in males [ranging from 14.31 mm (fear) to 41.15 mm (anger)], and 3.35-4.76 mm smaller in females [ranging from 9.55 mm (fear) to 37.80 mm (anger)]. The percentages of RMs involved in the ten highest mean maximum displacement values in making at least one expression were 47.6% in males and 61.9% in females. The movements of the RMs were larger in males than females but were more limited. Expanding our understanding of facial expression requires morphological studies of facial muscles and studies of related complex functionality. Conducting these together with quantitative analyses, as in the present study, will yield data valuable for medicine, dentistry, and engineering, for example, for surgical operations on facial regions, software for predicting changes in facial features and expressions after corrective surgery, and the development of face-mimicking robots.
authors: Department of Dental Hygiene, School of Health and Medicine, Namseoul University, Cheonan, South Korea.
authors: Jae-Gi
authors: JG
authors: Lee
authors: Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, Yonsei University College of Dentistry, Seoul, South Korea.
authors: Su-Jin
authors: SJ
authors: Jung
authors: Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, Yonsei University College of Dentistry, Seoul, South Korea.
authors: Hyung-Jin
authors: HJ
authors: Lee
authors: Department of Advanced General Dentistry, Yonsei University College of Dentistry, Seoul, South Korea.
authors: Jung-Hyuk
authors: JH
authors: Seo
authors: Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, Yonsei University College of Dentistry, Seoul, South Korea.
authors: You-Jin
authors: YJ
authors: Choi
authors: Department of Dental Hygiene, School of Health and Medicine, Namseoul University, Cheonan, South Korea.
authors: Hyun-Sook
authors: HS
authors: Bae
authors: Department of Oral Anatomy, Dankook University College of Dentistry, Cheonan, South Korea.
authors: Jong-Tae
authors: JT
authors: Park
authors: Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, Yonsei University College of Dentistry, Seoul, South Korea.
authors: Hee-Jin
authors: HJ
authors: Kim
mesh_terms: D000328:Adult; D004867:Equipment Design; D005149:Facial Expression; D005152:Facial Muscles / Q000033:anatomy & histology*; D000066499:Facial Recognition; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008297:Male; D015361:Rhytidoplasty; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013518:Surgery, Plastic / Q000379:methods*
keywords: 3D motion capture; facial expression; facial movement; quantitative analysis;  anatomical landmarks